If one has *just* removed a unit and adds a new unit immediately, the new unit often wins the leader election. This puts the charm into a state that it cannot recover from automatically, as the new unit is not yet a member of the cluster and therefore cannot add itself to the cluster.
TRIAGE:
Catch and log this edge case and provide an "add_instance" action to solve it.
This turns out to be an edge case.
If one has *just* removed a unit and adds a new unit immediately, the new unit often wins the leader election. This puts the charm into a state that it cannot recover from automatically, as the new unit is not yet a member of the cluster and therefore cannot add itself to the cluster.
TRIAGE:
Catch and log this edge case and provide an "add_instance" action to solve it.