Kubectl
一、下载kubectl
kubectl github下载地址：https://github.com/kubernetes/kubectl/releases
二、创建配置文件夹
Linux
mkdir ~/.kube
Windows CMD
mkdir %USERPROFILE%\.kube
# %USERPROFILE% 当前用户目录
三、创建编辑kubectl配置文件
apiVersion: v1
# 集群信息
clusters:
- cluster:
certificate-authority-data: **CA证书***
server: https://开发k8s环境APIServer的IP地址:6443
name: k8s-dev
- cluster:
certificate-authority-data: **CA证书***
server: https://测试k8s环境APIServer的IP地址:8443
name: k8s-test
- cluster:
certificate-authority-data: **CA证书***
server: https://UAT k8s环境APIServer的IP地址:8443
name: k8s-uat
- cluster:
certificate-authority-data: **CA证书***
server: https://生产k8s环境APIServer的IP地址:8443
name: k8s-pro
# 集群上下文环境
contexts:
- context:
cluster: k8s-dev
user: k8s-dev-admin
name: k8s-dev
- context:
cluster: k8s-test
user: k8s-test-admin
name: k8s-test
- context:
cluster: k8s-uat
user: k8s-uat-admin
name: k8s-uat
- context:
cluster: k8s-pro
user: k8s-pro-readonly
name: k8s-pro
# 当前使用的上下文环境
current-context: k8s-dev
kind: Config
preferences: {}
#集群用户信息及证书信息
users:
- name: k8s-dev
user:
client-certificate-data: **用户证书**
client-key-data： **用户私钥**
- name: k8s-test
user:
client-certificate-data: **用户证书**
client-key-data： **用户私钥**
- name: k8s-uat
user:
client-certificate-data: **用户证书**
client-key-data： **用户私钥**
- name: k8s-pro
user:
client-certificate-data: **用户证书**
client-key-data： **用户私钥**
四、切换Kubernetes集群上下文
#切换至开发k8s环境上下文
kubectl config use-context k8s-dev
#切换至开发k8s环境上下文
kubectl config use-context k8s-test
#切换至开发k8s环境上下文
kubectl config use-context k8s-uat
#切换至开发k8s环境上下文
kubectl config use-context k8s-pro
五、kubectl命令快捷操作
1、设置别名快速使用kubectl命令
Windows
doskey k=kubectl $*
# $*表示这个命令还可能有其他参数
Linux
alias k='kubectl'
2、设置别名快速切换集群上下文
Windows
doskey k2d=kubectl config use-context k8s-dev
doskey k2t=kubectl config use-context k8s-test
doskey k2u=kubectl config use-context k8s-uat
doskey k2p=kubectl config use-context k8s-pro
Linux
alias k2d='kubectl config use-context k8s-dev'
alias k2t='kubectl config use-context k8s-test'
alias k2u='kubectl config use-context k8s-uat'
alias k2p='kubectl config use-context k8s-pro'
3、设置别名永久生效
Windows
①创建bat脚本cmdalias.cmd
@doskey k=kubectl $* @doskey k2d=kubectl config use-context k8s-dev @doskey k2t=kubectl config use-context k8s-test @doskey k2u=kubectl config use-context k8s-uat @doskey k2p=kubectl config use-context k8s-pro # @表示执行这条命令时不显示这条命令本身②修改注册表
方式1：手动在注册HKEY_CURRENT_USER\Software\Microsoft\Command Processor下添加一项AutoRun，把值设为bat脚本的路径方式2：创建编写一个注册表修改文件，名为：add-regkey.reg，双击行这个文件,导入注册表添加的值Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\Software\Microsoft\Command Processor] "AutoRun"="%USERPROFILE%\\.kube\\cmdalias.cmd"
Linux
echo "alias k='kubectl'" >> /etc/profile && \
echo "alias k2d='kubectl config use-context k8s-dev'" >> /etc/profile && \
echo "alias k2t='kubectl config use-context k8s-test'" >> /etc/profile && \
echo "alias k2u='kubectl config use-context k8s-uat'" >> /etc/profile && \
echo "alias k2p='kubectl config use-context k8s-pro'" >> /etc/profile && \
source /etc/profile
六、Kubectl Config命令详解
1. If the --kubeconfig flag is set, then only that file is loaded. The flag may only be set once and no merging takes
place.
2. If $KUBECONFIG environment variable is set, then it is used a list of paths (normal path delimitting rules for your
system). These paths are merged. When a value is modified, it is modified in the file that defines the stanza. When a
value is created, it is created in the first file that exists. If no files in the chain exist, then it creates the last
file in the list.
3. Otherwise, ${HOME}/.kube/config is used and no merging takes place.
Usage:
kubectl config SUBCOMMAND [options]
Available Commands:
current-context Displays the current-context
delete-cluster Delete the specified cluster from the kubeconfig
delete-context Delete the specified context from the kubeconfig
get-clusters Display clusters defined in the kubeconfig
get-contexts Describe one or many contexts
rename-context Renames a context from the kubeconfig file.
set Sets an individual value in a kubeconfig file
set-cluster Sets a cluster entry in kubeconfig
set-context Sets a context entry in kubeconfig
set-credentials Sets a user entry in kubeconfig
unset Unsets an individual value in a kubeconfig file
use-context Sets the current-context in a kubeconfig file
view Display merged kubeconfig settings or a specified kubeconfig file
七、Kubectl常用操作
1、节点维护
# 1. 设置节点不可被调度
kubectl cordon 节点名
# 2. 驱逐节点上的POD
kubectl drain 节点名 --delete-local-data --ignore-daemonsets --force
# --delete-local-data 即使pod使用了emptyDir也删除
# --ignore-daemonsets 忽略deamonset控制器的pod，如果不忽略，deamonset控制器控制的pod被删除后可能马上又在此节点上启动起来,会成为死循环；
# --force 不加force参数只会删除该NODE上由ReplicationController, ReplicaSet, DaemonSet,StatefulSet or Job创建的Pod，加了后还会删除'裸奔的pod'(没有绑定到任何replication controller)
# 3. 下掉节点
kubectl delete node stg-k8s-node1
# 4. 修复操作
# 5. 设置节点可被调度
kubectl uncordon 节点名
2、Deployment历史版本管理
# 查看版本历史版本
kubectl rollout history deployment test
# 查看指定历史版本的详细信息
kubectl rollout history deployment test --revision=1
# 回滚到上一个版本
kubectl rollout undo deployment/test
# 回滚到指定版本
kubectl rollout undo deployment/test --to-revision=2
# 查看Deployment的发布状态
kubectl rollout status deploy/test
3、直接修改资源对象参数
kubectl set image deployment/test nginx=nginx:1.15
# 直接更新所有容器镜像
kubectl set image daemonset abc *=nginx:1.9.1
4、运行测试容器
# 创建POD
kubectl run nginx --image=nginx --port=80 --labels="app=nginx"
kubectl expose pod nginx --name=nginx --port=80 --target-port=80 --protocol=TCP
# 创建Deployment
kubectl create deployment nginx --image=nginx --port=80 --replicas=1
kubectl expose deployment nginx --port=80 --target-port=80
5、等待验证k8s资源pod部署状态
kubectl apply -f k8s-job-application.yaml
kubectl -n $NAMESPACE wait --for=condition=complete --timeout=50s job/$CI_PROJECT_NAME || exit_code=$? | \
if [ $exit_code -ne 0 ];then
ROLLBACK_ID=$(kubectl -n $NAMESPACE rollout undo deployment/$CI_PROJECT_NAME -ojson | jq -r '.status.observedGeneration') ;
curl -s https://oapi.dingtalk.com/robot/send?access_token="$PIPELINE_DINGDING_ROBOT_TOKEN" -H 'Content-Type: application/json' -d '{"msgtype": "markdown","markdown": {"title": "Gitlab流水线部署失败","text": "['$CI_PROJECT_NAME-cronjob']('$CI_PROJECT_URL'/-/tree/'$CI_BUILD_REF_NAME')的'$APPENV'环境第['$CI_PIPELINE_ID']('$CI_PIPELINE_URL')号流水线'$CI_JOB_STAGE'阶段失败，已回滚至最近一个稳定版本'$ROLLBACK_ID'，请检查相关错误！"},"at": {"isAtAll": true}}' > /dev/null;
kubectl -n $NAMESPACE logs -l job=$CI_PROJECT_NAME ;
kubectl -n $NAMESPACE delete job $CI_PROJECT_NAME ;
exit 1;
fi
6、kubectl apply从标准输入中读取资源文件
cat <<EOF | kubectl apply -f -
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: nginx
namespace: kube-public
spec:
rules:
- host: "nginx.test.com"
http:
paths:
- path: /
pathType: Prefix
backend:
service:
name: nginx
port:
name: web
EOF
7、kubectl patch更新k8s资源
Kubectl patch 支持以下 3 种 patch 类型：
strategic patch(默认)：根据不同字段 patchStrategy 决定具体的合并 patch 策略。 Strategic merge patch 并非通用的 RFC 标准，而是 Kubernetes 特有的一种更新 Kubernetes 资源对象的方式。与 JSON merge patch 和 JSON patch 相比，strategic merge patch 更为强大。
例如：给deployment添加configmap类型的 Volume 声明与挂载
kubectl patch deployment nginx \ -p '{"spec":{"template":{"spec":{"volumes":[{"name":"nginx-stubstatus-config","configMap":{"name":"nginx-stubstatus-config"}}],"containers":[{"name":"nginx","volumeMounts":[{"name":"nginx-stubstatus-config","mountPath":"/etc/nginx/conf.d"}]}]}}}}'json merge patch：遵循 JSON Merge Patch, RFC 7386[1] 规范，根据 patch 中提供的期望更改的字段及其对应的值，更新到目标中。
json patch：遵循 JSON Patch, RFC 6902[2] 规范，通过明确的指令表示具体的操作。
例如：给Service暴露的端口添加名字
kubectl patch service nginx-exporter -n kube-public \ --type='json' \ -p='[{"op": "add", "path": "/spec/ports/0/name", "value": "application-metrics-exporter"}]'