kubectl管理kubernetes集群

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[root@master ~]# kubectl get nodes 查看集群节点
NAME STATUS AGE
node1 Ready 25m
node2 Ready 19m
[root@master ~]# kubectl version 查看版本
Client Version: version.Info{Major:”1″, Minor:”5″, GitVersion:”v1.5.2″, GitCommit:”269f928217957e7126dc87e6adfa82242bfe5b1e”, GitTreeState:”clean”, BuildDate:”2017-07-03T15:31:10Z”, GoVersion:”go1.7.4″, Compiler:”gc”, Platform:”linux/amd64″}
Server Version: version.Info{Major:”1″, Minor:”5″, GitVersion:”v1.5.2″, GitCommit:”269f928217957e7126dc87e6adfa82242bfe5b1e”, GitTreeState:”clean”, BuildDate:”2017-07-03T15:31:10Z”, GoVersion:”go1.7.4″, Compiler:”gc”, Platform:”linux/amd64″}
[root@master ~]# kubectl run nginx –image=docker.io/nginx –replicas=1 –port=9000
deployment “nginx” created
[root@master ~]# kubectl get deployment
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
nginx 1 1 1 0 15s
[root@master ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-2187705812-8r0h4 1/1 Running 0 1h
[root@master ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
nginx-2187705812-8r0h4 1/1 Running 0 1h 10.255.4.2 node1
想要删除一个容器的时候：

[root@master ~]# kubectl delete pod nginx-2187705812-8r0h4
pod “nginx-2187705812-8r0h4” deleted
[root@master ~]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-2187705812-6dn2r 0/1 ContainerCreating 0 4s
删除了之后还依然有，这个是因为创建 deployment 的时候参数 –replicas= 1 起作用了。想要删除的话直接删除 deployment 就可以了。

[root@master ~]# kubectl delete deployment nginx
deployment “nginx” deleted

yaml 语法：

[root@master ~]# kubectl create -f MySQL-deployment.yaml
deployment “mysql” created
[root@master ~]# kubectl get deployment
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
mysql 1 1 1 1 9s
[root@master ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
mysql-2261771434-r8td1 1/1 Running 0 16s 10.255.4.2 node1
在 node1 上查看 mysql docker 实例

[root@node1 ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e33797549b8e docker.io/mysql/mysql-server “/entrypoint.sh my…” 4 minutes ago Up 4 minutes (healthy) k8s_mysql.31ec27ee_mysql-2261771434-r8td1_default_351da1d4-f082-11e8-bbf2-000c297d60e3_089418b7

kubectl 其他参数：

logs 取得 pod 中容器的 log 信息

exec 在容器中执行一条命令

cp 从容器拷出或者想容器中拷入文件

attach attach 到一个运行的容器上

logs

[root@master ~]# kubectl get pod
NAME READY STATUS RESTARTS AGE
mysql-2261771434-r8td1 1/1 Running 0 18m
[root@master ~]# kubectl logs mysql-2261771434-r8td1
[Entrypoint] MySQL Docker Image 5.7.20-1.1.2
[Entrypoint] Initializing database
[Entrypoint] Database initialized
Warning: Unable to load ‘/usr/share/zoneinfo/iso3166.tab’ as time zone. Skipping it.
Warning: Unable to load ‘/usr/share/zoneinfo/zone.tab’ as time zone. Skipping it.
Warning: Unable to load ‘/usr/share/zoneinfo/zone1970.tab’ as time zone. Skipping it.
[Entrypoint] ignoring /docker-entrypoint-initdb.d/*
[Entrypoint] Server shut down
[Entrypoint] MySQL init process done. Ready for start up.
[Entrypoint] Starting MySQL 5.7.20-1.1.2

exec：
[root@master ~]# kubectl exec mysql-2261771434-r8td1 ls
[root@master ~]# kubectl exec -it mysql-2261771434-r8td1 bash
bash-4.2#
cp：
[root@master ~]# kubectl cp mysql-2261771434-r8td1:/tmp/hosts /etc/hosts
error: unexpected EOF

[root@master ~]# kubectl cp –help
Examples:
# !!!Important Note!!!
# Requires that the ‘tar’ binary is present in your container 使用 kubectl cp 你的容器实例中必须有 tar 命令，如果没有的话就会失败
# image. If ‘tar’ is not present, ‘kubectl cp’ will fail.
[root@master ~]# kubectl exec -it mysql-2261771434-r8td1 bash
bash-4.2# yum install tar net-tools -y

bash-4.2# echo ‘this is test’ > /tmp/test.txt

再次测试：

拷贝出来

[root@master ~]# kubectl cp mysql-2261771434-r8td1:/tmp/test.txt /opt/test.txt
[root@master ~]# more /opt/test.txt
this is test

拷贝回去：

[root@master ~]# echo “this is out” >> /opt/test.txt

[root@master ~]# kubectl cp /opt/test.txt mysql-2261771434-r8td1:/tmp/test.txt

[root@master ~]# kubectl exec -it mysql-2261771434-r8td1 bash
bash-4.2# cat /tmp/test.txt
this is test

this is out

kubectl attach：

用户取得 pod 中容器的实时信息，可以持续不断实时的取出信息。类似于 tail -f

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