Improved warning for Observer mode#7433
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neilalexander merged 1 commit intonats-io:mainfrom Oct 14, 2025
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Signed-off-by: Michael Röschter <michael@roeschter.de>
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This is purely a documentation/info update, which catches a situation where a correctly configured leaf cluster would fail to elect a meta leader, but the user would be left completely clueless as to why.
When a cluster is started the first time(!) it will check if leaf nodes connections to SYS are configured. If this is the case the leaf cluster MAY be an extension of a hub cluster. It cannot verify this until the connection is actually made and it can compare jetstream domains (its an extension only if the domains are the same)
As a result the cluster goes into "Observer mode" in which meta leader election is deferred till the hub is connection via a SYS leaf node connection.
BUT, not hint is printed on the FIRST start- only on the SECOND start of the cluster a hint was printed.
The /healthz probe fails with a 503 and no further details beyond
"JetStream has not established contact with a meta leader"This leaves the user completely clueless as to why the meta leader was not elected.
nats server report jetstreamalso gives no hint as to the reason.This change prints the extension_hint warning on first start and extends the explanation.
Signed-off-by: Michael Röschter michael@roeschter.de