Symptoms

Virtuozzo related task fails with the following error message
ERRCODE 5000 ERRCODE_MINOR -4 VZALib error, code: -4, msg: Connection to vzagent was closed
 

Cause

Most probably there are some network issues between POA management node and Service VPS of the Virtuozzo node, mentioned in the task.
 

Resolution

POA Management Node communicates with Service VPS (VPS with ID #1 on a registered node) using ssh protocol on port 22/tcp.
One may perform the following actions to investigate/fix such kind of issues:

1. Check connection between the Management Node and the Service VPS. Execute the following command on the Management Node: where svps_ip is IP address of Service VPS. The command above must connect successfully, otherwise - there are network issues to be addressed.

2. Try to restart VZAgent on Virtuozzo server: login to the node as root and run the command:

After that try to resubmit failed task in POA.

3. If the problem persists, try to login as vzagent0 user from the Management Node to the Service VPS:
If login fails it could mean that the node was not registered in POA yet or the corresponding RSA key was removed from the Service VPS. Keys can be checked in the folder ~vzagent0/.ssh/authorized_keys on the Service VPS (one could login there using vzctl enter 1 from the Virtuozzo node itself), the file authorized_keys should contain the content of /usr/local/pem/etc/ssh-keys/vem.key.sec.pub file from the Management Node as single line.

Additional information

1. It is recommended to have Virtuozzo Tools updated on the hardware node. Please install available updates for Virtuozzo Tools using the utility 'vzup2date'.

WARNING: Do not upgrade Virtuozzo to the next major version (4.x), it is not supported by POA yet.

See the following article for details about vzup2date usage: http://kb.parallels.com/1170

2. To determine IP address of the Service VPS, one may execute the command 'vzlist 1' on the Virtuozzo node, also it could be taken from the POA CP: Top > Service Director > Virtuozzo Manager > VPS Hardware Nodes > (node) > IP Address of Service VPS.