K8s核心概念 Controller
- Kubernetes核心概念 Controller
- 一、pod控制器controller
- 1.1 Controller作用及分类
- 1.2 Deployment
- 1.2.1 Replicaset控制器的功能
- 1.2.2 Deployment控制器的功能
- 1.2.3 Deployment用于部署无状态应用
- 1.2.4 创建deployment类型应用
- 1.2.5 访问deployment
- 1.2.6 删除deployment中的pod
- 1.2.7 pod版本升级
- 1.2.8 pod版本回退
- 1.2.9 副本扩容
- 1.2.10 副本裁减
- 1.2.11 多副本滚动更新
- 1.2.12 删除deployment
- 1.3 Replicaset
- 二、pod控制器Controller进阶
- 2.1 DaemonSet
- 2.1.1 DaemonSet介绍
- 2.1.2 DaemonSet应用案例
- 2.2 Job
- 2.2.1 Job介绍
- 2.2.2 Job应用案例
- 2.3 CronJob
- 2.3.1 CronJob介绍
- 2.3.2 CronJob应用案例
Kubernetes核心概念 Controller
一、pod控制器controller
1.1 Controller作用及分类
controller用于控制pod
参考: https://kubernetes.io/zh/docs/concepts/workloads/controllers/
控制器主要分为:
- Deployments 部署无状态应用，控制pod升级，回退
- ReplicaSet 副本集，控制pod扩容，裁减
- ReplicationController(相当于ReplicaSet的老版本,现在建议使用Deployments加ReplicaSet替代RC)
- StatefulSets 部署有状态应用，结合Service、存储等实现对有状态应用部署
- DaemonSet 守护进程集，运行在所有集群节点(包括master)，比如使用filebeat，node_exporter
- Jobs 一次性
- Cronjob 周期性
1.2 Deployment
1.2.1 Replicaset控制器的功能
- 支持新的基于集合的selector(以前的rc里没有这种功能)
- 通过改变Pod副本数量实现Pod的扩容和缩容
1.2.2 Deployment控制器的功能
- Deployment集成了上线部署、滚动升级、创建副本、回滚等功能
- Deployment里包含并使用了ReplicaSet
1.2.3 Deployment用于部署无状态应用
无状态应用的特点:
- 所有pod无差别
- 所有pod中容器运行同一个image
- 所有pod可以运行在集群中任意node上
- 所有pod无启动顺序先后之分
- 随意pod数量扩容或缩容
- 例如简单运行一个静态web程序
1.2.4 创建deployment类型应用
- 准备YAML文件
[root@k8s-master1 ~]# vim deployment-nginx.yml
apiVersion: apps/v1
kind: Deployment
metadata:
name: deploy-nginx # deployment名
spec:
replicas: 1 # 副本集,deployment里使用了replicaset
selector:
matchLabels:
app: nginx # 匹配的pod标签,表示deployment和rs控制器控制带有此标签的pod
template: # 代表pod的配置模板
metadata:
labels:
app: nginx # pod的标签
spec:
containers: # 以下为pod里的容器定义
- name: nginx
image: nginx:1.15-alpine
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
- 应用YAML文件创建deployment
[root@k8s-master1 ~]# kubectl apply -f deployment-nginx.yml
deployment.apps/deploy-nginx created
- 查看验证
[root@k8s-master1 ~]# kubectl get deployment # deployment可简写成depoly
NAME READY UP-TO-DATE AVAILABLE AGE
deploy-nginx 1/1 1 1 19s
[root@k8s-master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
deploy-nginx-6c9764bb69-pbc2h 1/1 Running 0 75s
[root@k8s-master1 ~]# kubectl get replicasets # replicasets可简写成rs
NAME DESIRED CURRENT READY AGE
deploy-nginx-6c9764bb69 1 1 1 2m6s
1.2.5 访问deployment
- 查看pod的IP地址
[root@k8s-master1 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
deploy-nginx-6d9d558bb6-88nr8 1/1 Running 0 39s 10.244.159.100 k8s-master1 <none> <none>
- 查看所有集群节点的网卡
[root@k8s-master1 ~]# ifconfig tunl0 |head -2
tunl0: flags=193<UP,RUNNING,NOARP> mtu 1480
inet 10.244.159.128 netmask 255.255.255.255
[root@k8s-master2 ~]# ifconfig tunl0 |head -2
tunl0: flags=193<UP,RUNNING,NOARP> mtu 1480
inet 10.244.224.0 netmask 255.255.255.255
[root@k8s-master3 ~]# ifconfig tunl0 |head -2
tunl0: flags=193<UP,RUNNING,NOARP> mtu 1480
inet 10.244.135.192 netmask 255.255.255.255
[root@k8s-worker1 ~]# ifconfig tunl0 |head -2
tunl0: flags=193<UP,RUNNING,NOARP> mtu 1480
inet 10.244.194.64 netmask 255.255.255.255
- 可以看到所有集群节点的IP都为
10.244.0.0/16这个大网段内的子网
- 在任意集群节点上都可以访问此deploy里pod
# curl 10.244.159.100
结果是任意集群节点都可以访问这个POD,但集群外部是不能访问的
1.2.6 删除deployment中的pod
- 删除pod（注意: 是删除deployment中的pod）
[root@k8s-master1 ~]# kubectl delete pod deploy-nginx-6c9764bb69-pbc2h
pod "deploy-nginx-6c9764bb69-pbc2h" deleted
- 再次查看，发现又重新启动了一个pod(节点由k8s-master1转为k8s-worker1 了，IP地址也变化了)
[root@k8s-master1 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
deploy-nginx-6d9d558bb6-f2t6r 1/1 Running 0 28s 10.244.194.94 k8s-worker1 <none> <none>
也就是说**pod的IP不是固定的，比如把整个集群关闭再启动，pod也会自动启动，但是IP地址也会变化**
既然IP地址不是固定的，所以需要一个固定的访问endpoint给用户，那么这种方式就是service.
1.2.7 pod版本升级
查看帮助
[root@k8s-master1 ~]# kubectl set image -h
- 升级前验证nginx版本
[root@k8s-master1 ~]# kubectl describe pods deploy-nginx-6d9d558bb6-f2t6r | grep Image:
Image: nginx:1.15-alpine
[root@k8s-master1 ~]# kubectl exec deploy-nginx-6d9d558bb6-f2t6r -- nginx -v
nginx version: nginx/1.15.12
- 升级为1.16版
[root@k8s-master1 ~]# kubectl set image deployment deploy-nginx nginx=nginx:1.16-alpine --record
deployment.apps/deploy-nginx image updated
说明:
-
deployment deploy-nginx代表名为deploy-nginx的deployment -
nginx=nginx:1.16-alpine前面的nginx为容器名 -
–record 表示会记录
容器名怎么查看?
-
kubectl describe pod pod名查看 -
kubectl edit deployment deployment名来查看容器名 -
kubectl get deployment deployment名 -o yaml来查看容器名
- 验证
如果升级的pod数量较多，则需要一定时间，可通过下面命令查看是否已经成功
[root@k8s-master1 ~]# kubectl rollout status deployment deploy-nginx
deployment "deploy-nginx" successfully rolled out
验证 pod
[root@k8s-master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
deploy-nginx-5f4749c8c8-nskp9 1/1 Running 0 104s 更新后,后面的id变了
验证版本
[root@k8s-master1 ~]# kubectl describe pod deploy-nginx-5f4749c8c8-nskp9 |grep Image:
Image: nginx:1.16-alpine 升级为1.16了
[root@k8s-master1 ~]# kubectl exec deploy-nginx-5f4749c8c8-nskp9 -- nginx -v
nginx version: nginx/1.16.1 升级为1.16了
练习: 再将nginx1升级为1.17版
[root@k8s-master1 ~]# kubectl set image deployment deploy-nginx nginx=nginx:1.17-alpine --record
deployment.apps/deploy-nginx image updated
1.2.8 pod版本回退
- 查看版本历史信息
[root@k8s-master1 ~]# kubectl rollout history deployment deploy-nginx
deployment.apps/deploy-nginx
REVISION CHANGE-CAUSE
1 <none> 原1.15版
2 kubectl set image deployment deploy-nginx nginx=nginx:1.16-alpine --record=true
3 kubectl set image deployment deploy-nginx nginx=nginx:1.17-alpine --record=true
- 定义要回退的版本（还需要执行才是真的回退版本)
[root@k8s-master1 ~]# kubectl rollout history deployment deploy-nginx --revision=1
deployment.apps/deploy-nginx with revision #1
Pod Template:
Labels: app=nginx
pod-template-hash=6c9764bb69
Containers:
nginx:
Image: nginx:1.15-alpine 可以看到这是要回退的1.15版本
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
- 执行回退
[root@k8s-master1 ~]# kubectl rollout undo deployment deploy-nginx --to-revision=1
deployment.apps/deploy-nginx rolled back
- 验证
[root@k8s-master1 ~]# kubectl rollout history deployment deploy-nginx
deployment.apps/deploy-nginx
REVISION CHANGE-CAUSE
2 kubectl set image deployment deploy-nginx nginx=nginx:1.16-alpine --record=true
3 kubectl set image deployment deploy-nginx nginx=nginx:1.17-alpine --record=true
4 <none> 回到了1.15版,但revision的ID变了
[root@k8s-master1 ~]# kubectl describe pod deploy-nginx-6c9764bb69-zgwpj |grep Image:
Image: nginx:1.15-alpine 回到了1.15版
[root@k8s-master1 ~]# kubectl exec deploy-nginx-6c9764bb69-zgwpj -- nginx -v
nginx version: nginx/1.15.12 回到了1.15版
1.2.9 副本扩容
查看帮助
[root@k8s-master1 ~]# kubectl scale -h
[root@k8s-master1 ~]# kubectl scale deployment deploy-nginx --replicas=2
deployment.apps/deploy-nginx scaled
[root@k8s-master1 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
deploy-nginx-6d9d558bb6-4c64l 1/1 Running 0 27s 10.244.159.157 k8s-master1 <none> <none>
deploy-nginx-6d9d558bb6-hkq2b 1/1 Running 0 71s 10.244.194.95 k8s-worker1 <none> <none>
在两个node节点上各1个pod
[root@master ~]# kubectl scale deployment deploy-nginx --replicas=4
#继续扩容(我们这里只有2个node,但是可以大于node节点数据)
deployment.extensions/nginx1 scaled
[root@k8s-master1 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
deploy-nginx-6d9d558bb6-4c64l 1/1 Running 0 87s 10.244.159.157 k8s-master1 <none> <none>
deploy-nginx-6d9d558bb6-586dr 1/1 Running 0 31s 10.244.135.197 k8s-master3 <none> <none>
deploy-nginx-6d9d558bb6-hkq2b 1/1 Running 0 2m11s 10.244.194.95 k8s-worker1 <none> <none>
deploy-nginx-6d9d558bb6-kvgsc 1/1 Running 0 31s 10.244.224.13 k8s-master2 <none> <none>
1.2.10 副本裁减
[root@k8s-master1 ~]# kubectl scale deployment deploy-nginx --replicas=1
deployment.apps/deploy-nginx scaled
[root@k8s-master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
deploy-nginx-6d9d558bb6-hkq2b 1/1 Running 0 2m56s
1.2.11 多副本滚动更新
- 先扩容多点副本
[root@k8s-master1 ~]# kubectl scale deployment deploy-nginx --replicas=16
deployment.apps/deploy-nginx scaled
[root@master ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx1-7d9b8757cf-2hd48 1/1 Running 0 61s
nginx1-7d9b8757cf-5m72n 1/1 Running 0 61s
nginx1-7d9b8757cf-5w2xr 1/1 Running 0 61s
nginx1-7d9b8757cf-5wmdh 1/1 Running 0 61s
nginx1-7d9b8757cf-6szjj 1/1 Running 0 61s
nginx1-7d9b8757cf-9dgsw 1/1 Running 0 61s
nginx1-7d9b8757cf-dc7qj 1/1 Running 0 61s
nginx1-7d9b8757cf-l52pr 1/1 Running 0 61s
nginx1-7d9b8757cf-m7rt4 1/1 Running 0 26m
nginx1-7d9b8757cf-mdkj2 1/1 Running 0 61s
nginx1-7d9b8757cf-s79kp 1/1 Running 0 61s
nginx1-7d9b8757cf-shhvk 1/1 Running 0 61s
nginx1-7d9b8757cf-sv8gb 1/1 Running 0 61s
nginx1-7d9b8757cf-xbhf4 1/1 Running 0 61s
nginx1-7d9b8757cf-zgdgd 1/1 Running 0 61s
nginx1-7d9b8757cf-zzljl 1/1 Running 0 61s
nginx2-559567f789-8hstz 1/1 Running 1 114m
[root@k8s-master1 ~]# kubectl set image deployment deploy-nginx nginx=nginx:1.17-alpine --record
deployment.apps/deploy-nginx image updated
[root@k8s-master1 ~]# kubectl rollout status deployment deploy-nginx
......
Waiting for deployment "deploy-nginx" rollout to finish: 13 of 16 updated replicas are available...
Waiting for deployment "deploy-nginx" rollout to finish: 14 of 16 updated replicas are available...
Waiting for deployment "deploy-nginx" rollout to finish: 15 of 16 updated replicas are available...
deployment "deploy-nginx" successfully rolled out
1.2.12 删除deployment
如果使用 kubectl delete deployment deploy-nginx 命令删除deployment,那么里面的pod也会被自动删除
1.3 Replicaset
- 编写YAML文件
[root@master ~]# vim rs-nginx.yml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
name: rs-nginx
namespace: default
spec: # replicaset的spec
replicas: 2 # 副本数
selector: # 标签选择器,对应pod的标签
matchLabels:
app: nginx # 匹配的label
template:
metadata:
name: nginx # pod名
labels: # 对应上面定义的标签选择器selector里面的内容
app: nginx
spec: # pod的spec
containers:
- name: nginx
image: nginx:1.15-alpine
ports:
- name: http
containerPort: 80
[root@k8s-master1 ~]# kubectl apply -f rs-nginx.yml
replicaset.apps/rs-nginx created
[root@k8s-master1 ~]# kubectl get rs
NAME DESIRED CURRENT READY AGE
rs-nginx 2 2 2 26s
[root@k8s-master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
rs-nginx-7j9hz 1/1 Running 0 44s
rs-nginx-pncsk 1/1 Running 0 43s
[root@k8s-master1 ~]# kubectl get deployment
No resources found.
找不到deployment,说明创建rs并没有创建deployment
二、pod控制器Controller进阶
2.1 DaemonSet
2.1.1 DaemonSet介绍
- DaemonSet能够让所有（或者特定）的节点运行同一个pod。
- 当节点加入到K8S集群中，pod会被（DaemonSet）调度到该节点上运行，当节点从K8S集群中被移除，被DaemonSet调度的pod会被移除
- 如果删除DaemonSet，所有跟这个DaemonSet相关的pods都会被删除。
- 如果一个DaemonSet的Pod被杀死、停止、或者崩溃，那么DaemonSet将会重新创建一个新的副本在这台计算节点上。
- DaemonSet一般应用于日志收集、监控采集、分布式存储守护进程等
2.1.2 DaemonSet应用案例
- 编写YAML文件
[root@master ~]# vim daemonset-nginx.yml
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: daemonset-nginx
spec:
selector:
matchLabels:
name: nginx-ds
template:
metadata:
labels:
name: nginx-ds
spec:
tolerations: # tolerations代表容忍
- key: node-role.kubernetes.io/master # 能容忍的污点key
effect: NoSchedule # kubectl explain pod.spec.tolerations查看(能容忍的污点effect)
containers:
- name: nginx
image: nginx:1.15-alpine
imagePullPolicy: IfNotPresent
resources: # resources资源限制是为了防止master节点的资源被占太多(根据实际情况配置)
limits:
memory: 100Mi
requests:
memory: 100Mi
- apply应用YAML文件
[root@k8s-master1 ~]# kubectl apply -f daemonset-nginx.yml
daemonset.apps/daemonset-nginx created
- 验证
[root@master ~]# kubectl get daemonset # daemonset可简写为ds
[root@k8s-master1 ~]# kubectl get ds
NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE
daemonset-nginx 4 4 4 4 4 <none> 114s
[root@k8s-master1 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
daemonset-nginx-94z6d 1/1 Running 0 6s 10.244.194.104 k8s-worker1 <none> <none>
daemonset-nginx-hs9mk 1/1 Running 0 6s 10.244.135.206 k8s-master3 <none> <none>
daemonset-nginx-jrcf5 1/1 Running 0 6s 10.244.159.167 k8s-master1 <none> <none>
daemonset-nginx-sslpl 1/1 Running 0 6s 10.244.224.22 k8s-master2 <none> <none>
k8s集群中每个节点都会运行一个pod
2.2 Job
2.2.1 Job介绍
- 对于ReplicaSet而言，它希望pod保持预期数目、持久运行下去，除非用户明确删除，否则这些对象一直存在，它们针对的是耐久性任务，如web服务等。
- 对于非耐久性任务，比如压缩文件，任务完成后，pod需要结束运行，不需要pod继续保持在系统中，这个时候就要用到Job。
- Job负责批量处理短暂的一次性任务 (short lived one-off tasks)，即仅执行一次的任务，它保证批处理任务的一个或多个Pod成功结束。
2.2.2 Job应用案例
计算圆周率2000位
- 编写YAML文件
[root@master ~]# vim job1.yml
apiVersion: batch/v1
kind: Job
metadata:
name: pi # job名
spec:
template:
metadata:
name: pi # pod名
spec:
containers:
- name: pi # 容器名
image: perl # 此镜像有800多M,可提前导入到所有节点,也可能指定导入到某一节点然后指定调度到此节点
imagePullPolicy: IfNotPresent
command: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
restartPolicy: Never # 执行完后不再重启
- 应用YAML文件创建job
[root@master ~]# kubectl apply -f job1.yml
job.batch/pi created
[root@k8s-master1 ~]# kubectl get jobs
NAME COMPLETIONS DURATION AGE
pi 1/1 11s 18s
[root@k8s-master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
pi-tjq9b 0/1 Completed 0 27s
Completed状态,也不再是ready状态
[root@k8s-master1 ~]# kubectl logs pi-tjq9b
3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989380952572010654858632788659361533818279682303019520353018529689957736225994138912497217752834791315155748572424541506959508295331168617278558890750983817546374649393192550604009277016711390098488240128583616035637076601047101819429555961989467678374494482553797747268471040475346462080466842590694912933136770289891521047521620569660240580381501935112533824300355876402474964732639141992726042699227967823547816360093417216412199245863150302861829745557067498385054945885869269956909272107975093029553211653449872027559602364806654991198818347977535663698074265425278625518184175746728909777727938000816470600161452491921732172147723501414419735685481613611573525521334757418494684385233239073941433345477624168625189835694855620992192221842725502542568876717904946016534668049886272327917860857843838279679766814541009538837863609506800642251252051173929848960841284886269456042419652850222106611863067442786220391949450471237137869609563643719172874677646575739624138908658326459958133904780275901
创建固定次数job
- 编写YAML文件
[root@master ~]# vim job2.yml
apiVersion: batch/v1
kind: Job
metadata:
name: busybox-job
spec:
completions: 10 # 执行job的次数
parallelism: 1 # 执行job的并发数
template:
metadata:
name: busybox-job-pod
spec:
containers:
- name: busybox
image: busybox
imagePullPolicy: IfNotPresent
command: ["echo", "hello"]
restartPolicy: Never
- 应用YAML文件创建job
[root@k8s-master1 ~]# kubectl apply -f job2.yml
job.batch/busybox-job created
- 验证
[root@k8s-master1 ~]# kubectl get job
NAME COMPLETIONS DURATION AGE
busybox-job 2/10 9s 9s
[root@k8s-master1 ~]# kubectl get job
NAME COMPLETIONS DURATION AGE
busybox-job 3/10 12s 12s
[root@k8s-master1 ~]# kubectl get job
NAME COMPLETIONS DURATION AGE
busybox-job 4/10 15s 15s
[root@k8s-master1 ~]# kubectl get job
NAME COMPLETIONS DURATION AGE
busybox-job 10/10 34s 48s
34秒左右结束
[root@master ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
busybox-job-5zn6l 0/1 Completed 0 34s
busybox-job-cm9kw 0/1 Completed 0 29s
busybox-job-fmpgt 0/1 Completed 0 38s
busybox-job-gjjvh 0/1 Completed 0 45s
busybox-job-krxpd 0/1 Completed 0 25s
busybox-job-m2vcq 0/1 Completed 0 41s
busybox-job-ncg78 0/1 Completed 0 47s
busybox-job-tbzz8 0/1 Completed 0 51s
busybox-job-vb99r 0/1 Completed 0 21s
busybox-job-wnch7 0/1 Completed 0 32s
一次性备份MySQL数据库
通过Job控制器创建应用备份MySQL数据库
- MySQL数据库准备
[root@nginx jobcontroller]# cat 00_mysql.yaml
apiVersion: v1
kind: Service
metadata:
name: mysql-test
namespace: default
spec:
ports:
- port: 3306
name: mysql
clusterIP: None
selector:
app: mysql-dump
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: db
namespace: default
spec:
selector:
matchLabels:
app: mysql-dump
serviceName: "mysql-test"
template:
metadata:
labels:
app: mysql-dump
spec:
nodeName: k8s-master3
containers:
- name: mysql
image: mysql:5.7
env:
- name: MYSQL_ROOT_PASSWORD
value: "abc123"
ports:
- containerPort: 3306
volumeMounts:
- mountPath: "/var/lib/mysql"
name: mysql-data
volumes:
- name: mysql-data
hostPath:
path: /opt/mysqldata
- 创建用于实现任务的资源清单文件
[root@nginx jobcontroller]# cat 03_job.yaml
apiVersion: batch/v1
kind: Job
metadata:
name: mysql-dump
spec:
template:
metadata:
name: mysql-dump
spec:
nodeName: k8s-master2
containers:
- name: mysql-dump
image: mysql:5.7
command: ["/bin/sh","-c","mysqldump --host=mysql-test -uroot -pabc123 --databases mysql > /root/mysql2022.sql"]
volumeMounts:
- mountPath: "/root"
name: mysql-data
restartPolicy: Never
volumes:
- name: mysql-data
hostPath:
path: /opt/mysqldump
2.3 CronJob
2.3.1 CronJob介绍
- 类似于Linux系统的crontab，在指定的时间周期运行相关的任务
- 时间格式：分时日月周
2.3.2 CronJob应用案例
周期性输出字符
- 编写YAML文件
[root@k8s-master1 ~]# vim cronjob.yml
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: cronjob1
spec:
schedule: "* * * * *" # 分时日月周
jobTemplate:
spec:
template:
spec:
containers:
- name: hello
image: busybox
args:
- /bin/sh
- -c
- date; echo hello kubernetes
imagePullPolicy: IfNotPresent
restartPolicy: OnFailure
[root@k8s-master1 ~]# kubectl apply -f cronjob.yml
cronjob.batch/cronjob1 created
[root@k8s-master1 ~]# kubectl get cronjob
NAME SCHEDULE SUSPEND ACTIVE LAST SCHEDULE AGE
cronjob1 * * * * * False 0 <none> 21s
[root@k8s-master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
cronjob-1564993080-qlbgv 0/1 Completed 0 2m10s
cronjob-1564993140-zbv7f 0/1 Completed 0 70s
cronjob-1564993200-gx5xz 0/1 Completed 0 10s
看AGE时间,每分钟整点执行一次
周期性备份MySQL数据库
- MySQL数据库准备
[root@nginx jobcontroller]# cat 00_mysql.yaml
apiVersion: v1
kind: Service
metadata:
name: mysql-test
namespace: default
spec:
ports:
- port: 3306
name: mysql
clusterIP: None
selector:
app: mysql-dump
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: db
namespace: default
spec:
selector:
matchLabels:
app: mysql-dump
serviceName: "mysql-test"
template:
metadata:
labels:
app: mysql-dump
spec:
nodeName: worker03
containers:
- name: mysql
image: mysql:5.7
env:
- name: MYSQL_ROOT_PASSWORD
value: "abc123"
ports:
- containerPort: 3306
volumeMounts:
- mountPath: "/var/lib/mysql"
name: mysql-data
volumes:
- name: mysql-data
hostPath:
path: /opt/mysqldata
- Cronjob控制器类型应用资源清单文件
[root@nginx jobcontroller]# cat 05_cronjob.yaml
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: mysql-dump
spec:
schedule: "*/1 * * * *"
jobTemplate:
spec:
template:
spec:
nodeName: worker02
containers:
- name: c1
image: mysql:5.7
command: ["/bin/sh","-c","mysqldump --host=mysql-test -uroot -pabc123 --databases mysql > /root/mysql`date +%Y%m%d%H%M`.sql"]
volumeMounts:
- name: mysql-data
mountPath: "/root"
restartPolicy: Never
volumes:
- name: mysql-data
hostPath:
path: /opt/mysqldump
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