k8s容器之deployment控制器镜像更新

vlambda
2022-04-20

k8s容器之deployment控制器镜像更新

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Deployment

支持ReplicaSet的所有功能；
支持发布的停止、继续；
支持滚动升级和回滚版本。

创建deployment

创建pc-deployment.yaml，内容如下：

apiVersion: apps/v1
kind: Deployment 
metadata:
 name: pc-deployment
 namespace: dev
spec: 
 replicas: 3
 selector:
   matchLabels:
     app: nginx-pod
 template:
   metadata:
     labels:
       app: nginx-pod
   spec:
     containers:
     - name: nginx
       image: nginx:1.17.1
yaml

# 创建deployment：

[root@k8s-master01 ~]# kubectl create -f pc-deployment.yaml --record=true
deployment.apps/pc-deployment created

# 查看deployment；

# UP-TO-DATE 最新版本的pod的数量；

# AVAILABLE 当前可用的pod的数量。

[root@k8s-master01 ~]# kubectl get deploy pc-deployment -n dev
NAME READY UP-TO-DATE AVAILABLE AGE
pc-deployment 3/3     3            3           15s

# 查看rs；

# 发现rs的名称是在原来deployment的名字后面添加了一个10位数的随机串。

[root@k8s-master01 ~]# kubectl get rs -n dev
NAME DESIRED CURRENT READY AGE
pc-deployment-6696798b78 3         3         3       23s

# 查看pod：

[root@k8s-master01 ~]# kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-deployment-6696798b78-d2c8n 1/1     Running 0          107s
pc-deployment-6696798b78-smpvp 1/1     Running 0          107s
pc-deployment-6696798b78-wvjd8 1/1     Running 0          107s

扩缩容

# 变更副本数量为5个：

[root@k8s-master01 ~]# kubectl scale deploy pc-deployment --replicas=5  -n dev
deployment.apps/pc-deployment scaled

# 查看deployment：

[root@k8s-master01 ~]# kubectl get deploy pc-deployment -n dev
NAME READY UP-TO-DATE AVAILABLE AGE
pc-deployment 5/5     5            5           2m

# 查看pod：

[root@k8s-master01 ~]# kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-deployment-6696798b78-d2c8n 1/1     Running 0          4m19s
pc-deployment-6696798b78-jxmdq 1/1     Running 0          94s
pc-deployment-6696798b78-mktqv 1/1     Running 0          93s
pc-deployment-6696798b78-smpvp 1/1     Running 0          4m19s
pc-deployment-6696798b78-wvjd8 1/1     Running 0          4m19s

# 编辑deployment的副本数量，修改spec:replicas: 4即可。

[root@k8s-master01 ~]# kubectl edit deploy pc-deployment -n dev
deployment.apps/pc-deployment edited

# 查看pod：

[root@k8s-master01 ~]# kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-deployment-6696798b78-d2c8n 1/1     Running 0          5m23s
pc-deployment-6696798b78-jxmdq 1/1     Running 0          2m38s
pc-deployment-6696798b78-smpvp 1/1     Running 0          5m23s
pc-deployment-6696798b78-wvjd8 1/1     Running 0          5m23s

镜像更新

deployment支持两种更新策略:重建更新和滚动更新,可以通过strategy指定策略类型,支持两个属性:

1. 重建更新

编辑pc-deployment.yaml,在spec节点下添加更新策略：

apiVersion: apps/v1
kind: Deployment
metadata:
 name: pc-deployment
 namespace: dev
spec:
 strategy: # 策略
   type: Recreate # 重建更新
 replicas: 3
 selector:
   matchLabels:
     app: nginx-pod
 template:
   metadata:
     labels:
       app: nginx-pod
   spec:
     containers:
     - name: nginx
       image: nginx:1.17.1
yaml

# 变更镜像：

[root@k8s-master01 ~]# kubectl set image deployment pc-deployment nginx=nginx:1.17.2 -n dev
deployment.apps/pc-deployment image updated

# 观察升级过程：

[root@k8s-master01 ~]# kubectl get pods -n dev -w
NAME READY STATUS RESTARTS AGE
pc-deployment-5d89bdfbf9-65qcw 1/1     Running 0          31s
pc-deployment-5d89bdfbf9-w5nzv 1/1     Running 0          31s
pc-deployment-5d89bdfbf9-xpt7w 1/1     Running 0          31s

pc-deployment-5d89bdfbf9-xpt7w 1/1     Terminating 0          41s
pc-deployment-5d89bdfbf9-65qcw 1/1     Terminating 0          41s
pc-deployment-5d89bdfbf9-w5nzv 1/1     Terminating 0          41s

pc-deployment-675d469f8b-grn8z 0/1     Pending 0          0s
pc-deployment-675d469f8b-hbl4v 0/1     Pending 0          0s
pc-deployment-675d469f8b-67nz2 0/1     Pending 0          0s

pc-deployment-675d469f8b-grn8z 0/1     ContainerCreating 0          0s
pc-deployment-675d469f8b-hbl4v 0/1     ContainerCreating 0          0s
pc-deployment-675d469f8b-67nz2 0/1     ContainerCreating 0          0s

pc-deployment-675d469f8b-grn8z 1/1     Running 0          1s
pc-deployment-675d469f8b-67nz2 1/1     Running 0          1s
pc-deployment-675d469f8b-hbl4v 1/1     Running 0          2s

2. 滚动更新

2.1 编辑pc-deployment.yaml,在spec节点下添加更新策略

apiVersion: apps/v1
kind: Deployment
metadata:
 name: pc-deployment
 namespace: dev
spec:
 strategy: # 策略
   type: RollingUpdate # 滚动更新策略
   rollingUpdate:
     maxSurge: 25% 
     maxUnavailable: 25%
 replicas: 3
 selector:
   matchLabels:
     app: nginx-pod
 template:
   metadata:
     labels:
       app: nginx-pod
   spec:
     containers:
     - name: nginx
       image: nginx:1.17.2
yaml

2.2 创建deploy进行验证

# 变更镜像：

[root@k8s-master01 ~]# kubectl set image deployment pc-deployment nginx=nginx:1.17.3 -n dev 
deployment.apps/pc-deployment image updated

# 观察升级过程：

[root@k8s-master01 ~]# kubectl get pods -n dev -w
NAME READY STATUS RESTARTS AGE
pc-deployment-c848d767-8rbzt 1/1     Running 0          31m
pc-deployment-c848d767-h4p68 1/1     Running 0          31m
pc-deployment-c848d767-hlmz4 1/1     Running 0          31m
pc-deployment-c848d767-rrqcn 1/1     Running 0          31m

pc-deployment-966bf7f44-226rx 0/1     Pending 0          0s
pc-deployment-966bf7f44-226rx 0/1     ContainerCreating 0          0s
pc-deployment-966bf7f44-226rx 1/1     Running 0          1s
pc-deployment-c848d767-h4p68 0/1     Terminating 0          34m

pc-deployment-966bf7f44-cnd44 0/1     Pending 0          0s
pc-deployment-966bf7f44-cnd44 0/1     ContainerCreating 0          0s
pc-deployment-966bf7f44-cnd44 1/1     Running 0          2s
pc-deployment-c848d767-hlmz4 0/1     Terminating 0          34m

pc-deployment-966bf7f44-px48p 0/1     Pending 0          0s
pc-deployment-966bf7f44-px48p 0/1     ContainerCreating 0          0s
pc-deployment-966bf7f44-px48p 1/1     Running 0          0s
pc-deployment-c848d767-8rbzt 0/1     Terminating 0          34m

pc-deployment-966bf7f44-dkmqp 0/1     Pending 0          0s
pc-deployment-966bf7f44-dkmqp 0/1     ContainerCreating 0          0s
pc-deployment-966bf7f44-dkmqp 1/1     Running 0          2s
pc-deployment-c848d767-rrqcn 0/1     Terminating 0          34m

# 至此，新版本的pod创建完毕，就版本的pod销毁完毕。

# 中间过程是滚动进行的，也就是边销毁边创建。

2.3 镜像更新中rs的变化

# 查看rs,发现原来的rs的依旧存在，只是pod数量变为了0，而后又新产生了一个rs，pod数量为4：

[root@k8s-master01 ~]# kubectl get rs -n dev
NAME DESIRED CURRENT READY AGE
pc-deployment-6696798b78 0         0         0       7m37s
pc-deployment-6696798b11 0         0         0       5m37s
pc-deployment-c848d76789 4         4         4       72s

版本回退

deployment支持版本升级过程中的暂停、继续功能以及版本回退等诸多功能。

kubectl rollout：版本升级相关功能，支持下面的选项：

status 显示当前升级状态；
history 显示升级历史记录；
pause 暂停版本升级过程；
resume 继续已经暂停的版本升级过程；
restart 重启版本升级过程；
undo 回滚到上一级版本（可以使用--to-revision回滚到指定版本）。

# 重新创建deploy，--record 记录deployment更新。

[root@master ~]# kubectl create -f pc-deployment.yaml --record

# 查看当前升级版本的状态：

[root@k8s-master01 ~]# kubectl rollout status deploy pc-deployment -n dev
deployment "pc-deployment" successfully rolled out

# 查看升级历史记录：

[root@k8s-master01 ~]# kubectl rollout history deploy pc-deployment -n dev
deployment.apps/pc-deployment
REVISION CHANGE-CAUSE
1         kubectl create --filename=pc-deployment.yaml --record=true
2         kubectl create --filename=pc-deployment.yaml --record=true
3         kubectl create --filename=pc-deployment.yaml --record=true

# 可以发现有三次版本记录，说明完成过两次升级。

# 版本回滚。

# 这里直接使用--to-revision=1回滚到了1版本，如果省略这个选项，就是回退到上个版本，就是2版本。

[root@k8s-master01 ~]# kubectl rollout undo deployment pc-deployment --to-revision=1 -n dev
deployment.apps/pc-deployment rolled back

# 查看发现，通过nginx镜像版本可以发现到了第一版。

[root@k8s-master01 ~]# kubectl get deploy -n dev -o wide
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES 
pc-deployment 4/4     4            4           74m   nginx nginx:1.17.1

# 查看rs，发现第一个rs中有4个pod运行，后面两个版本的rs中pod为运行。

# 其实deployment之所以可是实现版本的回滚，就是通过记录下历史rs来实现的。

# 一旦想回滚到哪个版本，只需要将当前版本pod数量降为0，然后将回滚版本的pod提升为目标数量就可以了。

[root@k8s-master01 ~]# kubectl get rs -n dev
NAME DESIRED CURRENT READY AGE
pc-deployment-6696798b78 4         4         4       78m
pc-deployment-966bf7f44 0         0         0       37m
pc-deployment-c848d767 0         0         0       71m

金丝雀发布(灰度发布)

Deployment控制器支持控制更新过程中的控制，如“暂停(pause)”或“继续(resume)”更新操作。

# 更新deployment的版本，并配置暂停deployment：

[root@k8s-master01 ~]# kubectl set image deploy pc-deployment nginx=nginx:1.17.4 -n dev && kubectl rollout pause deployment pc-deployment -n dev
deployment.apps/pc-deployment image updated
deployment.apps/pc-deployment paused

#观察更新状态：

[root@k8s-master01 ~]# kubectl rollout status deploy pc-deployment -n dev　
Waiting for deployment "pc-deployment" rollout to finish: 2 out of 4 new replicas have been updated...

# 监控更新的过程，可以看到已经新增了一个资源，但是并未按照预期的状态去删除一个旧的资源，就是因为使用了pause暂停命令。

[root@k8s-master01 ~]# kubectl get rs -n dev -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES 
pc-deployment-5d89bdfbf9 3         3         3       19m     nginx nginx:1.17.1   
pc-deployment-675d469f8b 0         0         0       14m     nginx nginx:1.17.2   
pc-deployment-6c9f56fcfb 2         2         2       3m16s nginx nginx:1.17.4   
[root@k8s-master01 ~]# kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-deployment-5d89bdfbf9-rj8sq 1/1     Running 0          7m33s
pc-deployment-5d89bdfbf9-ttwgg 1/1     Running 0          7m35s
pc-deployment-5d89bdfbf9-v4wvc 1/1     Running 0          7m34s
pc-deployment-6c9f56fcfb-996rt 1/1     Running 0          3m31s
pc-deployment-6c9f56fcfb-j2gtj 1/1     Running 0          3m31s

# 确保更新的pod没问题了，继续更新：

[root@k8s-master01 ~]# kubectl rollout resume deploy pc-deployment -n dev
deployment.apps/pc-deployment resumed

# 查看最后的更新情况：

[root@k8s-master01 ~]# kubectl get rs -n dev -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES 
pc-deployment-5d89bdfbf9 0         0         0       21m     nginx nginx:1.17.1   
pc-deployment-675d469f8b 0         0         0       16m     nginx nginx:1.17.2   
pc-deployment-6c9f56fcfb 4         4         4       5m11s nginx nginx:1.17.4   

[root@k8s-master01 ~]# kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-deployment-6c9f56fcfb-7bfwh 1/1     Running 0          37s
pc-deployment-6c9f56fcfb-996rt 1/1     Running 0          5m27s
pc-deployment-6c9f56fcfb-j2gtj 1/1     Running 0          5m27s
pc-deployment-6c9f56fcfb-rf84v 1/1     Running 0          37s

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