simultaneous graceful leaving of two nodes leaves one remaining in non-PC
Affects | Status | Importance | Assigned to | Milestone | ||
---|---|---|---|---|---|---|
Galera | Status tracked in 3.x | |||||
2.x |
Confirmed
|
Medium
|
Teemu Ollakka | |||
3.x |
Confirmed
|
Medium
|
Teemu Ollakka |
Bug Description
Sometimes when two out of three nodes leave the cluster almost simultaneously, the remaining node may end up in non-PC even if the nodes left gracefully.
Here is what happens:
1) Node 1 leaves the cluster, nodes 2 and 3 get the notification from EVS layer that node 1 left
2) Nodes 2 and 3 exchange states to form new PC view, but node 2 decides to leave just before message exchange is complete
3) Because forming new PC view was interrupted, node 3 loses the information that node 1 left gracefully, so final quorum computation for singleton view results non-PC
Expected behavior would be that the status of node 1 leaving gracefully would be preserved over intermediate view changes.
Note that if nodes 1 and 2 leave cluster so simultaneously that node 3 gets the notification of it in single view change or if nodes 2 and 3 finish the message exchange for new PC view before node 2 leaves, the outcome is that node 3 ends up in PC as expected.
Changed in galera: | |
assignee: | nobody → Teemu Ollakka (teemu-ollakka) |
description: | updated |
Changed in galera: | |
importance: | Undecided → Medium |
milestone: | none → 24.2.8 |
status: | New → Confirmed |
Changed in galera: | |
milestone: | 25.2.8 → 25.2.9 |
Presumably this never got fixed, or at least not fixed in a current release?