apache/druid · error · IllegalArgumentException

Invalid redis cluster configuration

Error message

Invalid redis cluster configuration: %s

What it means

RedisCacheFactory.create rejected a cluster node string that lacks a host:port separator (or has an empty host/port). While parsing the comma-separated cluster 'nodes' config each entry must be of the form host:port; a malformed entry cannot become a HostAndPort, so the factory raises an IAE naming the bad node string.

Solutions

1. Fix the druid.cache.cluster.nodes config so every entry is host:port (e.g. redis1:6379,redis2:6379).
2. Remove empty entries or trailing commas from the node list.
3. Validate the nodes string before deployment; split on commas and check each contains exactly one colon with non-empty parts.

When it happens

Trigger: Thrown at extensions-contrib/redis-cache/src/main/java/org/apache/druid/client/cache/RedisCacheFactory.java:51 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/bed924b278064d25. Report an issue: GitHub.

Appendix: source

Thrown at extensions-contrib/redis-cache/src/main/java/org/apache/druid/client/cache/RedisCacheFactory.java:51

import redis.clients.jedis.SslVerifyMode;

import java.util.Arrays;
import java.util.Set;
import java.util.stream.Collectors;

public class RedisCacheFactory
{
  public static Cache create(final RedisCacheConfig config)
  {
    if (config.getCluster() != null && StringUtils.isNotBlank(config.getCluster().getNodes())) {

      Set<HostAndPort> nodes = Arrays.stream(config.getCluster().getNodes().split(","))
                                     .map(String::trim)
                                     .filter(StringUtils::isNotBlank)
                                     .map(hostAndPort -> {
                                       int index = hostAndPort.indexOf(':');
                                       if (index <= 0 || index == hostAndPort.length()) {
                                         throw new IAE("Invalid redis cluster configuration: %s", hostAndPort);
                                       }

                                       int port;
                                       try {
                                         port = Integer.parseInt(hostAndPort.substring(index + 1));
                                       }
                                       catch (NumberFormatException e) {
                                         throw new IAE("Invalid port in %s", hostAndPort);
                                       }
                                       if (port <= 0 || port > 65535) {
                                         throw new IAE("Invalid port in %s", hostAndPort);
                                       }

                                       return new HostAndPort(hostAndPort.substring(0, index), port);
                                     }).collect(Collectors.toSet());

      ConnectionPoolConfig poolConfig = new ConnectionPoolConfig();
      poolConfig.setMaxTotal(config.getMaxTotalConnections());

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