[Samba] CTDB: test network oscillations on the leader node, resulting in brain splitting

[Rowland Penny]

On 14/06/2023 02:15, tu.qiuping via samba wrote:
> My ctdb version is 4.17.7
> 
> 
> Hello, everyone.
> My ctdb cluster configuration is correct and the cluster is healthy before operation.
> My cluster has three nodes, namely 192.168.40.131（node 0）, 192.168.40.132（node 1）, and 192.168.40.133（node 2）. And the node 192.168.40.133 is the leader.
> 
> 
> I conducted network oscillation testing on node 192.168.40.133, and after a period of time, the lock update of this node failed, and at this time, the lock was taken away by node 0.
> Amazingly, after node 0 received the lock, it sent a message with leader=0 to node 1, but did not send it to node 2, even though the network of node 2 was healthy at this time.
> And when I restored the network of node 2, node 1 and node 2 kept trying to acquire the lock and reported an error: Unable to take cluster lock - contention.
> 
>

Can you please stop posting the same post to the list. If someone can 
help you and has time to do so, they will reply. Posting exactly the 
same post three times will not get you a faster response.

Rowland