Deploy and relate of jenkins/jenkins-slave from charmstore with additional matrix authentication configured, slaves unable to start and connect

[moon127]

Deploy cs:jenkins (36) and cs:jenkins-slave (13) eg current in charm store with additional Matrix Authentication / security plugins.

juju add-relation jenkins jenkins-slave - both machines in the same model under local lxd provider or openstack in same tenant.

Jenkins slave is able to retrieve the .jar and agent.jnlp but fails to start with:

Oct 08 11:05:33 juju-a0c0ef-prod-jenkaas-is-4 bash[14930]: java.io.IOException: file:/var/lib/jenkins/agent.jnlp?encrypt=true doesn't look like a JNLP file; content type was null

This looks to be related to enabling security in /etc/default/jenkins-slave (via the relation):

JENKINS_SLAVE_SECRET="REDACTED"

JENKINS_ARGS="-jnlpUrl file:${JENKINS_JNLP} -secret ${JENKINS_SLAVE_SECRET}"

If we break the relation and set the master_url to same http://ip:8080> as was used via the relation, no security is set and with Matrix Auth setup allowing anonymous user to connect slave this works:

JENKINS_ARGS="-jnlpUrl file:${JENKINS_JNLP}"

This looks like an issue related to authentication, perhaps when Matrix Auth is configured - as will be be in many use cases.