2021-11-25  6bb9d9283adf481936875eacc408fae7 99+   1 小时   12.5 k0次访问

关于 Kubernetes中Pod的一些笔记

钱比你想象的重要得多，超过20岁了就别整天活在梦里了，对于平凡的你来讲，钱就是你的尊严。

写在前面

  • 学习K8s，刚把Pod学完，整理笔记记忆
  • 笔记主要是Pod的一些基本操作,偏实战,没有理论：
  • 笔记内容包括:
    • 创建Pod的两种方式，相关镜像下载，重启机制
    • Pod的详细信息，日志、命令运行等、生命周期等
    • 初始化Pod和静态Pod
    • Pod的调度(选择器、指定节点、主机亲和性)
    • 节点的coedon与drain
    • 节点的taint(污点)及容忍污点(tolerations)
    • 部分地方使用了ansible，但是不影响阅读

Pod 学习环境测试

ansible ping测试

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┌──[root@vms81.liruilongs.github.io]-[~]
└─$cd ansible/
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible node -m ping
192.168.26.82 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "ping": "pong"
}
192.168.26.83 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "ping": "pong"
}

docker环境测试

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.83 -m shell -a "systemctl enable docker --now"
192.168.26.83 | CHANGED | rc=0 >>
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl get nodes
NAME                         STATUS   ROLES                  AGE     VERSION
vms81.liruilongs.github.io   Ready    control-plane,master   7d23h   v1.21.1
vms82.liruilongs.github.io   Ready    <none>                 7d23h   v1.21.1
vms83.liruilongs.github.io   Ready    <none>                 7d23h   v1.21.1
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

一、帮助文档的使用

kubectl explain --help

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl explain --help

查看pod的语法结构

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl explain pods
KIND:     Pod
VERSION:  v1
DESCRIPTION:
     Pod is a collection of containers that can run on a host. This resource is
     created by clients and scheduled onto hosts.
FIELDS:
   apiVersion   <string>
  ....
   kind <string>
  .....
   metadata     <Object>
  .....
   spec <Object>
  .....
   status       <Object>
  ....
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl explain pods.metadata
KIND:     Pod
VERSION:  v1

二、创建Pod的方式

这里因为是学习，所以我们新建一个命名空间用于学习

新建命名空间:

kubectl config set-context context1 --namespace=liruilong-pod-create

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$mkdir k8s-pod-create
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cd k8s-pod-create/
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl create ns liruilong-pod-create
namespace/liruilong-pod-create created

查看当前集群信息

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl config view
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: DATA+OMITTED
    server: https://192.168.26.81:6443
  name: cluster1
contexts:
- context:
    cluster: cluster1
    namespace: kube-system
    user: kubernetes-admin1
  name: context1
current-context: context1
kind: Config
preferences: {}
users:
- name: kubernetes-admin1
  user:
    client-certificate-data: REDACTED
    client-key-data: REDACTED

查看命名空间

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get  ns
NAME                   STATUS   AGE
default                Active   8d
kube-node-lease        Active   8d
kube-public            Active   8d
kube-system            Active   8d
liruilong              Active   7d10h
liruilong-pod-create   Active   4m18s

设置刚才新建的命名空间为当前命名空间

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl config set-context context1 --namespace=liruilong-pod-create
Context "context1" modified.
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$docker pull nginx
Using default tag: latest
latest: Pulling from library/nginx
b380bbd43752: Pull complete
fca7e12d1754: Pull complete
745ab57616cb: Pull complete
a4723e260b6f: Pull complete
1c84ebdff681: Pull complete
858292fd2e56: Pull complete
Digest: sha256:644a70516a26004c97d0d85c7fe1d0c3a67ea8ab7ddf4aff193d9f301670cf36
Status: Downloaded newer image for nginx:latest
docker.io/library/nginx:latest

命令行的方式创建pod

kubectl run podcommon --image=nginx --image-pull-policy=IfNotPresent --labels="name=liruilong" --env="name=liruilong"

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl run podcommon --image=nginx --image-pull-policy=IfNotPresent --labels="name=liruilong" --env="name=liruilong"
pod/podcommon created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods
NAME        READY   STATUS              RESTARTS   AGE
podcommon   0/1     ContainerCreating   0          12s

查看pod调度到了那个节点

kubectl get pods -o wide 

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl run pod-demo --image=nginx  --labels=name=nginx --env="user=liruilong" --port=8888  --image-pull-policy=IfNotPresent
pod/pod-demo created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl  get pods -o wide
NAME          READY   STATUS    RESTARTS   AGE     IP               NODE                         NOMINATED NODE   READINESS GATES
pod-demo      1/1     Running   0          94s     10.244.171.149   vms82.liruilongs.github.io   <none>           <none>
poddemo       1/1     Running   0          8m22s   10.244.70.41     vms83.liruilongs.github.io   <none>           <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

删除pod

kubectl delete pod pod-demo --force 

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl delete pod pod-demo --force
warning: Immediate deletion does not wait for confirmation that the running resource has been terminated. The resource may continue to run on the cluster indefinitely.
pod "pod-demo" force deleted
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods | grep pod-
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

每个Pod都有一个pause镜像

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.83 -m shell -a "docker ps | grep podcomm"
192.168.26.83 | CHANGED | rc=0 >>
c04e155aa25d   nginx                                                 "/docker-entrypoint.…"   21 minutes ago   Up 21 minutes             k8s_podcommon_podcommon_liruilong-pod-create_dbfc4fcd-d62b-4339-9f15-0a48802f60ad_0
309925812d42   registry.aliyuncs.com/google_containers/pause:3.4.1   "/pause"                 21 minutes ago   Up 21 minutes             k8s_POD_podcommon_liruilong-pod-create_dbfc4fcd-d62b-4339-9f15-0a48802f60ad_0

生成yaml文件的方式创建pod：-o yaml

kubectl run pod-demo --image=nginx --image-pull-policy=IfNotPresent --dry-run=client -o yaml >pod-demo.yaml

yaml文件的获取方法:-o yaml

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]  # yaml文件的获取方法:
└─$kubectl run pod-demo --image=nginx --image-pull-policy=IfNotPresent --dry-run=client -o yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod-demo
  name: pod-demo
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: pod-demo
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

yaml文件创建pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl run pod-demo --image=nginx --image-pull-policy=IfNotPresent --dry-run=client -o yaml >pod-demo.yaml

pod-demo.yaml

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod-demo
  name: pod-demo
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: pod-demo
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

yaml文件创建pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply -f pod-demo.yaml
pod/pod-demo created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide
NAME        READY   STATUS    RESTARTS   AGE   IP            NODE                         NOMINATED NODE   READINESS GATES
pod-demo    1/1     Running   0          27s   10.244.70.4   vms83.liruilongs.github.io   <none>           <none>
podcommon   1/1     Running   0          13m   10.244.70.3   vms83.liruilongs.github.io   <none>           <none>

删除pod：delete pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl delete pod pod-demo
pod "pod-demo" deleted
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide
NAME        READY   STATUS    RESTARTS   AGE   IP            NODE                         NOMINATED NODE   READINESS GATES
podcommon   1/1     Running   0          14m   10.244.70.3   vms83.liruilongs.github.io   <none>           <none>

Pod指定命令/删除pod/批量创建Pod

创建pod时指定运行命令。替换镜像中CMD的命令

  • 方式一
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    ┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
    └─$kubectl run comm-pod --image=nginx --image-pull-policy=IfNotPresent --dry-run=client -o yaml -- "echo liruilong"
    apiVersion: v1
    kind: Pod
    metadata:
      creationTimestamp: null
      labels:
        run: comm-pod
      name: comm-pod
    spec:
      containers:
      - args:
        - echo liruilong
        image: nginx
        imagePullPolicy: IfNotPresent
        name: comm-pod
        resources: {}
      dnsPolicy: ClusterFirst
      restartPolicy: Always
    status: {}
  • 方式二
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    ┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
    └─$kubectl run comm-pod --image=nginx --image-pull-policy=IfNotPresent --dry-run=client -o yaml -- sh -c "echo liruilong"
    apiVersion: v1
    kind: Pod
    metadata:
      creationTimestamp: null
      labels:
        run: comm-pod
      name: comm-pod
    spec:
      containers:
      - args:
        - sh
        - -c
        - echo liruilong
        image: nginx
        imagePullPolicy: IfNotPresent
        name: comm-pod
        resources: {}
      dnsPolicy: ClusterFirst
      restartPolicy: Always
    status: {}

kubectl delete -f comm-pod.yaml删除pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl run comm-pod --image=nginx --image-pull-policy=IfNotPresent --dry-run=client -o yaml -- sh c "echo liruilong"  > comm-pod.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply  -f comm-pod.yaml
pod/comm-pod created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl  delete  -f comm-pod.yaml
pod "comm-pod" deleted

批量创建pod

通过 sed 更改 pod名字的方式：sed ‘s/demo/demo1/‘ demo.yaml | kubectl apply -f -

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$sed 's/demo/demo1/' demo.yaml  | kubectl apply -f -
pod/demo1 created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$sed 's/demo/demo2/' demo.yaml  | kubectl create -f -
pod/demo2 created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide
NAME          READY   STATUS    RESTARTS   AGE     IP               NODE                         NOMINATED NODE   READINESS GATES
demo1         1/1     Running   0          3m29s   10.244.70.32     vms83.liruilongs.github.io   <none>           <none>
demo2         1/1     Running   0          3m6s    10.244.70.33     vms83.liruilongs.github.io   <none>           <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

容器共享pod的网络空间的。即使用同一个IP地址：pod IP

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.83 -m shell  -a "docker ps | grep demo1"
192.168.26.83 | CHANGED | rc=0 >>
0d644ad550f5   87a94228f133                                          "/docker-entrypoint.…"   8 minutes ago    Up 8 minutes              k8s_demo1_demo1_liruilong-pod-create_b721b109-a656-4379-9d3c-26710dadbf70_0
0bcffe0f8e2d   registry.aliyuncs.com/google_containers/pause:3.4.1   "/pause"                 8 minutes ago    Up 8 minutes              k8s_POD_demo1_liruilong-pod-create_b721b109-a656-4379-9d3c-26710dadbf70_0
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.83 -m shell  -a "docker inspect 0d644ad550f5 | grep -i ipaddress "
192.168.26.83 | CHANGED | rc=0 >>
            "SecondaryIPAddresses": null,
            "IPAddress": "",

pod多容器创建

一个pod内创建多个容器

comm-pod.yaml 文件编写

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: comm-pod
  name: comm-pod
spec:
  containers:
  - args:
    - sh
    - -c
    - echo liruilong;sleep 10000
    image: nginx
    imagePullPolicy: IfNotPresent
    name: comm-pod0
    resources: {}
  - name: comm-pod1
    image: nginx
    imagePullPolicy: IfNotPresent
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

创建 多容器pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl  apply  -f comm-pod.yaml
pod/comm-pod created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl  get pods
NAME          READY   STATUS    RESTARTS   AGE
comm-pod      2/2     Running   0          20s

镜像的下载策略

--image-pull-policy

  • Always 每次都下载最新镜像
  • Never 只使用本地镜像，从不下载
  • IfNotPresent 本地没有才下载

pod的重启策略

restartPolicy–单个容器正常退出

  • Always 总是重启
  • OnFailure 非正常退出才重启
  • Never 从不重启

labels 标签

k8s中每个资源对象都有标签

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get nodes --show-labels
NAME                         STATUS   ROLES                  AGE   VERSION   LABELS
vms81.liruilongs.github.io   Ready    control-plane,master   8d    v1.21.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=vms81.liruilongs.github.io,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=,node.kubernetes.io/exclude-from-external-load-balancers=
vms82.liruilongs.github.io   Ready    <none>                 8d    v1.21.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=vms82.liruilongs.github.io,kubernetes.io/os=linux
vms83.liruilongs.github.io   Ready    <none>                 8d    v1.21.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=vms83.liruilongs.github.io,kubernetes.io/os=linux
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods --show-labels
NAME        READY   STATUS    RESTARTS   AGE   LABELS
podcommon   1/1     Running   0          87s   name=liruilong

查看标签

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl  get pods --show-labels
NAME          READY   STATUS    RESTARTS   AGE     LABELS
comm-pod      2/2     Running   0          4m43s   run=comm-pod
mysql-577h7   1/1     Running   0          93m     app=mysql
myweb-4xlc5   1/1     Running   0          92m     app=myweb
myweb-ltqdt   1/1     Running   0          91m     app=myweb

指定标签过滤

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl  get pods -l run=comm-pod
NAME       READY   STATUS    RESTARTS   AGE
comm-pod   2/2     Running   0          5m12s
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

pod的状态

pod的状态 –
Pending pod 因为其他的原因导致pod准备开始创建 还没有创建(卡住了)
Running pod 已经被调度到节点上，且容器工作正常
Completed pod 里所有容器正常退出
error/CrashLoopBackOff 创建的时候就出错，属于内部原因
imagePullBackoff 创建pod的时候，镜像下载失败

三、Pod的基本操作

在pod里执行命令，查看pod详细信息。查看pod日志

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kubectl exec 命令
kubectl exec -it pod sh #如果pod里有多个容器，则命令是在第一个容器里执行
kubectl exec -it demo -c demo1 sh  # 指定容器
kubectl describe pod pod名
kubectl logs pod名 -c 容器名 #如果有多个容器的话 查看日志。
kubectl edit pod pod名 # 部分可以修改，有些不能修改

查看pod详细信息

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl describe  pod demo1
Name:         demo1
Namespace:    liruilong-pod-create
Priority:     0
Node:         vms83.liruilongs.github.io/192.168.26.83
Start Time:   Wed, 20 Oct 2021 22:27:15 +0800
Labels:       run=demo1
Annotations:  cni.projectcalico.org/podIP: 10.244.70.32/32
              cni.projectcalico.org/podIPs: 10.244.70.32/32
Status:       Running
IP:           10.244.70.32
IPs:
  IP:  10.244.70.32
Containers:
  demo1:
    Container ID:   docker://0d644ad550f59029036fd73d420d4d2c651801dd12814bb26ad8e979dc0b59c1
    Image:          nginx
    Image ID:       docker-pullable://nginx@sha256:644a70516a26004c97d0d85c7fe1d0c3a67ea8ab7ddf4aff193d9f301670cf36
    Port:           <none>
    Host Port:      <none>
    State:          Running
      Started:      Wed, 20 Oct 2021 22:27:20 +0800
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-scc89 (ro)
Conditions:
  Type              Status
  Initialized       True
  Ready             True
  ContainersReady   True
  PodScheduled      True
Volumes:
  kube-api-access-scc89:
    Type:                    Projected (a volume that contains injected data from multiple sources)
    TokenExpirationSeconds:  3607
    ConfigMapName:           kube-root-ca.crt
    ConfigMapOptional:       <nil>
    DownwardAPI:             true
QoS Class:                   BestEffort
Node-Selectors:              <none>
Tolerations:                 node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                             node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type    Reason     Age   From               Message
  ----    ------     ----  ----               -------
  Normal  Scheduled  13m   default-scheduler  Successfully assigned liruilong-pod-create/demo1 to vms83.liruilongs.github.io
  Normal  Pulled     13m   kubelet            Container image "nginx" already present on machine
  Normal  Created    13m   kubelet            Created container demo1
  Normal  Started    13m   kubelet            Started container demo1

在pod里执行命令

kubectl exec -it demo1 -- ls /tmp

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl exec -it demo1 -- sh
# ls
bin   dev                  docker-entrypoint.sh  home  lib64  mnt  proc  run   srv  tmp  var
boot  docker-entrypoint.d  etc                   lib   media  opt  root  sbin  sys  usr
# exit
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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl exec -it demo1 -- bash
root@demo1:/# ls
bin   dev                  docker-entrypoint.sh  home  lib64  mnt  proc  run   srv  tmp  var
boot  docker-entrypoint.d  etc                   lib   media  opt  root  sbin  sys  usr
root@demo1:/# exit
exit

Pod多个容器需要用-c指定

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl exec  comm-pod -c comm-pod1 -- echo liruilong
liruilong
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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl exec -it  comm-pod -c comm-pod1 -- sh
# ls
bin  boot  dev  docker-entrypoint.d  docker-entrypoint.sh  etc  home  lib  lib64  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var
# exit
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$#

查看日志

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl logs demo1
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2021/10/20 14:27:21 [notice] 1#1: using the "epoll" event method
2021/10/20 14:27:21 [notice] 1#1: nginx/1.21.3
2021/10/20 14:27:21 [notice] 1#1: built by gcc 8.3.0 (Debian 8.3.0-6)
2021/10/20 14:27:21 [notice] 1#1: OS: Linux 3.10.0-693.el7.x86_64
2021/10/20 14:27:21 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2021/10/20 14:27:21 [notice] 1#1: start worker processes
2021/10/20 14:27:21 [notice] 1#1: start worker process 32
2021/10/20 14:27:21 [notice] 1#1: start worker process 33
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

拷贝文件

和docke一样的，可以相互拷贝

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl  cp /etc/hosts  comm-pod:/usr/share/nginx/html -c  comm-pod1
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl exec  comm-pod -c comm-pod1 -- ls /usr/share/nginx/html
50x.html
hosts
index.html

pod里运行命令

command的执行方式一：

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apiVersion: v1
kind: Pod
metadata:
  name: myapp-pod
  labels:
    app: myapp
spec:
  containers: 
  - name: myapp-container
    image: busybox
    command: ['sh', '-c', 'echo OK! && sleep 60']

command的执行方式二：

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apiVersion: v1
kind: Pod
metadata:
  name: myapp-pod
  labels:
    app: myapp
spec:
  containers: 
  - name: myapp-container
    image: busybox
    command: 
    - sh
    - -c
    - echo OK! && sleep 60

优雅的关闭pod:pod的延期删除

k8s对于pod的删除有一个延期的删除期，即宽限期，这个时间默认为30s,如果删除时加了 --force选项，就会强制删除。

在删除宽限期内，节点状态被标记为treminating ,宽限期结束后删掉pod，这里的宽限期通过参数 terminationGracePeriodSeconds 设定

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl explain pod.spec
....
  terminationGracePeriodSeconds        <integer>
   pod需要优雅终止的可选持续时间(以秒为单位)。可在删除请求中增加。值必须是非负整数。
   值0表示通过kill信号立即停止(没有机会关机)。如果该值为null，则使用默认的宽限期。
   宽限期是在pod中运行的进程收到终止信号后的持续时间(以秒为单位)，以及进程被kill信号强制停止的时间。
   设置此值比流程的预期清理时间长。默认为30秒。

如果pod里面是Nginx进程，就不行，Nginx的处理信号的方式和k8s不同，当我们使用Nginx作为镜像来生成一个个pod的时候，pod里面的Nginx进程就会被很快的关闭，之后的pod也会被删除，并不会使用k8s的宽限期

terminationGracePeriodSeconds: 600

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: demo
  name: demo
spec:
  terminationGracePeriodSeconds: 600
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: demo
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

当某个pod正在被使用是，突然关闭，那这个时候我们还想处理一些事情，这里可以用 pod hook

pod生命周期

pod hook(钩子)

hook是一个很常见的功能，有时候也称回调，即在到达某一预期事件时触发的操作，比如 前端框架 Vue 的生命周期回调函数，java 虚拟机 JVM 在进程结束时的钩子线程。

在pod的整个生命周期内，有两个回调可以使用

两个回调可以使用
postStart： 当创建pod的时候调用，会随着pod里的主进程同时运行，并行操作，没有先后顺序
preStop： 当删除pod的时候创建，要先运行perStop里的程序，之后在关闭pod,这里的preStop必须是在pod的宽限期内完成，没有完成pod也会被强制删除

修改yaml文件:demo.yaml

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: demo
  name: demo
spec:
  terminationGracePeriodSeconds: 600
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: demo
    resources: {}
    lifecycle:
      postStart:
        exec:
          command: ["bin/sh", "-c","echo liruilong`date` >> /liruilong"]
      preStop:
        exec:
          command: ["bin/sh","-c","use/sbin/nginx -s quit"]
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

下面我们创建一个带钩子的pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl  apply  -f demo.yaml
pod/demo created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods
NAME          READY   STATUS    RESTARTS   AGE
demo          1/1     Running   0          21s
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl exec -it demo  -- bin/bash
root@demo:/# ls
bin   dev                  docker-entrypoint.sh  home  lib64      media  opt   root  sbin  sys  usr
boot  docker-entrypoint.d  etc                   lib   liruilong  mnt    proc  run   srv   tmp  var
root@demo:/# cat liruilong
liruilongSun Nov 14 05:10:51 UTC 2021
root@demo:/#

这里关闭的话，主进程不会等到宽限期结束，会找Ngixn收到关闭信号时直接关闭

四、初始化Pod

所谓初始化pod，类比java中的构造概念，如果pod的创建命令类比java的构造函数的话，那么初始化容器即为构造块，java中构造块是在构造函数之前执行的一些语句块。初始化容器即为主容器构造前执行的一些语句

初始化规则:
它们总是运行到完成。
每个都必须在下一个启动之前成功完成。
如果 Pod 的 Init 容器失败，Kubernetes 会不断地重启该 Pod，直到 Init 容器成功为止。然而，如果 Pod 对应的restartPolicy 为 Never，它不会重新启动。
Init 容器支持应用容器的全部字段和特性，但不支持 Readiness Probe，因为它们必须在 Pod 就绪之前运行完成。
如果为一个 Pod 指定了多个 Init 容器，那些容器会按顺序一次运行一个。 每个 Init 容器必须运行成功，下一个才能够运行。
因为Init容器可能会被重启、重试或者重新执行，所以 Init 容器的代码应该是幂等的。 特别地，被写到EmptyDirs 中文件的代码，应该对输出文件可能已经存在做好准备。
在 Pod 上使用 activeDeadlineSeconds，在容器上使用 livenessProbe，这样能够避免Init容器一直失败。 这就为 Init 容器活跃设置了一个期限。
在Pod中的每个 app 和Init容器的名称必须唯一；与任何其它容器共享同一个名称，会在验证时抛出错误。
对 Init 容器 spec 的修改，被限制在容器 image 字段中。 更改 Init 容器的image字段，等价于重启该 Pod。

初始化容器在pod资源文件里 的initContainers里定义，和containers是同一级

通过初始化容器修改内核参数

创建初始化容器，这里我们通过初始化容器修改swap的一个内核参数为0，即使用交换分区频率为0

Alpine 操作系统是一个面向安全的轻型 Linux 发行版。它不同于通常 Linux 发行版，Alpine 采用了 musl libc 和 busybox 以减小系统的体积和运行时资源消耗，但功能上比 busybox 又完善的多，因此得到开源社区越来越多的青睐。在保持瘦身的同时，Alpine 还提供了自己的包管理工具 apk，可以通过 https://pkgs.alpinelinux.org/packages 网站上查询包信息，也可以直接通过 apk 命令直接查询和安装各种软件

YAML文件编写

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod-init
  name: pod-init
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: pod1-init
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
  initContainers:
  - image: alpine
    name: init
    imagePullPolicy: IfNotPresent
    command: ["/bin/sh","-c","sbin/sysctl -w vm.swappiness=0"]
    securityContext:
      privileged: true
status: {}

查看系统默认值，运行pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$cat /proc/sys/vm/swappiness
30

创建初始化容器

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply  -f pod_init.yaml
pod/pod-init created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pod -o wide
NAME          READY   STATUS    RESTARTS   AGE    IP               NODE                         NOMINATED NODE   READINESS GATES
pod-init      1/1     Running   0          11m    10.244.70.54     vms83.liruilongs.github.io   <none>           <none>

pod创建成功验证一下

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$cd ..
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible 192.168.26.83 -m shell -a "cat /proc/sys/vm/swappiness"
192.168.26.83 | CHANGED | rc=0 >>
0

初始化容器和普通容器数据共享

配置文件编写

这里我们配置一个共享卷，然后再初始化容器里同步数据到普通的容器里。

pod_init1.yaml

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod-init1
  name: pod-init1
spec:
  volumes:
  - name: workdir
    emptyDir: {}
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: pod1-init
    resources: {}
    volumeMounts:
    - name: workdir
      mountPath: "/2021"
  dnsPolicy: ClusterFirst
  restartPolicy: Always
  initContainers:
  - image: busybox
    name: init
    imagePullPolicy: IfNotPresent
    command: ["/bin/sh","-c","touch /work-dir/liruilong.txt"]
    volumeMounts:
    - name: workdir
      mountPath: "work-dir"
status: {}

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply -f  pod_init1.yaml
pod/pod-init1 created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods pod-init1
NAME        READY   STATUS    RESTARTS   AGE
pod-init1   1/1     Running   0          30s
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl exec -it pod-init1 /bin/sh
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Defaulted container "pod1-init" out of: pod1-init, init (init)
# ls
2021  boot  docker-entrypoint.d   etc   lib    media  opt   root  sbin  sys  usr
bin   dev   docker-entrypoint.sh  home  lib64  mnt    proc  run   srv   tmp  var
# cd 2021;ls
liruilong.txt
#

五、静态pod

正常情况下，pod是在master上统一管理的,所谓静态pod就是，即不是由master上创建调度的，是属于node自身特的pod，在node上只要启动kubelet之后，就会自动的创建的pod。这里理解的话，结合java静态熟悉，静态方法理解，即的node节点初始化的时候需要创建的一些pod

比如 kubeadm的安装k8s的话，所以的服务都是通过容器的方式运行的。相比较二进制的方式方便很多,这里的话，那么涉及到master节点的相关组件在没有k8s环境时是如何运行，构建master节点的，这里就涉及到静态pod的问题。

工作节点创建 静态pod

工作节点查看kubelet 启动参数配置文件

/usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf
--pod-manifest-path=/etc/kubernetes/kubelet.d
在这里插入图片描述
Environment="KUBELET_KUBECONFIG_ARGS=--bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --pod-manifest-path=/etc/kubernetes/kubelet.d"
mkdir -p /etc/kubernetes/kubelet.d

首先需要在配置文件中添加加载静态pod 的yaml文件位置
先在本地改配置文件，使用ansible发送到node节点上，

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cat /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf
# Note: This dropin only works with kubeadm and kubelet v1.11+
[Service]
Environment="KUBELET_KUBECONFIG_ARGS=--bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --pod-manifest-path=/etc/kubernetes/kubelet.d"
Environment="KUBELET_CONFIG_ARGS=--config=/var/lib/kubelet/config.yaml"
# This is a file that "kubeadm init" and "kubeadm join" generates at runtime, populating the KUBELET_KUBEADM_ARGS variable dynamically
EnvironmentFile=-/var/lib/kubelet/kubeadm-flags.env
# This is a file that the user can use for overrides of the kubelet args as a last resort. Preferably, the user should use
# the .NodeRegistration.KubeletExtraArgs object in the configuration files instead. KUBELET_EXTRA_ARGS should be sourced from this file.
EnvironmentFile=-/etc/sysconfig/kubelet
ExecStart=
ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$mkdir -p /etc/kubernetes/kubelet.d

修改配置后需要加载配置文件重启kubelet

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible node -m  copy  -a "src=/usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf dest=/usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf force
=yes"
192.168.26.82 | CHANGED => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": true,
    "checksum": "13994d828e831f4aa8760c2de36e100e7e255526",
    "dest": "/usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf",
    "gid": 0,
    "group": "root",
    "md5sum": "0cfe0f899ea24596f95aa2e175f0dd08",
    "mode": "0644",
    "owner": "root",
    "size": 946,
    "src": "/root/.ansible/tmp/ansible-tmp-1637403640.92-32296-63660481173900/source",
    "state": "file",
    "uid": 0
}
192.168.26.83 | CHANGED => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": true,
    "checksum": "13994d828e831f4aa8760c2de36e100e7e255526",
    "dest": "/usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf",
    "gid": 0,
    "group": "root",
    "md5sum": "0cfe0f899ea24596f95aa2e175f0dd08",
    "mode": "0644",
    "owner": "root",
    "size": 946,
    "src": "/root/.ansible/tmp/ansible-tmp-1637403640.89-32297-164984088437265/source",
    "state": "file",
    "uid": 0
}

创建配置文件文件夹

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible node -m  shell -a "mkdir -p /etc/kubernetes/kubelet.d"
192.168.26.83 | CHANGED | rc=0 >>

192.168.26.82 | CHANGED | rc=0 >>

加载配置文件

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible node -m  shell -a "systemctl daemon-reload"
192.168.26.82 | CHANGED | rc=0 >>

192.168.26.83 | CHANGED | rc=0 >>

重启kubelet

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible node -m  shell -a "systemctl restart kubelet"
192.168.26.83 | CHANGED | rc=0 >>

192.168.26.82 | CHANGED | rc=0 >>

现在我们需要到Node的/etc/kubernetes/kubelet.d里创建一个yaml文件，然后根据这个yaml文件，创建一个pod，这样创建出来的node，是不会接受master的管理的。我们同样使用ansible的方式来处理

配置文件编写

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cat static-pod.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod-static
  name: pod-static
  namespeace: default
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: pod-demo
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

default名称空间里创建两个静态pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible node -m copy -a "src=./static-pod.yaml dest=/etc/kubernetes/kubelet.d/static-pod.yaml"
192.168.26.83 | CHANGED => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": true,
    "checksum": "9b059b0acb4cd99272809d1785926092816f8771",
    "dest": "/etc/kubernetes/kubelet.d/static-pod.yaml",
    "gid": 0,
    "group": "root",
    "md5sum": "41515d4c5c116404cff9289690cdcc20",
    "mode": "0644",
    "owner": "root",
    "size": 302,
    "src": "/root/.ansible/tmp/ansible-tmp-1637474358.05-72240-139405051351544/source",
    "state": "file",
    "uid": 0
}
192.168.26.82 | CHANGED => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": true,
    "checksum": "9b059b0acb4cd99272809d1785926092816f8771",
    "dest": "/etc/kubernetes/kubelet.d/static-pod.yaml",
    "gid": 0,
    "group": "root",
    "md5sum": "41515d4c5c116404cff9289690cdcc20",
    "mode": "0644",
    "owner": "root",
    "size": 302,
    "src": "/root/.ansible/tmp/ansible-tmp-1637474357.94-72238-185516913523170/source",
    "state": "file",
    "uid": 0
}

node检查一下，配置文件

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible node -m shell -a " cat /etc/kubernetes/kubelet.d/static-pod.yaml"
192.168.26.83 | CHANGED | rc=0 >>
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod-static
  name: pod-static
  namespeace: default
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: pod-demo
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}
192.168.26.82 | CHANGED | rc=0 >>
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod-static
  name: pod-static
  namespeace: default
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: pod-demo
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

查看静态pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl get pod -n default
NAME                                    READY   STATUS    RESTARTS   AGE
pod-static-vms82.liruilongs.github.io   1/1     Running   0          8m17s
pod-static-vms83.liruilongs.github.io   1/1     Running   0          9m3s
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible node -m shell -a "rm -rf /etc/kubernetes/kubelet.d/static-pod.yaml"

master 节点创建pod

这里我们换一种方式创建一个pod，通过 KUBELET_CONFIG_ARGS=--config=/var/lib/kubelet/config.yaml中定义的静态pod位置的方式创建pod

这里需要注意的是如果master 节点是使用 --pod-manifest-path=/etc/kubernetes/kubelet.d的方式的话，k8s就会无法启动，因为--pod-manifest-path会覆盖staticPodPath: /etc/kubernetes/manifests。

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cat /usr/lib/systemd/system/kubelet.service.d/10-kubeadm.conf
# Note: This dropin only works with kubeadm and kubelet v1.11+
[Service]
Environment="KUBELET_KUBECONFIG_ARGS=--bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf "
Environment="KUBELET_CONFIG_ARGS=--config=/var/lib/kubelet/config.yaml"
# This is a file that "kubeadm init" and "kubeadm join" generates at runtime, populating the KUBELET_KUBEADM_ARGS variable dynamically
EnvironmentFile=-/var/lib/kubelet/kubeadm-flags.env
# This is a file that the user can use for overrides of the kubelet args as a last resort. Preferably, the user should use
# the .NodeRegistration.KubeletExtraArgs object in the configuration files instead. KUBELET_EXTRA_ARGS should be sourced from this file.
EnvironmentFile=-/etc/sysconfig/kubelet
ExecStart=
ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$grep static /var/lib/kubelet/config.yaml
staticPodPath: /etc/kubernetes/manifests
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

/etc/kubernetes/manifests/ 里面放着k8s环境需要的一些静态pod组件

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ls -l  /etc/kubernetes/manifests/
总用量 16
-rw------- 1 root root 2284 10月 19 00:09 etcd.yaml
-rw------- 1 root root 3372 10月 19 00:10 kube-apiserver.yaml
-rw------- 1 root root 2893 10月 19 00:10 kube-controller-manager.yaml
-rw------- 1 root root 1479 10月 19 00:10 kube-scheduler.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

直接copy之前的配置文件在master节点创建静态pod，并检查

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cp static-pod.yaml /etc/kubernetes/manifests/static-pod.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl get pods -n default
NAME                                    READY   STATUS    RESTARTS   AGE
pod-static-vms81.liruilongs.github.io   1/1     Running   0          13s
pod-static-vms82.liruilongs.github.io   1/1     Running   0          34m
pod-static-vms83.liruilongs.github.io   1/1     Running   0          35m
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$rm -rf /etc/kubernetes/manifests/static-pod.yaml

六、Pod调度

调度的三个对象

待调度Pod列表:有多少个pod需要调度，即创建的pod列表

可用node列表:有那些节点可以参与调度，排除有污点，端口的一些node

调度算法

  • 主机过滤
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    + `NoDiskConflict`
    + `PodFitsResources`
    + `PodFitsPorts`
    + `MatchNodeSelector`
    + `HostName`
    + `NoVolumeZoneConflict`
    + `PodToleratesNodeTaints`
    + `CheckNodeMemoryPressure`
    + `CheckNodeDiskPressure`
    + `MaxEBSVolumeCount`
    + `MaxGCEPDVolumeCount`
    + `MaxAzureDiskVolumeCount`
    + `MatchInterPodAffinity`
    + `GeneralPredicates`
    + `NodeVolumeNodeConflic`
  • 主机打分
分数项 公式
LeastRequestedPriority score=cpu ( ( capacity - sum ( requested ) ) * 10 / capacity) + memory ( ( capacity - sum ( requested) ) * 10 / capacity )/2
BalanceResourceAllocation score = 10 -abs ( cpuFraction - memoryFraction ) * 10
CalculateSpreadPriority Score = 10 * ((maxCount -counts)/ (maxCount))

手动指定pod的运行位置:

可以给node设置指定的标签，然后我们可以在创建pod里指定node标签

标签设置 –
查看 kubectl get nodes –show-labels
设置 kubectl label node node2 disktype=ssd
取消 kubectl label node node2 disktype
所有节点设置 kubectl label node all key=vale

查看节点pod：kubectl get node --show-labels

给节点设置标签

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl label node vms82.liruilongs.github.io disktype=node1
node/vms82.liruilongs.github.io labeled
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl label node vms83.liruilongs.github.io disktype=node2
node/vms83.liruilongs.github.io labeled
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl get node --show-labels
NAME                         STATUS   ROLES                  AGE   VERSION   LABELS
vms81.liruilongs.github.io   Ready    control-plane,master   45d   v1.22.2   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=vms81.liruilongs.github.io,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=,node.kubernetes.io/exclude-from-external-load-balancers=
vms82.liruilongs.github.io   Ready    <none>                 45d   v1.22.2   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=node1,kubernetes.io/arch=amd64,kubernetes.io/hostname=vms82.liruilongs.github.io,kubernetes.io/os=linux
vms83.liruilongs.github.io   Ready    <none>                 45d   v1.22.2   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=node2,kubernetes.io/arch=amd64,kubernetes.io/hostname=vms83.liruilongs.github.io,kubernetes.io/os=linux
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

特殊的内置标签node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=,用于设置角色列roles

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl get node
NAME                         STATUS   ROLES                  AGE   VERSION
vms81.liruilongs.github.io   Ready    control-plane,master   45d   v1.22.2
vms82.liruilongs.github.io   Ready    <none>                 45d   v1.22.2
vms83.liruilongs.github.io   Ready    <none>                 45d   v1.22.2

我们也可以做worker节点上设置

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl label nodes vms82.liruilongs.github.io node-role.kubernetes.io/worker1=
node/vms82.liruilongs.github.io labeled
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl label nodes vms83.liruilongs.github.io node-role.kubernetes.io/worker2=
node/vms83.liruilongs.github.io labeled
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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl get node
NAME                         STATUS   ROLES                  AGE   VERSION
vms81.liruilongs.github.io   Ready    control-plane,master   45d   v1.22.2
vms82.liruilongs.github.io   Ready    worker1                45d   v1.22.2
vms83.liruilongs.github.io   Ready    worker2                45d   v1.22.2
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

选择器(nodeSelector)方式

在特定节点上运行pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get nodes -l disktype=node2
NAME                         STATUS   ROLES     AGE   VERSION
vms83.liruilongs.github.io   Ready    worker2   45d   v1.22.2
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$vim pod-node2.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply  -f pod-node2.yaml
pod/podnode2 created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -owide
NAME       READY   STATUS    RESTARTS   AGE   IP               NODE                         NOMINATED NODE   READINESS GATES
podnode2   1/1     Running   0          13m   10.244.70.60     vms83.liruilongs.github.io   <none>           <none>

pod-node2.yaml

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: podnode2
  name: podnode2
spec:
  nodeSelector:
    disktype: node2
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: podnode2
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

指定节点名称(nodeName)的方式

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$vim pod-node1.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply -f pod-node1.yaml
pod/podnode1 created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -owide
NAME       READY   STATUS    RESTARTS   AGE   IP               NODE                         NOMINATED NODE   READINESS GATES
podnode1   1/1     Running   0          36s   10.244.171.165   vms82.liruilongs.github.io   <none>           <none>
podnode2   1/1     Running   0          13m   10.244.70.60     vms83.liruilongs.github.io   <none>           <none>

pod-node1.yaml

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: podnode1
  name: podnode1
spec:
  nodeName: vms82.liruilongs.github.io
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: podnode1
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

当pod资源文件指定的节点标签,或者节点名不存在时，这个pod资源是无法创建成功的

主机亲和性

所谓主机亲和性，即在满足指定条件的节点上运行。分为硬策略(必须满足)，软策略(最好满足)

硬策略(requiredDuringSchedulingIgnoredDuringExecution)

pod-node-a.yaml

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: podnodea
  name: podnodea
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: podnodea
    resources: {}
  affinity:
    nodeAffinity: #主机亲和性
      requiredDuringSchedulingIgnoredDuringExecution: #硬策略
        nodeSelectorTerms:
        - matchExpressions:
          - key: kubernetes.io/hostname
            operator: In
            values:
            - vms85.liruilongs.github.io
            - vms84.liruilongs.github.io
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

条件不满足，所以 Pending

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply -f pod-node-a.yaml
pod/podnodea created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods
NAME       READY   STATUS    RESTARTS   AGE
podnodea   0/1     Pending   0          8s

我梦修改一下

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$sed -i  's/vms84.liruilongs.github.io/vms83.liruilongs.github.io/' pod-node-a.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply -f pod-node-a.yaml
pod/podnodea created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -owide
NAME       READY   STATUS    RESTARTS   AGE   IP             NODE                         NOMINATED NODE   READINESS GATES
podnodea   1/1     Running   0          13s   10.244.70.61   vms83.liruilongs.github.io   <none>           <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

软策略(preferredDuringSchedulingIgnoredDuringExecution)

pod-node-a-r.yaml

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: podnodea
  name: podnodea
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: podnodea
    resources: {}
  affinity:
    nodeAffinity: #主机亲和性
      preferredDuringSchedulingIgnoredDuringExecution: # 软策略
      - weight: 2
        preference:
          matchExpressions:
          - key: kubernetes.io/hostname
            operator: In
            values:
            - vms85.liruilongs.github.io
            - vms84.liruilongs.github.io
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

检查一下

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$vim pod-node-a-r.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply -f  pod-node-a-r.yaml
pod/podnodea created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -owide
NAME       READY   STATUS    RESTARTS   AGE   IP             NODE                         NOMINATED NODE   READINESS GATES
podnodea   1/1     Running   0          28s   10.244.70.62   vms83.liruilongs.github.io   <none>           <none>

运算符 描述
In 包含自, 比如上面的硬亲和就包含env_role=dev、env_role=test两种标签
NotIn 和上面相反，凡是包含该标签的节点都不会匹配到
Exists 存在里面和In比较类似，凡是有某个标签的机器都会被选择出来。使用Exists的operator的话，values里面就不能写东西了。
Gt greater than的意思，表示凡是某个value大于设定的值的机器则会被选择出来。
Lt less than的意思，表示凡是某个value小于设定的值的机器则会被选择出来。
DoesNotExists 不存在该标签的节点

Annotations 的设置

Annotations 即注释，设置查看方式很简单

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl annotate nodes vms82.liruilongs.github.io "dest=这是一个工作节点"
node/vms82.liruilongs.github.io annotated
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl describe nodes vms82.liruilongs.github.io
Name:               vms82.liruilongs.github.io
Roles:              worker1
Labels:             beta.kubernetes.io/arch=amd64
                    beta.kubernetes.io/os=linux
                    disktype=node1
                    kubernetes.io/arch=amd64
                    kubernetes.io/hostname=vms82.liruilongs.github.io
                    kubernetes.io/os=linux
                    node-role.kubernetes.io/worker1=
Annotations:        dest: 这是一个工作节点
                    kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock
                    node.alpha.kubernetes.io/ttl: 0
                    projectcalico.org/IPv4Address: 192.168.26.82/24
                    projectcalico.org/IPv4IPIPTunnelAddr: 10.244.171.128
                    volumes.kubernetes.io/controller-managed-attach-detach: true

七、节点的coedon与drain

如果想把某个节点设置为不可用的话，可以对节点实施cordon或者drain

如果一个node被标记为cordon，新创建的pod不会被调度到此node上，已经调度上去的不会被移走

coedon用于节点的维护，当不希望再节点分配pod，那么可以使用coedon把节点标记为不可调度。

这里我们为了方便，创建一个Deployment控制器用去用于演示，关于Deployment，可以简单理解为他能保证你的pod保持在一定数量，当pod挂掉事，

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl create deployment nginx  --image=nginx  --dry-run=client -o yaml >nginx-dep.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cp nginx-dep.yaml  ./k8s-pod-create/nginx-dep.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$cd k8s-pod-create/
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$vim nginx-dep.yaml

nginx-dep.yaml

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apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: nginx
  name: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        name: nginx
        imagePullPolicy: IfNotPresent
        resources: {}
status: {}

创建 deploy资源

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply  -f nginx-dep.yaml
deployment.apps/nginx created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -owide
NAME                     READY   STATUS    RESTARTS   AGE     IP               NODE
      NOMINATED NODE   READINESS GATES
nginx-7cf7d6dbc8-hx96s   1/1     Running   0          2m16s   10.244.171.167   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-wshxp   1/1     Running   0          2m16s   10.244.70.1      vms83.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-x78x4   1/1     Running   0          2m16s   10.244.70.63     vms83.liruilongs.github.io   <none>           <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

节点的coedon

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kubectl cordon vms83.liruilongs.github.io  #标记不可用
kubectl uncordon vms83.liruilongs.github.io #取消标记

通过cordon把vms83.liruilongs.github.io标记为不可调度

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl cordon vms83.liruilongs.github.io  #通过cordon把83标记为不可调度
node/vms83.liruilongs.github.io cordoned

查看节点状态，vms83.liruilongs.github.io变成SchedulingDisabled

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get nodes
NAME                         STATUS                     ROLES                  AGE   VERSION
vms81.liruilongs.github.io   Ready                      control-plane,master   48d   v1.22.2
vms82.liruilongs.github.io   Ready                      worker1                48d   v1.22.2
vms83.liruilongs.github.io   Ready,SchedulingDisabled   worker2                48d   v1.22.2

修改deployment副本数量 –replicas=6 

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl scale deployment nginx  --replicas=6
deployment.apps/nginx scaled

新增的pod都调度到了vms82.liruilongs.github.io 节点

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide
NAME                     READY   STATUS    RESTARTS   AGE     IP               NODE                         NOMINATED NODE   READINESS GATES
nginx-7cf7d6dbc8-2nmsj   1/1     Running   0          64s     10.244.171.170   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-chsrn   1/1     Running   0          63s     10.244.171.168   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-hx96s   1/1     Running   0          7m30s   10.244.171.167   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-lppbp   1/1     Running   0          63s     10.244.171.169   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-wshxp   1/1     Running   0          7m30s   10.244.70.1      vms83.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-x78x4   1/1     Running   0          7m30s   10.244.70.63     vms83.liruilongs.github.io   <none>           <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

把vms83.liruilongs.github.io节点上的Nginx都干掉，会发现新增pod都调度到了vms82.liruilongs.github.io

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl delete pod nginx-7cf7d6dbc8-wshxp
pod "nginx-7cf7d6dbc8-wshxp" deleted
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide
NAME                     READY   STATUS    RESTARTS   AGE     IP               NODE                         NOMINATED NODE   READINESS GATES
nginx-7cf7d6dbc8-2nmsj   1/1     Running   0          2m42s   10.244.171.170   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-5hnc7   1/1     Running   0          10s     10.244.171.171   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-chsrn   1/1     Running   0          2m41s   10.244.171.168   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-hx96s   1/1     Running   0          9m8s    10.244.171.167   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-lppbp   1/1     Running   0          2m41s   10.244.171.169   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-x78x4   1/1     Running   0          9m8s    10.244.70.63     vms83.liruilongs.github.io   <none>           <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl delete pod nginx-7cf7d6dbc8-x78x4
pod "nginx-7cf7d6dbc8-x78x4" deleted
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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide
NAME                     READY   STATUS    RESTARTS   AGE     IP               NODE                         NOMINATED NODE   READINESS GATES
nginx-7cf7d6dbc8-2nmsj   1/1     Running   0          3m31s   10.244.171.170   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-5hnc7   1/1     Running   0          59s     10.244.171.171   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-chsrn   1/1     Running   0          3m30s   10.244.171.168   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-hx96s   1/1     Running   0          9m57s   10.244.171.167   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-lppbp   1/1     Running   0          3m30s   10.244.171.169   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-m8ltr   1/1     Running   0          30s     10.244.171.172   vms82.liruilongs.github.io   <none>           <none>

通过 uncordon恢复节点vms83.liruilongs.github.io状态

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl uncordon vms83.liruilongs.github.io #恢复节点状态
node/vms83.liruilongs.github.io uncordoned
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get nodes
NAME                         STATUS   ROLES                  AGE   VERSION
vms81.liruilongs.github.io   Ready    control-plane,master   48d   v1.22.2
vms82.liruilongs.github.io   Ready    worker1                48d   v1.22.2
vms83.liruilongs.github.io   Ready    worker2                48d   v1.22.2

删除所有的pod

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl scale deployment nginx --replicas=0
deployment.apps/nginx scaled
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide
No resources found in liruilong-pod-create namespace.

节点的为drain

如果一个节点被设置为drain，则此节点不再被调度pod，且此节点上已经运行的pod会被驱逐(evicted)到其他节点

drain包含两种状态：cordon不可被调度，evicted驱逐当前节点所以pod

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kubectl uncordon vms83.liruilongs.github.io

通过deployment添加4个nginx副本--replicas=4

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl scale deployment nginx --replicas=4
deployment.apps/nginx scaled
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide --one-output
NAME                     READY   STATUS    RESTARTS   AGE   IP               NODE                         NOMINATED NODE   READINESS GATES
nginx-7cf7d6dbc8-2clnb   1/1     Running   0          22s   10.244.171.174   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-9p6g2   1/1     Running   0          22s   10.244.70.2      vms83.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-ptqxm   1/1     Running   0          22s   10.244.171.173   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-zmdqm   1/1     Running   0          22s   10.244.70.4      vms83.liruilongs.github.io   <none>           <none>

添加一下污点 将节点vms82.liruilongs.github.io设置为drain

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl drain vms82.liruilongs.github.io --ignore-daemonsets --delete-emptydir-data
node/vms82.liruilongs.github.io cordoned
WARNING: ignoring DaemonSet-managed Pods: kube-system/calico-node-ntm7v, kube-system/kube-proxy-nzm24
evicting pod liruilong-pod-create/nginx-7cf7d6dbc8-ptqxm
evicting pod kube-system/metrics-server-bcfb98c76-wxv5l
evicting pod liruilong-pod-create/nginx-7cf7d6dbc8-2clnb
pod/nginx-7cf7d6dbc8-2clnb evicted
pod/nginx-7cf7d6dbc8-ptqxm evicted
pod/metrics-server-bcfb98c76-wxv5l evicted
node/vms82.liruilongs.github.io evicted
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get nodes
NAME                         STATUS                     ROLES                  AGE   VERSION
vms81.liruilongs.github.io   Ready                      control-plane,master   48d   v1.22.2
vms82.liruilongs.github.io   Ready,SchedulingDisabled   worker1                48d   v1.22.2
vms83.liruilongs.github.io   Ready                      worker2                48d   v1.22.2

查看节点调度，所有pod调度到了vms83.liruilongs.github.io这台机器

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide --one-output
NAME                     READY   STATUS    RESTARTS   AGE     IP            NODE                         NOMINATED NODE   READINESS GATES
nginx-7cf7d6dbc8-9p6g2   1/1     Running   0          4m20s   10.244.70.2   vms83.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-hkflr   1/1     Running   0          25s     10.244.70.5   vms83.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-qt48k   1/1     Running   0          26s     10.244.70.7   vms83.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-zmdqm   1/1     Running   0          4m20s   10.244.70.4   vms83.liruilongs.github.io   <none>           <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

取消污点：kubectl uncordon vms82.liruilongs.github.io

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl uncordon vms82.liruilongs.github.io
node/vms82.liruilongs.github.io uncordoned
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

报错的情况

将节点vms82.liruilongs.github.io设置为drain

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl drain vms82.liruilongs.github.io
node/vms82.liruilongs.github.io cordoned
DEPRECATED WARNING: Aborting the drain command in a list of nodes will be deprecated in v1.23.
The new behavior will make the drain command go through all nodes even if one or more nodes failed during the drain.
For now, users can try such experience via: --ignore-errors
error: unable to drain node "vms82.liruilongs.github.io", aborting command...

There are pending nodes to be drained:
 vms82.liruilongs.github.io
cannot delete DaemonSet-managed Pods (use --ignore-daemonsets to ignore): kube-system/calico-node-ntm7v, kube-system/kube-proxy-nzm24
cannot delete Pods with local storage (use --delete-emptydir-data to override): kube-system/metrics-server-bcfb98c76-wxv5l
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get nodes
NAME                         STATUS                     ROLES                  AGE   VERSION
vms81.liruilongs.github.io   Ready                      control-plane,master   48d   v1.22.2
vms82.liruilongs.github.io   Ready,SchedulingDisabled   worker1                48d   v1.22.2
vms83.liruilongs.github.io   Ready                      worker2                48d   v1.22.2

uncordon掉刚才的节点

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl uncordon vms82.liruilongs.github.io
node/vms82.liruilongs.github.io uncordoned
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get nodes
NAME                         STATUS   ROLES                  AGE   VERSION
vms81.liruilongs.github.io   Ready    control-plane,master   48d   v1.22.2
vms82.liruilongs.github.io   Ready    worker1                48d   v1.22.2
vms83.liruilongs.github.io   Ready    worker2                48d   v1.22.2

八、节点taint(污点)及pod的tolerations(容忍污点)

给节点设置及删除taint，设置operator的值为Equal，以及设置operator的值为Exists

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$ansible master -m shell -a "kubectl describe  nodes vms81.liruilongs.github.io | grep -E '(Roles|Taints)'"
192.168.26.81 | CHANGED | rc=0 >>
Roles:              control-plane,master
Taints:             node-role.kubernetes.io/master:NoSchedule

master节点从来没有调度到pod，因为master节点设置了污点，如果想要在某个被设置了污点的机器调度pod，那么pod需要设置tolerations(容忍污点)才能够被运行。

taint(污点)的设置和查看

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# 查看节点角色，和是否设置污点
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl describe  nodes vms82.liruilongs.github.io | grep -E '(Roles|Taints)'
Roles:              worker1
Taints:             <none>
# 给 vms83.liruilongs.github.io节点设置污点，指定key为key83
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl describe  nodes vms83.liruilongs.github.io | grep -E '(Roles|Taints)'
Roles:              worker2
Taints:             <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl taint node vms83.liruilongs.github.io key83=:NoSchedule
node/vms83.liruilongs.github.io tainted
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl describe  nodes vms83.liruilongs.github.io | grep -E '(Roles|Taints)' # 从新查看污点信息
Roles:              worker2
Taints:             key83:NoSchedule
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$

重新通过deployment 创建pod，会发现pod都调度到82上面，因为83设置了污点

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl scale deployment nginx --replicas=0
deployment.apps/nginx scaled
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl scale deployment nginx --replicas=4
deployment.apps/nginx scaled
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide --one-output
NAME                     READY   STATUS              RESTARTS   AGE   IP       NODE                         NOMINATED NODE   READINESS GATES
nginx-7cf7d6dbc8-dhst5   0/1     ContainerCreating   0          12s   <none>   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-j6g25   0/1     ContainerCreating   0          12s   <none>   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-wpnhr   0/1     ContainerCreating   0          12s   <none>   vms82.liruilongs.github.io   <none>           <none>
nginx-7cf7d6dbc8-zkww8   0/1     ContainerCreating   0          11s   <none>   vms82.liruilongs.github.io   <none>           <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl delete deployment nginx
deployment.apps "nginx" deleted

取消污点设置

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl taint node vms83.liruilongs.github.io key83-
node/vms83.liruilongs.github.io untainted
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl describe  nodes vms83.liruilongs.github.io | grep -E '(Roles|Taints)'
Roles:              worker2
Taints:             <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

设置operator的值为Equal

如果需要在有污点的节点上运行pod，那么需要在定义pod的时候指定toleration属性

在设置节点taint的时候，如果value的值为不为空，在pod里的tolerations字段只能写Equal，不能写Exists,

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl taint nodes  vms82.liruilongs.github.io key82=val82:NoSchedule
node/vms82.liruilongs.github.io tainted
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl describe  nodes vms82.liruilongs.github.io | grep -E '(Roles|Taints)'
Roles:              worker1
Taints:             key82=val82:NoSchedule
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

修改yaml文件 pod-taint3.yaml

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$cat pod-taint2.yaml > pod-taint3.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$vim  pod-taint3.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$cat pod-taint3.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod1
  name: pod1
spec:
  nodeSelector:
    disktype: node2
  tolerations:
  - key: "key82"
    operator: "Equal"
    value: "val82"
    effect: "NoSchedule"
  containers:
  - image: nginx
    name: pod1
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}
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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply -f pod-taint3.yaml
pod/pod1 created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide
NAME   READY   STATUS    RESTARTS   AGE   IP               NODE                         NOMINATED NODE   READINESS GATES
pod1   1/1     Running   0          11s   10.244.171.180   vms82.liruilongs.github.io   <none>           <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

设置operator的值为Exists

如果使用Exists的话，那么pod中不能写value

设置vms83.liruilongs.github.io 节点污点标记

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┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl taint node vms83.liruilongs.github.io key83=:NoSchedule
node/vms83.liruilongs.github.io tainted
┌──[root@vms81.liruilongs.github.io]-[~/ansible]
└─$kubectl describe  nodes vms83.liruilongs.github.io | grep -E '(Roles|Taints)'
Roles:              worker2
Taints:             key83:NoSchedule
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get nodes --show-labels
NAME                         STATUS   ROLES                  AGE   VERSION   LABELS
vms81.liruilongs.github.io   Ready    control-plane,master   48d   v1.22.2   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=vms81.liruilongs.github.io,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=,node.kubernetes.io/exclude-from-external-load-balancers=
vms82.liruilongs.github.io   Ready    worker1                48d   v1.22.2   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=node1,kubernetes.io/arch=amd64,kubernetes.io/hostname=vms82.liruilongs.github.io,kubernetes.io/os=linux,node-role.kubernetes.io/worker1=
vms83.liruilongs.github.io   Ready    worker2                48d   v1.22.2   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=node2,kubernetes.io/arch=amd64,kubernetes.io/hostname=vms83.liruilongs.github.io,kubernetes.io/os=linux,node-role.kubernetes.io/worker2=

pod-taint.yaml

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod1
  name: pod1
spec:
  nodeSelector:
    disktype: node2
  tolerations:
  - key: "key83"
    operator: "Exists"
    effect: "NoSchedule"
  containers:
  - image: nginx
    name: pod1
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

会发现节点调度到了有污点的vms83.liruilongs.github.io节点

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply -f pod-taint.yaml
pod/pod1 created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide
NAME   READY   STATUS    RESTARTS   AGE    IP            NODE                         NOMINATED NODE   READINESS GATES
pod1   1/1     Running   0          3m4s   10.244.70.8   vms83.liruilongs.github.io   <none>           <none>

当然，value没有值也可以这样使用Equal

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$cp pod-taint.yaml pod-taint2.yaml
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$vim pod-taint2.yaml

pod-taint2.yaml

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apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod1
  name: pod1
spec:
  nodeSelector:
    disktype: node2
  tolerations:
  - key: "key83"
    operator: "Equal"
    value: ""
    effect: "NoSchedule"
  containers:
  - image: nginx
    name: pod1
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

会发现节点还是调度到了有污点的vms83.liruilongs.github.io节点

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┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl  delete -f pod-taint.yaml
pod "pod1" deleted
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl apply -f pod-taint2.yaml
pod/pod1 created
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl get pods -o wide
NAME   READY   STATUS              RESTARTS   AGE   IP       NODE                         NOMINATED NODE   READINESS GATES
pod1   0/1     ContainerCreating   0          8s    <none>   vms83.liruilongs.github.io   <none>           <none>
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$kubectl taint nodes vms83.liruilongs.github.io key83-
node/vms83.liruilongs.github.io untainted
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-pod-create]
└─$

关于 Kubernetes中Pod的一些笔记

https://liruilongs.github.io/2021/11/25/K8s/API 学习/关于 Kubernetes中Pod的一些笔记/

发布于

2021-11-25

更新于

2023-06-21

许可协议

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