Go微服务架构实战 中篇：3. 扩缩容、自愈和故障转移、滚动更新
Go微服务架构实战-【公粽号：堆栈future】
1. 微服务架构上篇
1. grpc技术介绍
2. grpc+protobuf+网关实战
3. etcd技术介绍
4. 基于etcd的服务发现与注册
5. 基于etcd的分布式锁实战
2. 微服务架构中篇
基于k8s的Deployment工作负载
主要是利用Deployment资源对象实现的，包括一下功能：
- 多副本集
- 扩缩容
- 自愈和故障转移
- 滚动更新
- 回退能力
接下来详细了解下操作过程
1. 多副本集
deploy.yaml中只需修改一下replicas，让它的值变成我们想要的副本数量。
<pre data-tool="mdnice编辑器" style="box-sizing: border-box !important; margin: 10px 0px; padding: 0px; outline: 0px; font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; font-size: 14px; overflow: auto; display: block; color: rgb(33, 37, 41); max-width: 100%; overflow-wrap: break-word !important; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: 0.8px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0.8px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; border-radius: 5px; box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;">apiVersion: apps/v1 kind: Deployment metadata: name: k8sdemo-deploy labels: app: k8sdemo spec: replicas: 3 //修改这里 selector: matchLabels: app: k8sdemo template: metadata: labels: app: k8sdemo spec: containers: - name: k8sdemo image: k8s-grpc-demo:latest imagePullPolicy: Never ports: - containerPort: 50007 </pre>
然后kubectl apply -f deploy.yaml应用一下就可以了，看下创建结果：
image.gif
从结果看出三个pod成功起来了。
2. 扩缩容
比较简单，一行命令搞定：
kubectl scale --replicas=1 deployment/k8sdemo-deploy回车之后打印如下：
image.gif
然后看下pod数量kubectl get pod发现只有一个pod了，这里就不展示了，非常简单。
3. 自愈和故障转移
因为我只有一台机器，没办法验证，所以只列出步骤，下去大家自己可以尝试。
- 停某一台机器
- 删除某个pod
大家可以去试试，看看是否停掉机器之后，pod会在别的机器上再起来，保持Deployment的副本集数量不变。或者在某台机器上删除某个pod之后，看看这个pod是否重新建立(归功于Deployment的能力)。
tips：当你要删除pod的时候发现一直删除不掉，pod会自动起来，不要着急莫慌，你应该先删除Deployment，这样pod就会自动删除的。
4. 滚动更新
首先你基于你的代码做了部分更新，比如增加了日志等功能，然后在本地构建镜像，比如k8s-grpc-demo:v2，然后你用一行命令就可以搞定滚动更新：
<pre data-tool="mdnice编辑器" style="box-sizing: border-box !important; margin: 10px 0px; padding: 0px; outline: 0px; font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; font-size: 14px; overflow: auto; display: block; color: rgb(33, 37, 41); max-width: 100%; overflow-wrap: break-word !important; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: 0.8px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0.8px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; border-radius: 5px; box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;">kubectl set image deployment/k8sdemo-deploy k8s-grpc-demo=k8s-grpc-demo:v2 --record </pre>
查看下更新状态
<pre data-tool="mdnice编辑器" style="box-sizing: border-box !important; margin: 10px 0px; padding: 0px; outline: 0px; font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; font-size: 14px; overflow: auto; display: block; color: rgb(33, 37, 41); max-width: 100%; overflow-wrap: break-word !important; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: 0.8px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0.8px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; border-radius: 5px; box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;">kubectl rollout status deployment/k8sdemo-deploy </pre>
图片
5. 回退能力
- 查看历史版本记录
<pre data-tool="mdnice编辑器" style="box-sizing: border-box !important; margin: 10px 0px; padding: 0px; outline: 0px; font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; font-size: 14px; overflow: auto; display: block; color: rgb(33, 37, 41); max-width: 100%; overflow-wrap: break-word !important; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: 0.8px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0.8px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; border-radius: 5px; box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;">kubectl rollout history deployment/k8sdemo-deploy </pre>
图片
- 查看某个历史详情
<pre data-tool="mdnice编辑器" style="box-sizing: border-box !important; margin: 10px 0px; padding: 0px; outline: 0px; font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; font-size: 14px; overflow: auto; display: block; color: rgb(33, 37, 41); max-width: 100%; overflow-wrap: break-word !important; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: 0.8px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0.8px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; border-radius: 5px; box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;">kubectl rollout history deployment/k8sdemo-deploy --revision=2 </pre>
图片
- 回滚(回到上次)
<pre data-tool="mdnice编辑器" style="box-sizing: border-box !important; margin: 10px 0px; padding: 0px; outline: 0px; font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; font-size: 14px; overflow: auto; display: block; color: rgb(33, 37, 41); max-width: 100%; overflow-wrap: break-word !important; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: 0.8px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0.8px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; border-radius: 5px; box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;">kubectl rollout undo deployment/k8sdemo-deploy </pre>
- 回滚(回到指定版本)
<pre data-tool="mdnice编辑器" style="box-sizing: border-box !important; margin: 10px 0px; padding: 0px; outline: 0px; font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; font-size: 14px; overflow: auto; display: block; color: rgb(33, 37, 41); max-width: 100%; overflow-wrap: break-word !important; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: 0.8px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0.8px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; border-radius: 5px; box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;">kubectl rollout undo deploymen/k8sdemo-deploy --to-revision=2 </pre>
6. 小结
其实k8s使用不是很复杂，你可以学完k8s之后搭建自己的服务，但是如果想深入定制k8s，需要有一定golang知识和容器化知识，所以想要进阶的可以在深入学习下源码理解下原理。
下篇文章继续给大家讲解下k8s的service的服务注册和发现能力和ingress的入口网关能力，以及它们的网络架构知识。喜欢这篇文章的童鞋可以关注，转发和分享哈。
github地址：https://github.com/guojiangli/k8s-grpc-demo
【公粽号：堆栈future】
