搬移 redis via ENVOY

在前篇有談到幾個搬移 redis 的方法，其中的 master-slave 搬移多少還是有點不安全。在前篇最下方有提到，即使在 slave 複寫過期時間，還是會在 master 過期時同時被刪掉。

此文會搭配 envoy 來做到搬移，並且不用修改程式碼。

ref:

https://www.envoyproxy.io/

https://betterprogramming.pub/migrate-from-standalone-redis-to-redis-cluster-f45b219330a3

步驟

1. 建立新的 redis instance

create a new redis instance

2. 建立 envoy 當 redis proxy, 透過 envoy 的 request mirror, 可以將 request 送到兩個 redis

create a envoy as redis proxy

apiVersion: v1
kind: ConfigMap
metadata:
  name: redis-envoy-config
data:
  envoy.yaml: |-
    admin:
      access_log_path: "/dev/null"
      address:
        socket_address:
          protocol: TCP
          address: 0.0.0.0
          port_value: 8001
    static_resources:
      listeners:
      - name: redis_listener
        address:
          socket_address:
            protocol: TCP
            address: 0.0.0.0
            port_value: 6379
        filter_chains:
        - filters:
          - name: envoy.filters.network.redis_proxy
            typed_config:
              "@type": type.googleapis.com/envoy.extensions.filters.network.redis_proxy.v3.RedisProxy
              stat_prefix: redis_proxy
              settings:
                op_timeout: 5s
                enable_redirection: true
              prefix_routes:
                catch_all_route:
                  cluster: old_redis
                  request_mirror_policy:
                    cluster: new_redis
                    exclude_read_commands: true
      clusters:
      - name: old_redis
        connect_timeout: 3s
        type: STRICT_DNS
        dns_lookup_family: V4_ONLY
        load_assignment:
          cluster_name: old_redis
          endpoints:
          - lb_endpoints:
            - endpoint:
                address:
                  socket_address:
                    address: old_redis_address
                    port_value: old_redis_address_port
      - name: new_redis
        connect_timeout: 3s
        type: STRICT_DNS
        dns_lookup_family: V4_ONLY
        load_assignment:
          cluster_name: new_redis
          endpoints:
          - lb_endpoints:
            - endpoint:
                address:
                  socket_address:
                    address: new_redis_address
                    port_value: new_redis_address_port
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: redis-envoy
spec:
  replicas: 1
  selector:
    matchLabels:
      app: redis-envoy
  template:
    metadata:
      labels:
        app: redis-envoy
    spec:
      containers:
        - name: redis-envoy
          image: envoyproxy/envoy:v1.17.0
          volumeMounts:
            - name: config
              mountPath: /etc/envoy
          args:
            - "--config-path"
            - "/etc/envoy/envoy.yaml"
      volumes:
        - name: config
          configMap:
            name: redis-envoy-config
---
apiVersion: v1
kind: Service
metadata:
  name: redis-envoy
spec:
  clusterIP: None
  ports:
    - port: 6379
  selector:
    app: redis-envoy

3. 待搬移/同步後，直接連至新 redis

P.S.

透過 envoy 連線至 redis 並不是每個指令都能使用，記得先確認是否有用到其他指令

ref:

https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/other_protocols/redis#supported-commands