server-id verifiedimportantWritten by the Hub
Node identifier
in the configuration this is a line
server-id: …Number identifying this node, used to keep generated message identifiers unique across a cluster.
Values
- Values
positive integer- applying
restart required- where it can be set
in the config file · with a startup flag · as an environment variable
In detail
MailerQ generates a message id for any message that arrives without one — we saw it happen on the stand. In a cluster those ids must not collide, and this directive is what separates them. Documented with a default of 1, absent from the help output, accepted by the binary. A cluster where every node keeps the default is a cluster where two nodes can mint the same identifier, and the consequence is not a failure but something worse: two different messages that look like one in any system that keys on message id, including a customer's own reporting.
What happens if you get it wrong
Two nodes of one cluster left at the same value.Generated message identifiers can collide. Nothing breaks visibly; deduplication and reporting downstream quietly merge distinct messages.from the documentation · inference