pod(三)：pod的管理

目录

• 一.系统环境
• 二.前言
• 三.pod的管理
  • 3.1 环境介绍
  • 3.2 管理pod

一.系统环境

服务器版本	docker软件版本	CPU架构
CentOS Linux release 7.4.1708 (Core)	Docker version 20.10.12	x86_64

二.前言

pod的常见管理。

管理pod的前提是已经有一套可以正常运行的Kubernetes集群，关于Kubernetes(k8s)集群的安装部署，可以查看博客《Centos7 安装部署Kubernetes(k8s)集群》https://www.cnblogs.com/renshengdezheli/p/16686769.html

三.pod的管理

3.1 环境介绍

Kubernetes集群架构：k8scloude1作为master节点，k8scloude2，k8scloude3作为worker节点

服务器	操作系统版本	CPU架构	进程	功能描述
k8scloude1/192.168.110.130	CentOS Linux release 7.4.1708 (Core)	x86_64	docker，kube-apiserver，etcd，kube-scheduler，kube-controller-manager，kubelet，kube-proxy，coredns，calico	k8s master节点
k8scloude2/192.168.110.129	CentOS Linux release 7.4.1708 (Core)	x86_64	docker，kubelet，kube-proxy，calico	k8s worker节点
k8scloude3/192.168.110.128	CentOS Linux release 7.4.1708 (Core)	x86_64	docker，kubelet，kube-proxy，calico	k8s worker节点

3.2 管理pod

使用Nginx镜像创建一个pod

[root@k8scloude1 pod]# vim nginx.yaml 

#kind: Pod表示资源类型为Pod   labels指定pod标签   metadata下面的name指定pod名字   containers下面全是容器的定义   
#image指定镜像名字  imagePullPolicy指定镜像下载策略   containers下面的name指定容器名
#resources指定容器资源（CPU，内存等）   env指定容器里的环境变量   dnsPolicy指定DNS策略
#restartPolicy容器重启策略    ports指定容器端口
[root@k8scloude1 pod]# cat nginx.yaml 
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: nginx
  name: nginx
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: nginx
    resources: {}
    ports:
    - name: http
      containerPort: 80
      protocol: TCP
    env:
    - name: xx
      value: "12"
    - name: yy
      value: "21"
    - name: zz
      value: hello
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

[root@k8scloude1 pod]# ls
nginx.yaml  pod1.yaml  pod2.yaml

[root@k8scloude1 pod]# kubectl apply -f nginx.yaml 
pod/nginx created

[root@k8scloude1 pod]# kubectl get pod
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          5s

不进入容器，执行ls / 命令

#不进入容器，执行命令：kubectl exec podname -- 命令
[root@k8scloude1 pod]# kubectl exec nginx -- 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

进入容器执行命令

#进入容器：kubectl exec -it podname -- bash
[root@k8scloude1 pod]# kubectl exec -it nginx -- bash
root@nginx:/# which nginx
/usr/sbin/nginx
root@nginx:/# exit
exit

从物理机复制文件到pod里

[root@k8scloude1 pod]# kubectl cp /etc/hosts nginx:/tmp

[root@k8scloude1 pod]# kubectl exec nginx -- ls /tmp
hosts

从pod里复制文件到物理机

[root@k8scloude1 pod]# kubectl cp nginx:/etc/hosts nginx_hosts
tar: Removing leading `/' from member names

[root@k8scloude1 pod]# ls
nginx_hosts  nginx.yaml  pod1.yaml  pod2.yaml

[root@k8scloude1 pod]# cat nginx_hosts 
# Kubernetes-managed hosts file.
127.0.0.1	localhost
::1	localhost ip6-localhost ip6-loopback
fe00::0	ip6-localnet
fe00::0	ip6-mcastprefix
fe00::1	ip6-allnodes
fe00::2	ip6-allrouters
10.244.251.202	nginx

[root@k8scloude1 pod]# rm -rf nginx_hosts 

查看pod的日志

[root@k8scloude1 pod]# kubectl logs nginx 
/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
2022/01/12 13:41:43 [notice] 1#1: using the "epoll" event method
2022/01/12 13:41:43 [notice] 1#1: nginx/1.21.5
2022/01/12 13:41:43 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6) 
2022/01/12 13:41:43 [notice] 1#1: OS: Linux 3.10.0-693.el7.x86_64
2022/01/12 13:41:43 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2022/01/12 13:41:43 [notice] 1#1: start worker processes
2022/01/12 13:41:43 [notice] 1#1: start worker process 31
2022/01/12 13:41:43 [notice] 1#1: start worker process 32

当一个pod里有两个容器，怎么查看？kubectl exec -it podname -c 容器名 -- 命令

首先创建一个包含2个容器的pod

[root@k8scloude1 pod]# vim pod2.yaml 

[root@k8scloude1 pod]# cat pod2.yaml 
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod1
  name: pod1
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: n1
    resources: {}
  - image: nginx
    imagePullPolicy: IfNotPresent
    command: ["sh","-c","sleep 10"]
    name: n2
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

[root@k8scloude1 pod]# kubectl apply -f pod2.yaml 
pod/pod1 created

[root@k8scloude1 pod]# kubectl get pod 
NAME    READY   STATUS    RESTARTS   AGE
pod1    2/2     Running   0          6s

查看pod1的描述信息

[root@k8scloude1 pod]# kubectl describe pod pod1 
Name:         pod1
Namespace:    pod
Priority:     0
Node:         k8scloude2/192.168.110.129
Start Time:   Wed, 12 Jan 2022 21:53:05 +0800
Labels:       run=pod1
Annotations:  cni.projectcalico.org/containerID: d103a6cb8e6535c5cfa8cf52153a80c11b75c0b7a744c7ad1028f3f4e88a627e
              cni.projectcalico.org/podIP: 10.244.112.141/32
              cni.projectcalico.org/podIPs: 10.244.112.141/32
Status:       Running
IP:           10.244.112.141
IPs:
  IP:  10.244.112.141
Containers:
  n1:
    Container ID:   docker://e54540c02e54109af7437fd00f18bcca3969e75eafb336dadb9ddb21022520ed
    Image:          nginx
    Image ID:       docker-pullable://nginx@sha256:0d17b565c37bcbd895e9d92315a05c1c3c9a29f762b011a10c54a66cd53c9b31
    Port:           <none>
    Host Port:      <none>
    State:          Running
      Started:      Wed, 12 Jan 2022 21:53:06 +0800
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-42h2q (ro)
  n2:
    Container ID:  docker://2d09c058d4c11f51c1c22c58012c79f5b8ec8327fcdd43e17f4533cb01f098d0
    Image:         nginx
    Image ID:      docker-pullable://nginx@sha256:0d17b565c37bcbd895e9d92315a05c1c3c9a29f762b011a10c54a66cd53c9b31
    Port:          <none>
    Host Port:     <none>
    Command:
      sh
      -c
      sleep 10
    State:          Terminated
      Reason:       Completed
      Exit Code:    0
      Started:      Wed, 12 Jan 2022 21:53:39 +0800
      Finished:     Wed, 12 Jan 2022 21:53:49 +0800
    Last State:     Terminated
      Reason:       Completed
      Exit Code:    0
      Started:      Wed, 12 Jan 2022 21:53:17 +0800
      Finished:     Wed, 12 Jan 2022 21:53:27 +0800
    Ready:          False
    Restart Count:  2
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-42h2q (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             False 
  ContainersReady   False 
  PodScheduled      True 
Volumes:
  kube-api-access-42h2q:
    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  46s                default-scheduler  Successfully assigned pod/pod1 to k8scloude2
  Normal   Pulled     46s                kubelet            Container image "nginx" already present on machine
  Normal   Created    46s                kubelet            Created container n1
  Normal   Started    46s                kubelet            Started container n1
  Normal   Pulled     13s (x3 over 46s)  kubelet            Container image "nginx" already present on machine
  Normal   Created    13s (x3 over 46s)  kubelet            Created container n2
  Normal   Started    13s (x3 over 46s)  kubelet            Started container n2
  Warning  BackOff    3s (x2 over 24s)   kubelet            Back-off restarting failed container

查看pod里的n1容器的/tmp目录

#当一个pod里有两个容器，怎么查看：kubectl exec -it podname -c 容器名 -- 命令
[root@k8scloude1 pod]# kubectl exec -it pod1 -c n1 -- ls /tmp

查看pod里的n2容器的/tmp目录

[root@k8scloude1 pod]# kubectl exec -it pod1 -c n2 -- ls /tmp

进入pod1里的n1容器

[root@k8scloude1 pod]# kubectl exec -it pod1 -c n1 -- bash
root@pod1:/# which nginx
/usr/sbin/nginx
root@pod1:/# exit
exit

查看pod1里的n1容器日志

[root@k8scloude1 pod]# kubectl logs pod1 -c n1
/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
2022/01/12 13:53:06 [notice] 1#1: using the "epoll" event method
2022/01/12 13:53:06 [notice] 1#1: nginx/1.21.5
2022/01/12 13:53:06 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6) 
2022/01/12 13:53:06 [notice] 1#1: OS: Linux 3.10.0-693.el7.x86_64
2022/01/12 13:53:06 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2022/01/12 13:53:06 [notice] 1#1: start worker processes
2022/01/12 13:53:06 [notice] 1#1: start worker process 32
2022/01/12 13:53:06 [notice] 1#1: start worker process 33

编辑pod: kubectl edit pod podname

[root@k8scloude1 pod]# kubectl edit pod nginx 
Edit cancelled, no changes made.

容器里运行命令的一种写法是使用command

[root@k8scloude1 pod]# vim pod2.yaml 

[root@k8scloude1 pod]# cat pod2.yaml 
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: pod1
  name: pod1
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: n1
    resources: {}
  - image: nginx
    imagePullPolicy: IfNotPresent
    command: ["sh","-c","sleep 10"]
    name: n2
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

容器里运行命令的另一种写法是使用args

[root@k8scloude1 pod]# kubectl run podtest --image=nginx --dry-run=client -o yaml -- sh -c sleep 100
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: podtest
  name: podtest
spec:
  containers:
  - args:
    - sh
    - -c
    - sleep
    - "100"
    image: nginx
    name: podtest
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}