Better leave_restart_consul #619
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estellesoulard
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Nice improvement of the rolling restart 👍 |
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Perform the consul leave on secondaries before leader .
Ensure the cluster failure tolerance is sufficient before proceeding with the next node.
SUMMARY
The current rolling restart runs on host in the inventory order, regardless of the leader status. The consul documentation recommends running rolling restarts on the leader last, for a good reason: if we restart the leader first, we then cause 2 switchovers in fast succession.
-> I added a check on consul leadership and a reordering of hosts before the rolling restart. This change aims at being non invasive: if there is no leader, the initial host order will be used.
The current rolling restarts waits for consul info to respond. However, this does not signify that the node has properly rejoined the cluster as an active voter, and if we proceed with the next consul leave in such a state, we will have an unbalanced cluster.
-> I replaced the consul info by a check on 'Failure Tolerance' status which should be >=1 before proceeding.