[MDEV-18594] wsrep_on should not be changeable at runtime Created: 2019-02-15  Updated: 2020-09-07  Resolved: 2020-09-02

Status: Closed
Project: MariaDB Server
Component/s: Galera
Fix Version/s: N/A

Type: Task Priority: Major
Reporter: Rick Pizzi Assignee: Julius Goryavsky
Resolution: Won't Fix Votes: 0
Labels: galera


 Description   

The wsrep_on variable can be changed at runtime with set global.
In a galera cluster this is very risky because if even a single statement
lands on the node while this variable is OFF, the entire cluster is compromised
as the change will not reach the other nodes.

(This actually happened at a customer of ours)

Please, make this variable only settable from config file at startup,
as there are no useful use cases to have this dynamic.

 Comments   
Comment by Jan Lindström (Inactive) [ 2019-03-28 ]

Do not think we can change this variable from dynamic to static on GA-releases.

Comment by Sergei Golubchik [ 2020-05-29 ]

I'm not even sure we should change it at all. It's a feature that some users might use. And it's protected by a specific privilege in 10.5, one cannot just change the variable unless one has privileges to do so.

Comment by Rick Pizzi [ 2020-05-29 ]

We have an use case to set it to OFF: when we need to bring up one node without having it be part of the cluster.
Very handy indeeed. But we do this by shutdown - change config - restart during maintenances and cluster upgrades.

Comment by Jan Lindström (Inactive) [ 2020-09-02 ]

My proposal would be that we do not do this change at all, setting set global wsrep_on=OFF has clear use cases. Changing parameter not changeable, would effect lot of mtr test cases so my estimation is based on fact that those need rewrite.

Comment by Rick Pizzi [ 2020-09-07 ]

jplindst what are these clear use cases?

Generated at Thu Feb 08 08:45:17 UTC 2024 using Jira 8.20.16#820016-sha1:9d11dbea5f4be3d4cc21f03a88dd11d8c8687422.