创建部署详见 Kubernetes(K8S) Deployment 部署 Pod
传统应用升级，一般是V1.0的jar包，有一个应对 1.0 的 shell 启动脚本。升级时，传 2.0 的 jar包，配置 2.0 的 shell 脚本。
执行顺序为，停1.0的服务，启2.0的服务，有问题时，把2.0停掉再执行 1.0的shell脚本，手动恢复到1.0 版本，服务多的情况下，就很崩溃，而且服务会中断不可用。
高并发、高可用系统普及的今天，服务的升级更新至少要做到“业务不中断”。而滚动更新(Rolling-update)恰是满足这一需求的一种系统更新升级方案。对于Kubernetes集群部署的Service来说，Rolling update就是指一次仅更新一个Pod，然后逐个进行更新，而不是在同一时刻将该Service下面的所有Pod shutdown，然后去更新，逐个更新可以避免将业务中断；
RollingUpdate命令：通过自动扩缩容实现自动滚动升级
指令格式：kubectl rolling-update 旧控制器 新控制器 --image=新镜像
1. 发布新版到阿里云镜像仓库
Last login: Tue Oct 18 16:39:53 2022 from 172.16.0.66
[root@localhost ~]# cd /opt/demo/
[root@localhost demo]# ll
总用量 17160
-rw-r--r--. 1 root root 17566582 10月 19 11:50 demojenkins.jar
-rw-r--r--. 1 root root 126 10月 18 17:56 Dockerfile
[root@localhost demo]# docker login --username=hiXXXXXX@aliyun.com registry.cn-shanghai.aliyuncs.com
Password:
WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store
Login Succeeded
[root@localhost demo]# docker build -t demo:2.0 .
Sending build context to Docker daemon 17.57MB
Step 1/4 : FROM openjdk:8-jdk-alpine
---> a3562aa0b991
Step 2/4 : VOLUME /tmp
---> Using cache
---> a98cf1fbeb9d
Step 3/4 : ADD ./demojenkins.jar demojenkins.jar
---> 12bfc15e5295
Step 4/4 : ENTRYPOINT ["java","-jar","/demojenkins.jar", "&"]
---> Running in 2908dd94dfa7
Removing intermediate container 2908dd94dfa7
---> 3041db93b6df
Successfully built 3041db93b6df
Successfully tagged demo:2.0
[root@localhost demo]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
demo 2.0 3041db93b6df About a minute ago 122MB
demo 1.0 1952e02daef9 19 hours ago 122MB
openjdk 8-jdk-alpine a3562aa0b991 3 years ago 105MB
java 8 d23bdf5b1b1b 5 years ago 643MB
[root@localhost demo]# docker tag 3041db93b6df registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:2.0
[root@localhost demo]# docker push registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:2.0
The push refers to repository [registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft]
c38fa2e9a247: Pushed
ceaf9e1ebef5: Layer already exists
9b9b7f3d56a0: Layer already exists
f1b5933fe4b5: Layer already exists
2.0: digest: sha256:785c4707e7e629d22b5609310d8f945c107b277b94925cc0dbebdb3621b size: 1159
[root@localhost demo]#
2. 查看现有Pod信息（升级后对比用）
# 查看创建的 Deployment 对象
[root@k8smaster ~]# kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
javademo1 3/3 3 3 19h
nginx 1/1 1 1 5d21h
# 查看 Deployment 上线状态
[root@k8smaster ~]# kubectl rollout status deployment/javademo1
deployment "javademo1" successfully rolled out
# 查看 Deployment 对象创建的 ReplicaSet：
[root@k8smaster ~]# kubectl get rs
NAME DESIRED CURRENT READY AGE
javademo1-84dd5c9485 3 3 3 4h25m
nginx-f89759699 1 1 1 5d21h
# 查看 Deployment 对象操作 ReplicaSet 创建的 Pod，并显示生成的标签：
[root@k8smaster ~]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
javademo1-84dd5c9485-7vgkr 1/1 Running 0 4h20m app=javademo1,pod-template-hash=84dd5c9485
javademo1-84dd5c9485-8ckk6 1/1 Running 0 4h26m app=javademo1,pod-template-hash=84dd5c9485
javademo1-84dd5c9485-8hfmd 1/1 Running 0 4h20m app=javademo1,pod-template-hash=84dd5c9485
nginx-f89759699-5hkdw 1/1 Running 0 5d21h app=nginx,pod-template-hash=f89759699
#查看当前运行的 Pod
[root@k8smaster ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
javademo1-84dd5c9485-7vgkr 1/1 Running 0 4h31m
javademo1-84dd5c9485-8ckk6 1/1 Running 0 4h37m
javademo1-84dd5c9485-8hfmd 1/1 Running 0 4h31m
nginx-f89759699-5hkdw 1/1 Running 0 5d21h
# 查看 Deployeement 详情
[root@k8smaster ~]# kubectl describe deployment/javademo1
Name: javademo1
Namespace: default
CreationTimestamp: Tue, 18 Oct 2022 18:51:25 +0800
Labels: app=javademo1
Annotations: deployment.kubernetes.io/revision: 2
Selector: app=javademo1
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=javademo1
Containers:
vipsoft:
Image: registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:1.0
Port: <none>
Host Port: <none>
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Progressing True NewReplicaSetAvailable
Available True MinimumReplicasAvailable
OldReplicaSets: <none>
NewReplicaSet: javademo1-84dd5c9485 (3/3 replicas created)
Events: <none>
Deployment, kubectl get deployments 所显示的字段有：
- NAME：列出了名字空间中 Deployment 的名称。
- READY：显示应用程序的可用的“副本”数。显示的模式是“就绪个数/期望个数”。
- UP-TO-DATE：显示为了达到期望状态已经更新的副本数。
- AVAILABLE：显示应用可供用户使用的副本数。
- AGE：显示应用程序运行的时间。
ReplicaSet, kubectl get rs 输出中包含以下字段：
- NAME：列出名字空间中 ReplicaSet 的名称；[Deployment名称]-[随机字符串]
- DESIRED：显示应用的期望副本个数，即在创建 Deployment 时所定义的值。 此为期望状态；
- CURRENT：显示当前运行状态中的副本个数；
- READY：显示应用中有多少副本可以为用户提供服务；
- AGE：显示应用已经运行的时间长度。
3. Deployment 升级
方法1
# 查看 Deployeement 详情 里可以看到 Containers 内容
# Containers:
# vipsoft:
# Image: registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:1.0
# 设置vipsoft容器中的镜像，镜像版本变了，就会触发重新拉取动作
[root@k8smaster ~]# kubectl set image deployment/javademo1 vipsoft=registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:2.0
deployment.apps/javademo1 image updated
[root@k8smaster ~]# kubectl rollout status deployment/javademo1
deployment "javademo1" successfully rolled out
[root@k8smaster ~]#
方法2：Jenkins 的时候比较常用，早期使用 Kubernetes Continuous Deploy 插件，现已重淘汰，可使用 Config File Provider 代替
# Containers:
# vipsoft:
# Image: registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:1.0 #将 ：1.0 改成 2.0
# 一旦镜像名（或 Pod 定义）发生了修改，则触发 k8s 系统完成 Deployment 所有运行 Pod 的滚动升级操作
[root@k8smaster ~]# kubectl edit deployment/javademo1
deployment "javademo1" edited
查看已更新的 Deployment 的信息
[root@k8smaster ~]# kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
javademo1 3/3 3 3 20h
nginx 1/1 1 1 5d22h
# 扩容了3个副本，将旧的 ReplicaSet 缩容到了 0 个副本，完成了Pod的升级
[root@k8smaster ~]# kubectl get rs
NAME DESIRED CURRENT READY AGE
javademo1-5476dc8d7d 3 3 3 11m
javademo1-84dd5c9485 0 0 0 5h17m
nginx-f89759699 1 1 1 5d22h
#只有最新的 5476dc8d7d 信息
[root@k8smaster ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
javademo1-5476dc8d7d-bf6m5 1/1 Running 0 11m
javademo1-5476dc8d7d-ttt5b 1/1 Running 0 11m
javademo1-5476dc8d7d-zd4c7 1/1 Running 0 11m
nginx-f89759699-5hkdw 1/1 Running 0 5d22h
[root@k8smaster ~]# kubectl describe deployment/javademo1
Name: javademo1
Namespace: default
CreationTimestamp: Tue, 18 Oct 2022 18:51:25 +0800
Labels: app=javademo1
Annotations: deployment.kubernetes.io/revision: 3
Selector: app=javademo1
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=javademo1
Containers:
vipsoft:
Image: registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:2.0
Port: <none>
Host Port: <none>
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: javademo1-5476dc8d7d (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 12m deployment-controller Scaled up replica set javademo1-5476dc8d7d to 1
Normal ScalingReplicaSet 11m deployment-controller Scaled down replica set javademo1-84dd5c9485 to 2
Normal ScalingReplicaSet 11m deployment-controller Scaled up replica set javademo1-5476dc8d7d to 2
Normal ScalingReplicaSet 11m deployment-controller Scaled down replica set javademo1-84dd5c9485 to 1
Normal ScalingReplicaSet 11m deployment-controller Scaled up replica set javademo1-5476dc8d7d to 3
Normal ScalingReplicaSet 11m deployment-controller Scaled down replica set javademo1-84dd5c9485 to 0
[root@k8smaster ~]#
上面 Events: 可以看出，先 up javademo1-5476dc8d7d to 1,再停 javademo1-84dd5c9485 to 2，Pod 逐个 滚动式更新，如下图:
Deployment 更新策略
在 Deployment 的定义中，可以通过 spec.strategy 指定 Pod 的更新策略，目前支持两种更新策略：
Recreate（重建）：设置 spec.strategy.type=Recreate，表示 Deployment 在更新 Pod 时，会先杀掉所有正在运行的 Pod，然后创建新的 Pod。
RollingUpdate（滚动更新）：设置 spec.strategy.type=RollingUpdate，表示 Deployment 会以滚动更新的方式来逐个更新 Pod。同时，可以通过设置 spec.strategy.rollingUpdate 下的两个参数（maxUnavailable 和 maxSurge）来控制滚动更新的过程。
4. Deployment 回滚
# 查看 Deployment 部署历史， CHANGE-CAUSE 里没有值，需要在创建 Deployment 时，使用 --record 参数，就可以在 CHANGE-CAUSE 列看到每个版本使用的命令了
[root@k8smaster ~]# kubectl rollout history deployment/javademo1
deployment.apps/javademo1
REVISION CHANGE-CAUSE
1 <none>
2 <none>
# 查看版本 2 的信息：
[root@k8smaster ~]# kubectl rollout history deployment/javademo1 --revision=2
deployment.apps/javademo1 with revision #2
Pod Template:
Labels: app=javademo1
pod-template-hash=84dd5c9485
Containers:
vipsoft:
Image: registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:1.0
Port: <none>
Host Port: <none>
Environment: <none>
Mounts: <none>
Volumes: <none>
# kubeetl rollout undo deployment/javademo1 --to-revision=2 加上参数，回滚到指定版本
# 这边没加参加，回滚到上一个版本
[root@k8smaster ~]# kubectl rollout undo deployment/javademo1
deployment.apps/javademo1 rolled back
[root@k8smaster ~]# kubectl describe deployment/javademo1
Name: javademo1
Namespace: default
CreationTimestamp: Tue, 18 Oct 2022 18:51:25 +0800
Labels: app=javademo1
Annotations: deployment.kubernetes.io/revision: 4
Selector: app=javademo1
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=javademo1
Containers:
vipsoft:
Image: registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:1.0
Port: <none>
Host Port: <none>
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: javademo1-84dd5c9485 (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 51m deployment-controller Scaled up replica set javademo1-5476dc8d7d to 1
Normal ScalingReplicaSet 50m deployment-controller Scaled down replica set javademo1-84dd5c9485 to 2
Normal ScalingReplicaSet 50m deployment-controller Scaled up replica set javademo1-5476dc8d7d to 2
Normal ScalingReplicaSet 50m deployment-controller Scaled up replica set javademo1-5476dc8d7d to 3
Normal ScalingReplicaSet 50m deployment-controller Scaled down replica set javademo1-84dd5c9485 to 1
Normal ScalingReplicaSet 50m deployment-controller Scaled down replica set javademo1-84dd5c9485 to 0
Normal ScalingReplicaSet 20s (x2 over 5h57m) deployment-controller Scaled up replica set javademo1-84dd5c9485 to 1
Normal ScalingReplicaSet 17s deployment-controller Scaled down replica set javademo1-5476dc8d7d to 2
Normal ScalingReplicaSet 17s deployment-controller Scaled up replica set javademo1-84dd5c9485 to 2
Normal ScalingReplicaSet 15s deployment-controller Scaled down replica set javademo1-5476dc8d7d to 1
Normal ScalingReplicaSet 14s (x2 over 5h51m) deployment-controller Scaled up replica set javademo1-84dd5c9485 to 3
Normal ScalingReplicaSet 9s deployment-controller Scaled down replica set javademo1-5476dc8d7d to 0
[root@k8smaster ~]#
history 中 CHANGE-CAUSE 里没有值，需要在创建 Deployment 时，使用 --record 参数，就可以在 CHANGE-CAUSE 列看到每个版本使用的命令了
看了很多贴子，这篇不错：Pod 的升级和回滚