Redis Sentinel client doesn't reconnect after connection failure

[BrianMwit]

Description

When using Redis Sentinel, after Redis Sentinel went down, Redis client doesn't reconnect after it come back online.
This is a regression we noticed when upgrading from @redis/client 5.8.3 to 5.9.0.

Minimal reproducible script: simply call client.get() every 3 seconds and print out the result

const { createSentinel } = require('@redis/client');
const client = createSentinel({
    name: 'mymaster',
    sentinelRootNodes: [{ host: '192.168.11.123', port: 26379 }],
    RESP: 3,
});
client
    .on('connect', () => console.info('Redis connected'))
    .on('end', () => {
        console.info('Redis disconnected, reconnecting');
        client.connect();
    })
    .on('error', (err) => console.error('Redis error: ' + err))
    .connect();

setInterval(async () => {
    const timestamp = new Date().toISOString();
    try {
        const results = await Promise.race([
            client.get('test-key'),
            new Promise((_, reject) => setTimeout(() => reject(new Error('1s Timeout')), 1000)),
        ]);
        console.log(`${timestamp} - Redis GET success: ${results}`);
    } catch (err) {
        console.log(`${timestamp} - Redis GET fail: ${err.message}`);
    }
}, 3000);

Example log of running the script -> shutdown Redis cluster (Sentinel, Master, Slave) -> restart the cluster
(or simply disconnecting - wait - reconnect ethernet cable)
v5.9.0

$ npm i @redis/client@5.9.0
$ node redis-disconnect.js
2025-11-05T14:01:22.293Z - Redis GET success: null
2025-11-05T14:01:25.295Z - Redis GET success: null
2025-11-05T14:01:28.301Z - Redis GET fail: 1s Timeout
2025-11-05T14:01:31.304Z - Redis GET fail: 1s Timeout
Redis error: obseve client error: Error: Connection timeout
Redis error: Error: Connection timeout
2025-11-05T14:01:34.311Z - Redis GET fail: 1s Timeout
Redis error: obseve client error: Error: Connection timeout
Redis error: Error: Connection timeout
Error: None of the sentinels are available
    at RedisSentinelInternal.observe (/.../node_modules/@redis/client/dist/lib/sentinel/index.js:759:15)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async #connect (/.../node_modules/@redis/client/dist/lib/sentinel/index.js:522:51)
2025-11-05T14:01:37.318Z - Redis GET fail: 1s Timeout
2025-11-05T14:01:40.325Z - Redis GET fail: 1s Timeout
Redis error: obseve client error: Error: Connection timeout
Redis error: Error: Connection timeout
2025-11-05T14:01:43.327Z - Redis GET fail: 1s Timeout
2025-11-05T14:01:46.329Z - Redis GET fail: 1s Timeout
Redis error: obseve client error: Error: Connection timeout
Redis error: Error: Connection timeout
Error: None of the sentinels are available
    at RedisSentinelInternal.observe (/.../node_modules/@redis/client/dist/lib/sentinel/index.js:759:15)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async #connect (/.../node_modules/@redis/client/dist/lib/sentinel/index.js:522:51)
2025-11-05T14:01:49.330Z - Redis GET fail: 1s Timeout

and it never recover, even after the Redis cluster is back online. We need to manually restart the app.

v5.8.3, it automatically reconnects just fine:

$ npm i @redis/client@5.8.3
$ node redis-disconnect.js
2025-11-05T14:06:12.746Z - Redis GET success: null
2025-11-05T14:06:15.746Z - Redis GET success: null
Redis error: obseve client error: Error: connect ECONNREFUSED 192.168.11.123:26379
Redis error: Error: connect ECONNREFUSED 192.168.11.123:26379
2025-11-05T14:06:21.751Z - Redis GET fail: 1s Timeout
2025-11-05T14:06:24.751Z - Redis GET fail: 1s Timeout
Redis error: obseve client error: Error: Connection timeout
Redis error: Error: Connection timeout
2025-11-05T14:06:27.754Z - Redis GET fail: 1s Timeout
Redis error: obseve client error: Error: Connection timeout
Redis error: Error: Connection timeout
Error: None of the sentinels are available
    at RedisSentinelInternal.observe (/.../node_modules/@redis/client/dist/lib/sentinel/index.js:752:15)
    at processTicksAndRejections (node:internal/process/task_queues:105:5)
    at runNextTicks (node:internal/process/task_queues:69:3)
    at process.processTimers (node:internal/timers:520:9)
    at async #connect (/.../node_modules/@redis/client/dist/lib/sentinel/index.js:522:51)
2025-11-05T14:06:30.758Z - Redis GET fail: 1s Timeout
Redis error: obseve client error: Error: connect ECONNREFUSED 192.168.11.123:26379
Redis error: Error: connect ECONNREFUSED 192.168.11.123:26379
2025-11-05T14:06:33.761Z - Redis GET fail: 1s Timeout
Redis error: obseve client error: Error: Connection timeout
Redis error: Error: Connection timeout
2025-11-05T14:06:36.764Z - Redis GET fail: 1s Timeout
2025-11-05T14:06:39.765Z - Redis GET fail: 1s Timeout
Redis error: obseve client error: Error: Connection timeout
Redis error: Error: Connection timeout
Error: None of the sentinels are available
    at RedisSentinelInternal.observe (/.../node_modules/@redis/client/dist/lib/sentinel/index.js:752:15)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async #connect (/.../node_modules/@redis/client/dist/lib/sentinel/index.js:522:51)
2025-11-05T14:06:42.769Z - Redis GET success: null
2025-11-05T14:06:45.775Z - Redis GET success: null

This may be related to #3108

(side note, notice how neither "Redis connected" nor "Redis disconnected" is in the log: #3012)

Adding

.on('end', () => {
    console.info('Redis disconnected, reconnecting');
    client.connect();
});

doesn't help either as the signal isn't triggered

Node.js Version

22.21.1

Redis Server Version

8.2.3

Node Redis Version

5.9.0

Platform

Linux

Logs

[nkaradzhov]

@BrianMwit thanks for raising this, i will take a look

[BrianMwit]

Can still be reproduced with @redis/client 5.10.0.

[ntvviktor]

Hey @BrianMwit, can you share how did you configure your sentinels cluster and the redis config, somehow I could not use a get, set with createSentinel() API

[oskarwilliams]

I get this issue too, and it is quite catastrophic to us.

[BrianMwit]

@ntvviktor I first got the issue with the Redis Cluster managed by other teams in the company, but am able to reproduce the issue in Redis Sentinel docker compose cluster as per this instruction: https://medium.com/@mohsenmahoski/setting-up-sentinel-with-docker-compose-5cad962c7643
A quick copy of the config https://gist.github.com/BrianMwit/f1181016ed97745d58a1fb780088fb6e

[mayankkapoor]

I'm getting this issue as well, quite a significant one for us. Have sent a PR for review to fix this.