redis/jedis · warning

Can not get master addr, master name

Error message

Can not get master addr, master name: {}. Sentinel: {}

What it means

During JedisSentinelPool initialization, the client asks each Sentinel for the current master address of masterName via SENTINEL get-master-addr-by-name. If a reachable Sentinel replies with null or an address list that isn't [host, port], this warning is logged and the loop continues to the next Sentinel. Initialization only fails if every Sentinel is exhausted (then JedisException 'Could not get a resource from the Sentinel' follows).

Solutions

1. Run `SENTINEL masters` (or `SENTINEL get-master-addr-by-name <name>`) on the Sentinel listed in the warning to check the name exists.
2. Fix the masterName in your client config to match the monitored name exactly (case-sensitive).
3. Ensure all Sentinels are configured with the same `sentinel monitor <name>` settings and can reach the master.
4. Wait for/verify Sentinel discovery — restart in a consistent order (master, replicas, sentinels).
5. Confirm the Sentinel port/auth in your sentinel list is correct so you are querying the intended Sentinel.

Example fix

// before
Set<String> sentinels = Set.of("sentinel1:26379", "sentinel2:26379");
JedisSentinelPool pool = new JedisSentinelPool("mymaster1", sentinels); // typo
// after
JedisSentinelPool pool = new JedisSentinelPool("mymaster", sentinels); // matches `sentinel monitor mymaster ...`

// verify before building the pool
try (Jedis s = new Jedis(sentinelHost, 26379)) {
  List<String> addr = s.sentinelGetMasterAddrByName(masterName);
  if (addr == null || addr.size() != 2) throw new IllegalArgumentException("unknown master: " + masterName);
}

try { pool = new JedisSentinelPool(masterName, sentinels); } catch (JedisException e) { /* all sentinels failed: check names/connectivity */ }

When it happens

Trigger: sentinelGetMasterAddrByName returns null or a list whose size != 2 from a live Sentinel — typically because masterName does not exist on that Sentinel, or the Sentinel hasn't finished discovering/monitoring the master.

Common situations: Typo in master name; Sentinels and master monitored under different names across environments; Sentinel started recently and hasn't learned the master yet; split network where some Sentinels know the master and others don't.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• Can not get master addr, master name
• Can connect to sentinel, but
• Can connect to sentinel, but
• Cannot get master address from sentinel running @
• Master name is required for Sentinel mode

AI-assisted analysis of redis/jedis@6dac31d4c2 (2026-09-08). Data as JSON: /api/errors/89ff08d5de2153db. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/redis/clients/jedis/JedisSentinelPool.java:264

    HostAndPort master = null;
    boolean sentinelAvailable = false;

    LOG.info("Trying to find master from available Sentinels...");

    for (HostAndPort sentinel : sentinels) {

      LOG.debug("Connecting to Sentinel {}", sentinel);

      try (Jedis jedis = new Jedis(sentinel, sentinelClientConfig)) {

        List<String> masterAddr = jedis.sentinelGetMasterAddrByName(masterName);

        // connected to sentinel...
        sentinelAvailable = true;

        if (masterAddr == null || masterAddr.size() != 2) {
          LOG.warn("Can not get master addr, master name: {}. Sentinel: {}", masterName, sentinel);
          continue;
        }

        master = toHostAndPort(masterAddr);
        LOG.debug("Found Redis master at {}", master);
        break;
      } catch (JedisException e) {
        // resolves #1036, it should handle JedisException there's another chance
        // of raising JedisDataException
        LOG.warn(
          "Cannot get master address from sentinel running @ {}. Reason: {}. Trying next one.", sentinel, e);
      }
    }

    if (master == null) {
      if (sentinelAvailable) {
        // can connect to sentinel, but master name seems to not monitored
        throw new JedisException("Can connect to sentinel, but " + masterName

View on GitHub (pinned to 6dac31d4c2)