来自AI助手的总结
使用CronJob定期执行kubectl重启K8s服务，示例重启MySQL应用
一、使用CronJob定期重启K8s服务
1.1 环境准备
1、创建一个 MySQL 的 PVC
# 定义PVC
[root@k8s-master01 ~]# vim mysql-pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: mysql-data
spec:
accessModes:
- ReadWriteMany
resources:
requests:
storage: 10Gi
storageClassName: nfs-csi
# 创建PVC
[root@k8s-master01 ~]# kaf mysql-pvc.yaml
# 验证
[root@k8s-master01 ~]# kg pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
mysql-data Bound pvc-1c159b41-7afd-467f-a8b9-ecfdf9089ef5 10Gi RWX nfs-csi <unset> 2s
2、创建一个 MySQL 的 Deployment
[root@k8s-master01 ~]# vim deployment-mysql.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: mysql
name: mysql
spec:
replicas: 1
selector:
matchLabels:
app: mysql
strategy:
type: Recreate # 单实例策略，适合有状态应用
template:
metadata:
labels:
app: mysql # 必须与selector.matchLabels一致
spec:
containers:
- name: mysql
image: registry.cn-hangzhou.aliyuncs.com/abroad_images/mysql:8.0.20
ports:
- containerPort: 3306 # 暴露MySQL默认端口
protocol: TCP
env:
- name: MYSQL_ROOT_PASSWORD # 建议生产环境改用Secret
value: "123456" # 示例密码，实际需加密
volumeMounts:
- name: data
mountPath: /var/lib/mysql # MySQL数据持久化目录
livenessProbe: # 存活探针
tcpSocket:
port: 3306
initialDelaySeconds: 30 # 容器启动30秒后开始探测
timeoutSeconds: 3 # 探测超时时间
periodSeconds: 30 # 每30秒探测一次
successThreshold: 1
failureThreshold: 2 # 连续失败2次标记为不健康
readinessProbe: # 就绪探针（配置同存活探针）
tcpSocket:
port: 3306
initialDelaySeconds: 30
timeoutSeconds: 3
periodSeconds: 30
successThreshold: 1
failureThreshold: 2
volumes: # 卷定义（与containers同级）
- name: data
persistentVolumeClaim:
claimName: mysql-data # 关联的PVC名称
dnsPolicy: ClusterFirst # DNS解析策略（默认值）
3、创建MySQL,并查看启动状态
[root@k8s-master01 ~]# kaf deployment-mysql.yaml
# 验证
[root@k8s-master01 ~]# kgp
NAME READY STATUS RESTARTS AGE
mysql-676759b6c-g9jj7 1/1 Running 0 53s
1.1 定期重启K8s服务
有时候需要定期重启 K8s 中的服务，也可以使用 CronJob 实现。
如果一个时间点需要重启多个服务，则把命令写入多行即可
...
...
spec:
containers:
- command:
- /bin/bash
- -c
- kubectl rollout restart deployment mysql -n default
- kubectl rollout restart deployment a -n default
- kubectl rollout restart deployment b -n default
- kubectl rollout restart deployment xxx -n default
...
...
如果不同时间点需要重启多个服务，则拆分多个cronjob即可
# 每周六凌晨两点重启下default命名空间下的mysql应用
kubectl create cronjob restart \
--image=registry.cn-hangzhou.aliyuncs.com/abroad_images/kubectl:latest \
--schedule="01 18 * * 5" \
--dry-run=client -o yaml \
-- /bin/bash -c "kubectl rollout restart deployment mysql -n default" \
> restart-cronjob.yaml
# 每周日凌晨两点重启下default命名空间下的a应用和b应用
kubectl create cronjob restart \
--image=registry.cn-hangzhou.aliyuncs.com/abroad_images/kubectl:latest \
--schedule="01 18 * * 6" \
--dry-run=client -o yaml \
-- /bin/bash -c "kubectl rollout restart deployment a -n default"
-- /bin/bash -c "kubectl rollout restart deployment b -n default"
\
> restart-cronjob.yaml
# 每周五凌晨两点重启下default命名空间下的b应用
kubectl create cronjob restart \
--image=registry.cn-hangzhou.aliyuncs.com/abroad_images/kubectl:latest \
--schedule="01 18 * * 4" \
--dry-run=client -o yaml \
-- /bin/bash -c "kubectl rollout restart deployment b -n default" \
> restart-cronjob.yaml
下面进行示例演示：每周六凌晨两点重启default命名空间的mysql应用
1、创建一个命名空间
k create ns cronjob
2、创建重启 K8s 服务的权限
# 创建ClusterRole
k create clusterrole deployment-restart --verb=get,update,patch --resource=deployments.apps
# 创建ClusterRolebinding
kubectl create clusterrolebinding deployment-restart-binding \
--clusterrole=deployment-restart \
--serviceaccount=cronjob:default
3、创建cronjob
输出cronjob模板文件，每周六凌晨两点重启下default命名空间下的mysql应用
kubectl create cronjob restart \
--image=registry.cn-hangzhou.aliyuncs.com/abroad_images/kubectl:latest \
--schedule="01 18 * * 5" \
--dry-run=client -o yaml \
-- /bin/bash -c "kubectl rollout restart deployment mysql -n default" \
> restart-cronjob.yaml
重新定义cronjob文件，每周六凌晨两点重启下default命名空间下的mysql应用
[root@k8s-master01 ~]# vim restart-cronjob.yaml
apiVersion: batch/v1
kind: CronJob
metadata:
name: restart
namespace: cronjob
spec:
concurrencyPolicy: Allow
suspend: false
schedule: 01 18 * * 5
successfulJobsHistoryLimit: 3
failedJobsHistoryLimit: 3
jobTemplate:
metadata:
name: restart
spec:
template:
metadata:
spec:
containers:
- command:
- /bin/bash
- -c
- kubectl rollout restart deployment mysql -n default
image: registry.cn-hangzhou.aliyuncs.com/abroad_images/kubectl:latest
name: restart
resources: {}
restartPolicy: Never
创建crontab
[root@k8s-master01 ~]# kaf restart-cronjob.yaml
# 验证
[root@k8s-master01 ~]# kg cj -n cronjob
NAME SCHEDULE TIMEZONE SUSPEND ACTIVE LAST SCHEDULE AGE
restart 01 18 * * * <none> False 0 <none> 2s
4、手动触发crontab
# 触发前查看deploy的age时间，观察到为10分钟
[root@k8s-master01 ~]# kg deploy
NAME READY UP-TO-DATE AVAILABLE AGE
mysql 1/1 1 1 10m
# 手动触发
[root@k8s-master01 ~]# k create job restart-deploy-test --from=cronjob.batch/restart -n cronjob
5、验证
# 查看job
[root@k8s-master01 ~]# kg job -n cronjob
[root@k8s-master01 ~]# kg job -n cronjob
NAME STATUS COMPLETIONS DURATION AGE
restart-deploy-test Complete 1/1 31s 3m24s
# 查看pod
[root@k8s-master01 ~]# kgp -n cronjob
NAME READY STATUS RESTARTS AGE
restart-deploy-test-c9t96 0/1 Completed 0 85s
# 查看执行记录
[root@k8s-master01 ~]# k logs -f restart-deploy-test-c9t96 -n cronjob
deployment.apps/mysql restarted
# 查看default命名空间的pod,已重启
[root@k8s-master01 ~]# kgp
NAME READY STATUS RESTARTS AGE
mysql-6ccd44dffc-vvbk4 1/1 Running 0 84s
6、环境复原
k delete -f restart-cronjob.yaml -f deployment-mysql.yaml -f mysql-pvc.yaml
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