apache/cassandra · error · IllegalStateException

Can't ignore local host %s when doing CMS migration

Error message

Can't ignore local host %s when doing CMS migration

What it means

upgradeFromGossip() migrates cluster management from gossip to TCM/CMS. The caller supplies a set of endpoints to ignore during the migration, but the local node itself must participate; if the local broadcast address appears in the ignored set, an IllegalStateException is thrown since the migrating node cannot exclude itself.

Source

Thrown at src/java/org/apache/cassandra/tcm/ClusterMetadataService.java:431

        }
        // otherwise, this is a noop.
        return preInit -> {
        };
    }

    public boolean isCurrentMember(InetAddressAndPort peer)
    {
        return ClusterMetadata.current().isCMSMember(peer);
    }

    public void upgradeFromGossip(List<String> ignoredEndpoints)
    {
        Set<InetAddressAndPort> ignored = ignoredEndpoints.stream().map(InetAddressAndPort::getByNameUnchecked).collect(toSet());
        if (ignored.contains(FBUtilities.getBroadcastAddressAndPort()))
        {
            String msg = String.format("Can't ignore local host %s when doing CMS migration", FBUtilities.getBroadcastAddressAndPort());
            logger.error(msg);
            throw new IllegalStateException(msg);
        }

        ClusterMetadata metadata = metadata();
        if (metadata.myNodeState() != NodeState.JOINED)
        {
            String msg = String.format("Initial CMS node needs to be fully joined, not: %s", metadata.myNodeState());
            logger.error(msg);
            throw new IllegalStateException(msg);
        }

        Set<InetAddressAndPort> existingMembers = metadata.fullCMSMembers();

        if (!metadata.directory.allAddresses().containsAll(ignored))
        {
            Set<InetAddressAndPort> allAddresses = Sets.newHashSet(metadata.directory.allAddresses());
            String msg = String.format("Ignored host(s) %s don't exist in the cluster", Sets.difference(ignored, allAddresses));
            logger.error(msg);
            throw new IllegalStateException(msg);

View on GitHub (pinned to 88fd0f6a0e)

Solutions

  1. Remove the local node's broadcast address from the ignored endpoints set and retry the migration.
  2. Verify resolved addresses (getByNameUnchecked may expand hostnames) do not include the local IP/port.
  3. Only ignore endpoints that are genuinely being decommissioned/removed, never the local node.

Example fix

// before
Set<InetAddressAndPort> ignored = endpoints.stream().map(InetAddressAndPort::getByNameUnchecked).collect(toSet());
cms.upgradeFromGossip(ignored); // includes local node
// after
Set<InetAddressAndPort> ignored = endpoints.stream().map(InetAddressAndPort::getByNameUnchecked)
                                            .filter(a -> !a.equals(FBUtilities.getBroadcastAddressAndPort()))
                                            .collect(toSet());
cms.upgradeFromGossip(ignored);
Defensive patterns

Strategy: validation

Validate before calling

Set<InetAddressAndPort> resolved = ignoredEndpoints.stream()
    .map(InetAddressAndPort::getByNameUnchecked).collect(toSet());
if (resolved.contains(FBUtilities.getBroadcastAddressAndPort()))
    throw new IllegalArgumentException("Cannot ignore local node during CMS migration");

Try / catch

try {
    cms.upgradeFromGossip(ignoredEndpoints);
} catch (IllegalStateException e) {
    logger.error("Fix ignore list: {}", e.getMessage());
}

Prevention

When it happens

Trigger: Calling ClusterMetadataService.upgradeFromGossip(ignoredEndpoints) where the set (after InetAddressAndPort resolution) contains FBUtilities.getBroadcastAddressAndPort().

Common situations: Operator error in nodetool/admin invocation listing the local node's IP among endpoints to ignore (e.g. decommissioning lists, copy-pasted ignore lists), or DNS/hostname resolution unexpectedly matching the local address.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/45ce548ede908e35. Report an issue: GitHub.