K8S部署redis高可用

在Kubernetes上部署Redis高可用可以通过Redis Sentinel或Redis Cluster来实现。这里以Redis Sentinel为例，步骤如下：

1. 创建Redis Sentinel镜像

首先需要创建Redis Sentinel镜像，可以通过以下Dockerfile创建：

FROM redis:5.0.7-alpine

RUN apk add --no-cache --update curl

COPY sentinel.conf /etc/redis/sentinel.conf

CMD ["redis-sentinel", "/etc/redis/sentinel.conf"]

其中sentinel.conf是Redis Sentinel的配置文件，可以在其中设置Redis实例的地址、端口等信息。

2. 创建Redis StatefulSet

接着创建Redis StatefulSet，可以参考以下yaml文件：

apiVersion: v1
kind: Service
metadata:
  name: redis
spec:
  selector:
    app: redis
  ports:
  - name: redis
    port: 6379
    targetPort: 6379
  clusterIP: None
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: redis
spec:
  serviceName: redis
  replicas: 3
  selector:
    matchLabels:
      app: redis
  template:
    metadata:
      labels:
        app: redis
    spec:
      containers:
      - name: redis
        image: redis:5.0.7-alpine
        command:
        - redis-server
        - /etc/redis/redis.conf
        volumeMounts:
        - name: redis-config
          mountPath: /etc/redis
      - name: sentinel
        image: my-redis-sentinel:latest
        volumeMounts:
        - name: sentinel-config
          mountPath: /etc/redis
      volumes:
      - name: redis-config
        configMap:
          name: redis-config
      - name: sentinel-config
        configMap:
          name: sentinel-config
  volumeClaimTemplates:
  - metadata:
      name: data
      annotations:
        volume.beta.kubernetes.io/storage-class: "gp2"
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi

其中，StatefulSet中有两个容器：一个是Redis容器，一个是Redis Sentinel容器。Redis容器使用Redis官方镜像，Redis Sentinel容器使用自己创建的Redis Sentinel镜像。同时，还需要创建两个ConfigMap，一个用于Redis配置，一个用于Redis Sentinel配置。

3. 部署Redis Sentinel

最后部署Redis Sentinel，可以参考以下yaml文件：

apiVersion: apps/v1
kind: Deployment
metadata:
  name: redis-sentinel
spec:
  replicas: 3
  selector:
    matchLabels:
      app: redis-sentinel
  template:
    metadata:
      labels:
        app: redis-sentinel
    spec:
      containers:
      - name: redis-sentinel
        image: my-redis-sentinel:latest
        command:
        - redis-sentinel
        - /etc/redis/sentinel.conf
        volumeMounts:
        - name: sentinel-config
          mountPath: /etc/redis
      volumes:
      - name: sentinel-config
        configMap:
          name: sentinel-config

通过部署Redis Sentinel，可以实现Redis集群的高可用。如果Redis主节点出现故障，Redis Sentinel会自动将从节点升级为主节点，从而保证Redis集群的可用性。