SymptomsContainers migration from Virtuozzo 3.5.1 to Parallels Virtuozzo Containers 4.0 via Parallels Management Console fails with the following error:
Connection to remote host cannot be open or it is closed
CauseThe error means that two nodes simply cannot reach each other. This could be due to different transport protocols used in Virtuozzo 3.5.1 and Parallels VIrtuozzo Containers 4.0.
ResolutionFirst of all please ensure that compatibility mode is enabled on the node.
The second thing that must be consider: In case it is supposed to use Parallels Management Console (PMC) for both 3.5.1 and 4.0 Virtuozzo versions it is necessary to reregister Parallels Virtuozzo Containers 4.0 node in 3.x compatibility mode. To make so please remove it from PMC, then add it back:
When registration windows prompts, please enter IP address, vzagent0 as account and vzagent0 password as password , then click Options button.
The windows will be extended and Transport checkbox will appear - choose Secure Socket Shell tunnel to register node in 3.x compatibility mode, click Connect.
Once node is connected you will see the warning on the top of right PMC frame that says that compatibility mode is used.
Now it is possible to migrate containers(VEs) from 3.5.1 node to 4.0 using PMC.