383 lines
8.2 KiB
Markdown
383 lines
8.2 KiB
Markdown
> 本文作者：丁辉
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# Deployment的使用
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[官方文档](https://kubernetes.io/zh-cn/docs/tutorials/kubernetes-basics/deploy-app/deploy-intro/)
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## 命令部署一个应用
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```bash
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kubectl create deployment nginx --image=nginx:alpine
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```
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## Yaml 部署一个 Deployment 应用
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1. 部署应用(最小化 Yaml)
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```yaml
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cat <<EOF | kubectl apply -f -
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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name: nginx-deployment
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labels:
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app: nginx
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spec:
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replicas: 3
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selector:
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matchLabels:
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app: nginx
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template:
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metadata:
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labels:
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app: nginx
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spec:
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containers:
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- name: nginx
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image: nginx:alpine
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ports:
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- containerPort: 80
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EOF
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```
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2. 验证
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```bash
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kubectl get deployments
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```
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## 更新和回滚
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> Deployment 支持两种更新策略：滚动更新（RollingUpdate，默认）和删除式更新（Recreate，又称单批次更新）。
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- ReCreate
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**删除式更新（Recreate）**：更新时先删除所有运行中的 Pod，待其彻底终止后创建新 ReplicaSet 及对应 Pod，更新期间服务暂不可用。
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```yaml
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spec:
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strategy:
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type: Recreate
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```
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- RollingUpdate
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**滚动更新（RollingUpdate）**：分批更新 Pod，待一批更新后的 Pod 就绪后再更新下一批，实现服务不中断；更新过程中会存在新老版本应用共存的情况，不同客户端可能获取不同版本响应。
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```yaml
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spec:
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strategy:
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type: RollingUpdate
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```
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### 更新
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1. 更新镜像
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在这里，`deployment/nginx-deployment` 表明 Deployment 的名称，`nginx` 表明需要进行更新的容器， 而 `nginx:latest` 则表示镜像的新版本以及它的标签。
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```bash
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kubectl set image deployment/nginx-deployment nginx=nginx:latest
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```
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2. 查看进度
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```bash
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kubectl rollout status deployment/nginx-deployment
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```
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3. 查看状态
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```bash
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kubectl get rs
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```
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### 回滚
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1. 查看 Deployment 修订历史
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```bash
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kubectl rollout history deployment/nginx-deployment
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```
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设置 `CHANGE-CAUSE` 消息
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```bash
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kubectl annotate deployment/nginx-deployment kubernetes.io/change-cause="image updated to latest"
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```
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2. 查看修订历史的详细信息
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```bash
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kubectl rollout history deployment/nginx-deployment --revision=2
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```
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3. 回滚
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```bash
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kubectl rollout undo deployment/nginx-deployment
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```
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或回滚到特定版本
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```bash
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kubectl rollout undo deployment/nginx-deployment --to-revision=2
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```
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### 重启
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```bash
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kubectl rollout restart deployment deployment/nginx-deployment
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```
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### 副本数调整
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```bash
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kubectl scale deployment/nginx-deployment --replicas=3
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```
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## 暂停、恢复 Deployment 的上线过程
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1. 暂停上线
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```bash
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kubectl rollout pause deployment/nginx-deployment
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```
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2. 更新 Deployment 镜像
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```bash
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kubectl set image deployment/nginx-deployment nginx=nginx:latest
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```
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你可以根据需要执行很多更新操作，例如，可以要使用的资源
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```bash
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kubectl set resources deployment/nginx-deployment -c=nginx --limits=cpu=200m,memory=512Mi
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```
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3. 最终，恢复 Deployment 上线并观察新的 ReplicaSet 的创建过程，其中包含了所应用的所有更新
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```bash
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kubectl rollout resume deployment/nginx-deployment
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```
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4. 监视上线的状态，直到完成
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```bash
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watch kubectl get rs
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```
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## 更新失败标记为 **"Failed"** 状态
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```bash
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kubectl patch deployment/nginx-deployment -p '{"spec":{"progressDeadlineSeconds":600}}'
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```
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`progressDeadlineSeconds`
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- **作用**: 定义 Deployment 滚动更新（Rolling Update）的最大允许时间
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- **值 600**: 表示 600 秒（1 分钟）
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- **默认值**: 通常为 600 秒，但显式设置可确保明确性
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- **工作逻辑**:
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1. 当 Deployment 开始更新（如镜像版本升级）时启动计时
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2. 如果更新过程超过 600 秒仍未完成
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3. Kubernetes 会将 Deployment 标记为 **"Failed"** 状态
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4. 并自动回滚到之前的稳定版本（如果配置了回滚策略）
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## 配置 ReplicaSet 清理策略
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你可以在 Deployment 中设置 `.spec.revisionHistoryLimit` 字段以指定保留此 Deployment 的多少个旧有 ReplicaSet。其余的 ReplicaSet 将在后台被垃圾回收。 默认情况下，此值为 10。
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```bash
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kubectl patch deployment/nginx-deployment -p '{"spec":{"revisionHistoryLimit":10}}'
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```
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## 金丝雀部署
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[官方文档](https://kubernetes.io/zh-cn/docs/concepts/workloads/controllers/deployment/#canary-deployment)
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### 通过副本数控制
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**操作步骤：**
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1. 先部署稳定版本（v1，9个副本）
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2. 部署金丝雀版本（v2，1个副本）
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3. Service会自动将约9%的流量（1/10）导向v2
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4. 观察监控，如果v2正常，逐步增加v2副本数，减少v1副本数
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1. 部署 Pod-1
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```yaml
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cat <<EOF | kubectl apply -f -
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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name: nginx-deployment-1
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labels:
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app: nginx
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spec:
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replicas: 9
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strategy:
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type: RollingUpdate
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selector:
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matchLabels:
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app: nginx
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template:
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metadata:
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labels:
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app: nginx
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version: v1
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spec:
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containers:
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- name: nginx
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image: registry.cn-hangzhou.aliyuncs.com/offends/demo:nginx-alpine-v1
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ports:
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- containerPort: 80
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EOF
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```
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2. 部署 Pod-2
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```yaml
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cat <<EOF | kubectl apply -f -
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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name: nginx-deployment-2
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labels:
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app: nginx
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spec:
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replicas: 1
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strategy:
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type: RollingUpdate
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selector:
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matchLabels:
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app: nginx
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template:
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metadata:
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labels:
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app: nginx
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version: v2
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spec:
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containers:
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- name: nginx
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image: registry.cn-hangzhou.aliyuncs.com/offends/demo:nginx-alpine-v2
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ports:
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- containerPort: 80
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EOF
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```
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3. 部署 Service（同时选择v1和v2的Pod）
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```yaml
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cat <<EOF | kubectl apply -f -
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apiVersion: v1
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kind: Service
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metadata:
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name: nginx-deployment-service
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spec:
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selector:
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app: nginx # 同时选择两个版本的Pod
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ports:
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- port: 80
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targetPort: 80
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EOF
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```
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4. 修改权重将流量导向 v2
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- 增加 v2
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```bash
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kubectl scale deployment/nginx-deployment-2 --replicas=10
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```
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- 降低 v1
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```bash
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kubectl scale deployment/nginx-deployment-1 --replicas=0
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```
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### 通过 Ingress 实现基于权重的金丝雀
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方法类似于前者，只是对象从副本数变换为 Ingress控制
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1. 创建两个 Service
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```bash
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cat <<EOF | kubectl apply -f -
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apiVersion: v1
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kind: Service
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metadata:
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name: nginx-deployment-service-1
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spec:
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selector:
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app: nginx
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version: v1
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ports:
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- port: 80
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targetPort: 80
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---
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apiVersion: v1
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kind: Service
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metadata:
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name: nginx-deployment-service-2
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spec:
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selector:
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app: nginx
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version: v2
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ports:
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- port: 80
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targetPort: 80
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EOF
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```
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2. 创建 Ingress 资源
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```yaml
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cat <<EOF | kubectl apply -f -
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# 金丝雀 Ingress 对象为 v1 版本
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apiVersion: networking.k8s.io/v1
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kind: Ingress
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metadata:
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name: nginx-ingress-1
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spec:
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rules:
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- host: demo.offends.cn
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http:
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paths:
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- path: /
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pathType: Prefix
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backend:
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service:
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name: nginx-deployment-service-1
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port:
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number: 80
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---
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# 金丝雀 Ingress 对象为 v2 版本
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apiVersion: networking.k8s.io/v1
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kind: Ingress
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metadata:
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name: nginx-ingress-2
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annotations:
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nginx.ingress.kubernetes.io/canary: "true"
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nginx.ingress.kubernetes.io/canary-weight: "10" # 10%流量到金丝雀
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spec:
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rules:
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- host: demo.offends.cn
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http:
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paths:
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- path: /
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pathType: Prefix
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backend:
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service:
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name: nginx-deployment-service-2
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port:
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number: 80
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EOF
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```
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3. 慢慢调整 nginx-ingress-2 流量到 100%，即完成更新
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