Spring Boot 2.3.0 新特性Redis 拓撲動態感應

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Spring Boot 2.3 新特性優雅停機詳解

Spring Boot 2.3 新特性分層 JAR

本篇是 spring boot v2.3 系列第三篇，來分享一下 v2.3 關於 spring data redis 的故障轉移優化。

背景

關於 Redis 在生產中咱們通常狀況下都會選擇 redis cluster 高可用架構部署，既能保證數據分片而且實現節點的故障自動轉移。 基本部署拓撲以下：

建立測試集羣

• 這裏經過我封裝的 pig4cloud/redis-cluster:4.0 鏡像，便可構建一個 6 個節點的 redis cluster 測試環境。

docker run --name redis-cluster -d -e CLUSTER_ANNOUNCE_IP=宿主機IP \
-p 7000-7005:7000-7005 -p 17000-17005:17000-17005  pig4cloud/redis-cluster:4.0

• 查看集羣節點信息

⋊> ./redis-cli -h 172.17.0.111 -p 7000 -c                     16:09:48
172.17.0.111:7000> cluster nodes
3d882206d40935beef84ff564b538d57369e4fd9 172.17.0.111:7003@17003 slave b8d24150df4a221c1045cd9a0696bd1972912d52 0 1591344590000 4 connected
b8d24150df4a221c1045cd9a0696bd1972912d52 172.17.0.111:7001@17001 master - 0 1591344590513 2 connected 5461-10922
c21167a6da7f8af31d2dd612d449cdf92ad2e7e9 172.17.0.111:7005@17005 slave 810baa140db6e008a137708f09d4335f5207ede3 0 1591344591000 6 connected
810baa140db6e008a137708f09d4335f5207ede3 172.17.0.111:7000@17000 myself,master - 0 1591344590000 1 connected 0-5460
05d2f9884d350a50ac9e38f575b57f19e864e74c 172.17.0.111:7004@17004 slave b3cf24a918d96a1949f49a1d7b3a965ff9dc858c 0 1591344590011 5 connected
b3cf24a918d96a1949f49a1d7b3a965ff9dc858c 172.17.0.111:7002@17002 master - 0 1591344591617 3 connected 10923-16383

應用層接入集羣

• 這裏使用 spring boot 2.2 演示， 默認的鏈接池使用 lettuce

spring:
  redis:
    cluster:
      nodes:
        - 172.17.0.111:7000
        - 172.17.0.111:7001
        - 172.17.0.111:7002
        - 172.17.0.111:7003
        - 172.17.0.111:7004
        - 172.17.0.111:7005

• 簡單使用 redisTemplate 操做集羣

@RestController
public class DemoController {
    @Autowired
    private RedisTemplate redisTemplate;

    @GetMapping("/add")
    public String redis() {
        redisTemplate.opsForValue().set("k1", "v1");
        return "ok";
    }
}

• 調用查看日誌

⋊> curl http://localhost:8080/add
ok⏎

咱們會發現操做 k1 是在 7000 節點進行操做寫入

[channel=0x5ff7aa8f, /172.17.0.156:50783 -> /172.17.0.111:7000, epid=0x8] write() writeAndFlush command ClusterCommand [command=AsyncCommand [type=SET, output=StatusOutput [output=null, error='null'], commandType=io.lettuce.core.protocol.Command], redirections=0, maxRedirections=5]
[channel=0x5ff7aa8f, /172.17.0.156:50783 -> /172.17.0.111:7000, epid=0x8] write() done

模擬單點故障

• 關閉 7000 節點

./redis-cli -h 172.17.0.111 -p 7000 -c
172.17.0.111:7000> SHUTDOWN

• 查看 redis cluster 集羣日誌 docker logs -f redis-cluster

咱們能夠看到此時集羣選舉完畢，完成故障轉移

23:S 05 Jun 08:24:49.387 # Starting a failover election for epoch 7.
29:M 05 Jun 08:24:49.388 # Failover auth granted to c21167a6da7f8af31d2dd612d449cdf92ad2e7e9 for epoch 7
26:M 05 Jun 08:24:49.388 # Failover auth granted to c21167a6da7f8af31d2dd612d449cdf92ad2e7e9 for epoch 7
23:S 05 Jun 08:24:49.389 # Failover election won: I'm the new master.
23:S 05 Jun 08:24:49.389 # configEpoch set to 7 after successful failover
23:M 05 Jun 08:24:49.389 # Setting secondary replication ID to 5253748ecf5bd7ab3536058fba8cad62d2d5e825, valid up to offset: 1622. New replication ID is 21d6a0b199a1ba655c0279d9c78f9682477ac9a3
23:M 05 Jun 08:24:49.389 * Discarding previously cached master state.
23:M 05 Jun 08:24:49.390 # Cluster state changed: ok

• 此時集羣狀態。7005 從 slave 變動爲 master
  

應用層日誌

• 大量輸出鏈接 7000 節點異常

io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: /172.17.0.111:7000
Caused by: java.net.ConnectException: Connection refused

io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: /172.17.0.111:7000
Caused by: java.net.ConnectException: Connection refused


io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: /172.17.0.111:7000
Caused by: java.net.ConnectException: Connection refused

• 再次操做 redisTemplate 會發現卡死，等待結果返回

⋊> curl http://localhost:8080/add

• 緣由分析

此時仍是操做 k1, 根據 slot 對應鏈接到 7000 節點，已經鏈接不到無限嘗試重連的問題。 lettuce 客戶端並未和 redis cluster 集羣狀態同步刷新，把宕機節點移除，完成故障轉移。

集羣拓撲動態感應

拓撲動態感應即客戶端可以根據 redis cluster 集羣的變化，動態改變客戶端的節點狀況，完成故障轉移。

咱們只須要在 spring boot 2.3.0 版本中 開啓此特性便可。

spring:
  redis:
    lettuce:
      cluster:
        refresh:
          adaptive: true

• 其實 lettuce 官方一直有這個功能，但 spring data redis 並未跟進，具體內容能夠參考 user-content-refreshing-the-cluster-topology-view 章節

舊版本兼容

咱們只須要參考 adaptive 開關打開後作了哪些事情，給本身的項目配置上 topology-view 便可

@Bean
	public LettuceConnectionFactory redisConnectionFactory(RedisProperties redisProperties) {
		RedisClusterConfiguration redisClusterConfiguration = new RedisClusterConfiguration(redisProperties.getCluster().getNodes());

		// https://github.com/lettuce-io/lettuce-core/wiki/Redis-Cluster#user-content-refreshing-the-cluster-topology-view
		ClusterTopologyRefreshOptions clusterTopologyRefreshOptions = ClusterTopologyRefreshOptions.builder()
				.enablePeriodicRefresh()
				.enableAllAdaptiveRefreshTriggers()
				.refreshPeriod(Duration.ofSeconds(5))
				.build();

		ClusterClientOptions clusterClientOptions = ClusterClientOptions.builder()
				.topologyRefreshOptions(clusterTopologyRefreshOptions).build();

		// https://github.com/lettuce-io/lettuce-core/wiki/ReadFrom-Settings
		LettuceClientConfiguration lettuceClientConfiguration = LettuceClientConfiguration.builder()
				.readFrom(ReadFrom.REPLICA_PREFERRED)
				.clientOptions(clusterClientOptions).build();

		return new LettuceConnectionFactory(redisClusterConfiguration, lettuceClientConfiguration);
	}

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