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.comPassword: WARNING! Your password will be stored unencrypted in /root/.docker/config.json.Configure a credential helper to remove this warning. Seehttps://docs.docker.com/engine/reference/commandline/login/#credentials-storeLogin Succeeded[root@localhost demo]# docker build -t demo:2.0 .Sending build context to Docker daemon 17.57MBStep 1/4 : FROM openjdk:8-jdk-alpine ---> a3562aa0b991Step 2/4 : VOLUME /tmp ---> Using cache ---> a98cf1fbeb9dStep 3/4 : ADD ./demojenkins.jar demojenkins.jar ---> 12bfc15e5295Step 4/4 : ENTRYPOINT ["java","-jar","/demojenkins.jar", "&"] ---> Running in 2908dd94dfa7Removing intermediate container 2908dd94dfa7 ---> 3041db93b6dfSuccessfully built 3041db93b6dfSuccessfully tagged demo:2.0[root@localhost demo]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEdemo 2.0 3041db93b6df About a minute ago 122MBdemo 1.0 1952e02daef9 19 hours ago 122MB openjdk 8-jdk-alpine a3562aa0b991 3 years ago 105MBjava 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:2.0The 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 deploymentsNAME READY UP-TO-DATE AVAILABLE AGEjavademo1 3/3 3 3 19hnginx 1/1 1 1 5d21h# 查看 Deployment 上线状态[root@k8smaster ~]# kubectl rollout status deployment/javademo1deployment "javademo1" successfully rolled out# 查看 Deployment 对象创建的 ReplicaSet：[root@k8smaster ~]# kubectl get rsNAME DESIRED CURRENT READY AGE javademo1-84dd5c9485 3 3 3 4h25mnginx-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-labelsNAME READY STATUS RESTARTS AGE LABELSjavademo1-84dd5c9485-7vgkr 1/1 Running 0 4h20m app=javademo1,pod-template-hash=84dd5c9485javademo1-84dd5c9485-8ckk6 1/1 Running 0 4h26m app=javademo1,pod-template-hash=84dd5c9485javademo1-84dd5c9485-8hfmd 1/1 Running 0 4h20m app=javademo1,pod-template-hash=84dd5c9485nginx-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 podsNAME READY STATUS RESTARTS AGEjavademo1-84dd5c9485-7vgkr 1/1 Running 0 4h31mjavademo1-84dd5c9485-8ckk6 1/1 Running 0 4h37mjavademo1-84dd5c9485-8hfmd 1/1 Running 0 4h31mnginx-f89759699-5hkdw 1/1 Running 0 5d21h # 查看 Deployeement 详情[root@k8smaster ~]# kubectl describe deployment/javademo1Name: javademo1Namespace: defaultCreationTimestamp: Tue, 18 Oct 2022 18:51:25 +0800Labels: app=javademo1Annotations: deployment.kubernetes.io/revision: 2Selector: app=javademo1Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailableStrategyType: RollingUpdateMinReadySeconds: 0RollingUpdateStrategy: 25% max unavailable, 25% max surgePod Template: Labels: app=javademo1 Containers: vipsoft: Image: registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:1.0 Port: Host Port: Environment: Mounts: Volumes: Conditions: Type Status Reason ---- ------ ------ Progressing True NewReplicaSetAvailable Available True MinimumReplicasAvailableOldReplicaSets: NewReplicaSet: javademo1-84dd5c9485 (3/3 replicas created)Events: 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 [root@k8smaster ~]# kubectl set image deployment/javademo1 vipsoft=registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:2.0deployment.apps/javademo1 image updated[root@k8smaster ~]# kubectl rollout status deployment/javademo1deployment "javademo1" successfully rolled out[root@k8smaster ~]# 方法2
# 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/javademo1deployment "javademo1" edited查看已更新的 Deployment 的信息
[root@k8smaster ~]# kubectl get deploymentsNAME READY UP-TO-DATE AVAILABLE AGEjavademo1 3/3 3 3 20hnginx 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 rsNAME DESIRED CURRENT READY AGEjavademo1-5476dc8d7d 3 3 3 11mjavademo1-84dd5c9485 0 0 0 5h17mnginx-f89759699 1 1 1 5d22h#只有最新的 5476dc8d7d 信息[root@k8smaster ~]# kubectl get podsNAME READY STATUS RESTARTS AGEjavademo1-5476dc8d7d-bf6m5 1/1 Running 0 11mjavademo1-5476dc8d7d-ttt5b 1/1 Running 0 11mjavademo1-5476dc8d7d-zd4c7 1/1 Running 0 11mnginx-f89759699-5hkdw 1/1 Running 0 5d22h[root@k8smaster ~]# kubectl describe deployment/javademo1Name: javademo1Namespace: defaultCreationTimestamp: Tue, 18 Oct 2022 18:51:25 +0800Labels: app=javademo1Annotations: deployment.kubernetes.io/revision: 3Selector: app=javademo1Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailableStrategyType: RollingUpdateMinReadySeconds: 0RollingUpdateStrategy: 25% max unavailable, 25% max surgePod Template: Labels: app=javademo1 Containers: vipsoft: Image: registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:2.0 Port: Host Port: Environment: Mounts: Volumes: Conditions: Type Status Reason ---- ------ ------ Available True MinimumReplicasAvailable Progressing True NewReplicaSetAvailableOldReplicaSets: 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/javademo1deployment.apps/javademo1 REVISION CHANGE-CAUSE1 2 # 查看版本 2 的信息： [root@k8smaster ~]# kubectl rollout history deployment/javademo1 --revision=2deployment.apps/javademo1 with revision #2Pod Template: Labels: app=javademo1 pod-template-hash=84dd5c9485 Containers: vipsoft: Image: registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:1.0 Port: Host Port: Environment: Mounts: Volumes: # 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/javademo1deployment.apps/javademo1 rolled back[root@k8smaster ~]# kubectl describe deployment/javademo1Name: javademo1Namespace: defaultCreationTimestamp: Tue, 18 Oct 2022 18:51:25 +0800Labels: app=javademo1Annotations: deployment.kubernetes.io/revision: 4Selector: app=javademo1Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailableStrategyType: RollingUpdateMinReadySeconds: 0RollingUpdateStrategy: 25% max unavailable, 25% max surgePod Template: Labels: app=javademo1 Containers: vipsoft: Image: registry.cn-shanghai.aliyuncs.com/vipsoft/vipsoft:1.0 Port: Host Port: Environment: Mounts: Volumes: Conditions: Type Status Reason ---- ------ ------ Available True MinimumReplicasAvailable Progressing True NewReplicaSetAvailableOldReplicaSets: 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