k8s常用资源之rc资源
1.k8s资源常见操作
创建一个资源
kubectl create -f xxx.yaml
查看一个资源
kubectl get pod | rc
查看一个资源的详细过程
kubectl describe pos pod_name
删除一个资源
kubectl delete pod pod_name
kubectl delete -f xxx.yaml
编辑一个资源的配置文件
kubectl edit pod pod_name
2.rc资源
rc保证指定数量的pod始终存活，rc通过标签选择器来关联pod
rc创建的pod资源会均匀的分布在每个节点上，假如一个节点挂了，会立刻迁移到正常的节点上，始终保持pod资源存活，假如指定pod资源个数为5个，当挂了一个pod会立刻在创建一个新的pod，当多了一个pod会立马删除
删除多余pod资源时会删除存活时间最短的哪一个
rc在管理pod时通过 selector中定义的标签来管理pod的数量，如果pod标签与rc标签一致，rc则认为这是自己开启的pod会对它进行管理，当少的时候增加，多的时候删除
2.1.运行一个rc
1）辨析eyml文件
[root@k8s-master rc]# vim k8s_rc.yml
apiVersion: v1 //api版本
kind: ReplicationController //资源类型这里选择rc
metadata: //属性
name: nginxrc //rc资源的名称
spec:
replicas: 5 //启动几个pod资源
selector: //rc资源的标签
app: myweb
template: //定义pod资源的目标
metadata:
labels:
app: myweb //标签
spec:
containers:
- name: myweb //容器的名称
image: 192.168.81.240/k8s/nginx:1.15 //容器仓库地址
ports:
- containerPort: 80 //端口
2）创建rc资源
[root@k8s-master rc]# kubectl create -f k8s_rc.yml
replicationcontroller "nginxrc" created
3）查看rc资源
[root@k8s-master rc]# kubectl get rc
NAME DESIRED CURRENT READY AGE
nginxrc 5 5 5 16m
DESIRED表示要创建几个pod
CURRENT表示当前起来几个
READY表示准备好了几个
4）查看启动的pod，一共有5个
[root@k8s-master rc]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginxrc-5nd7q 1/1 Running 0 23s
nginxrc-f0np6 1/1 Running 0 24s
nginxrc-n7pg4 1/1 Running 0 23s
nginxrc-q0zln 1/1 Running 0 24s
nginxrc-tvzvj 1/1 Running 0 24s
5）查看pod资源是否均匀
[root@k8s-master rc]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE
nginx2 1/1 Running 0 2d 172.16.77.2 192.168.81.230
nginxrc-5nd7q 1/1 Running 0 7m 172.16.46.3 192.168.81.220
nginxrc-f0np6 1/1 Running 0 7m 172.16.46.4 192.168.81.220
nginxrc-ldtnz 1/1 Running 0 35s 172.16.77.5 192.168.81.230
nginxrc-n7pg4 1/1 Running 0 7m 172.16.77.3 192.168.81.230
nginxrc-q0zln 1/1 Running 0 7m 172.16.77.4 192.168.81.230
test 2/2 Running 3 51m 172.16.46.2 192.168.81.220
2.2.删除一个rc运行的pod资源
1)删除
[root@k8s-master rc]# kubectl delete pod nginxrc-tvzvj
pod "nginxrc-tvzvj" deleted
2)删除完再查看，发现还是启动了5个，始终保证有5个
[root@k8s-master rc]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginxrc-5nd7q 1/1 Running 0 6m
nginxrc-f0np6 1/1 Running 0 6m
nginxrc-ldtnz 1/1 Running 0 9s
nginxrc-n7pg4 1/1 Running 0 6m
nginxrc-q0zln 1/1 Running 0 6m
2.3.node节点异常自动迁移
1)模拟node节点故障
[root@k8s-master rc]# kubectl delete node 192.168.81.230
node "192.168.81.230" deleted
2)查看pod资源是否迁移
[root@k8s-master rc]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE
nginxrc-27rlw 1/1 Running 0 1m 172.16.46.5 192.168.81.220
nginxrc-2scm1 1/1 Running 0 1m 172.16.46.7 192.168.81.220
nginxrc-5nd7q 1/1 Running 0 8m 172.16.46.3 192.168.81.220
nginxrc-f0np6 1/1 Running 0 8m 172.16.46.4 192.168.81.220
nginxrc-n3q8j 1/1 Running 0 1m 172.16.46.6 192.168.81.220
2.4.模拟增加pod资源观察删除的资源
1)修改test pod资源的标签
标签一致rc才会进行统一管理，始终保持指定的pod数量
将此pod的标签更换为nginxrc一样的标签
修改第十行
[root@k8s-master rc]# kubectl edit pod test
app: myweb
pod "test" edited
2)观察
换之前的pod情况
[root@k8s-master rc]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE
nginxrc-27rlw 1/1 Running 0 1m 172.16.46.5 192.168.81.220
nginxrc-2scm1 1/1 Running 0 1m 172.16.46.7 192.168.81.220
nginxrc-5nd7q 1/1 Running 0 9m 172.16.46.3 192.168.81.220
nginxrc-f0np6 1/1 Running 0 9m 172.16.46.4 192.168.81.220
nginxrc-v8p5j 1/1 Running 0 1s 172.16.77.2 192.168.81.230
test 2/2 Running 3 53m 172.16.46.2 192.168.81.220
换之后的pod情况
[root@k8s-master rc]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE
nginxrc-27rlw 1/1 Running 0 2m 172.16.46.5 192.168.81.220
nginxrc-2scm1 1/1 Running 0 2m 172.16.46.7 192.168.81.220
nginxrc-5nd7q 1/1 Running 0 9m 172.16.46.3 192.168.81.220
nginxrc-f0np6 1/1 Running 0 9m 172.16.46.4 192.168.81.220
test 2/2 Running 3 54m 172.16.46.2 192.168.81.220
删除多余pod资源时会删除存活时间最短的那一个
2.5.rc一键升级和自动回滚
一键升级其实就是把之前的pod一个个停掉，然后在根据新的配置启动新pod
回滚就是把新版本退回到旧版本
语法配置：kubectl rolling-update nginxrc -f k8s_rc2.yml --update-period=10s
rolling-update：升级回滚都需要的关键字
nginxrc：表示对哪个资源进行升级或回滚
-f：指定yaml文件
–update-period=10s：默认是1分钟，我们用10s升级，1s回滚
2.5.1.将nginx1.13版本的rc资源升级为nginx1.15
1)查看旧版本的pod容器
[root@k8s-master rc]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE
nginxrc-ff9bc 1/1 Running 0 13m 172.16.16.2 192.168.81.230
nginxrc-h36p6 1/1 Running 0 13m 172.16.56.3 192.168.81.220
nginxrc-rqq14 1/1 Running 0 13m 172.16.16.3 192.168.81.230
nginxrc-ttqww 1/1 Running 0 13m 172.16.56.2 192.168.81.220
nginxrc-vqv6t 1/1 Running 0 13m 172.16.56.4 192.168.81.220
nginxrc2-cdvbf 1/1 Running 0 6s 172.16.16.4 192.168.81.230
[root@k8s-master rc]# curl -I 172.16.56.4
HTTP/1.1 200 OK
Server: nginx/1.13.12
2)将nginx1.13升级为1.15
编写1.15版本的yaml
[root@k8s-master rc]# vim k8s_rc2.yml
apiVersion: v1
kind: ReplicationController
metadata:
name: nginxrc2
spec:
replicas: 5
selector:
app: myweb2
template:
metadata:
labels:
app: myweb2
spec:
containers:
- name: myweb2
image: 192.168.81.240/k8s/nginx:1.15
ports:
- containerPort: 80
3)一键升级，启动一个新的停止一个旧的
[root@k8s-master rc]# kubectl rolling-update nginxrc -f k8s_rc2.yml --update-period=10s
Continuing update with existing controller nginxrc2.
Scaling up nginxrc2 from 1 to 5, scaling down nginxrc from 5 to 0 (keep 5 pods available, don't exceed 6 pods)
Scaling nginxrc down to 4
Scaling nginxrc2 up to 2
Scaling nginxrc down to 3
Scaling nginxrc2 up to 3
Scaling nginxrc down to 2
Scaling nginxrc2 up to 4
Scaling nginxrc down to 1
Scaling nginxrc2 up to 5
Scaling nginxrc down to 0
Update succeeded. Deleting nginxrc
replicationcontroller "nginxrc" rolling updated to "nginxrc2
4)查看nginx版本
[root@k8s-master rc]# curl -I 172.16.56.3
HTTP/1.1 200 OK
Server: nginx/1.15.12
操作步骤详图
升级前后yaml文件比对
2.5.2.将nginx1.15版本回滚到nginx1.13
[root@k8s-master rc]# kubectl rolling-update nginxrc2 -f k8s_rc.yml --update-period=1s
Continuing update with existing controller nginxrc.
Scaling up nginxrc from 1 to 5, scaling down nginxrc2 from 5 to 0 (keep 5 pods available, don't exceed 6 pods)
Scaling nginxrc2 down to 4
Scaling nginxrc up to 2
Scaling nginxrc2 down to 3
Scaling nginxrc up to 3
Scaling nginxrc2 down to 2
Scaling nginxrc up to 4
Scaling nginxrc2 down to 1
Scaling nginxrc up to 5
Scaling nginxrc2 down to 0
Update succeeded. Deleting nginxrc2
replicationcontroller "nginxrc2" rolling updated to "nginxrc"
[root@k8s-master rc]# curl -I 172.16.16.2 2>/dev/null | head -3
HTTP/1.1 200 OK
Server: nginx/1.13.12
Date: Sun, 19 Jul 2020 16:14:55 GMT
