SymptomsThe problem can happen in Active-Active Virtuozzo cluster environment. Parallels Infrastructure Manager does not show list of nodes correctly if the resource group with Master is moved to a server where Slave is already present.
ResolutionTo fix the issue it is necessary to perform the following set of actions:
1. Take offline all Virtuozzo groups on the server;
2. Bring online the group where the Master node is located;
3. Bring online rest of Virtuozzo groups with Slave nodes.