A VPS-related task fails in Parallels Operations Automation (POA) with the following error message:
Connection to VZAgent was closed: poll_write efds
The same issue may cause inability to login to VZPP with the following error in CP:
There is no host with ID=xxx.
This is a general error message that indicates a problem with the connection from POA to the Virtuozzo Agent (VZAgent, PVA Agent) on the Parallels Virtuozzo Containers (PVC) server where the container is running.
There are several possible causes:
The PVC server is not available. For example, it has been turned off or some critical error occurred on a server, causing it to hang
The VZAgent service is not running on the PVC server
TCP ports 4433/4434 are closed in the firewall on the PVC server (or on intermediate routers in the datacenter), so POA cannot establish a connection to VZAgent
An unsupported PVC version has been installed
- The root credentials for the PVC server do not correspond with the credentials in the POA database
Check the POA VPS Hosting Deployment Guide to ensure a supported PVC version is installed on the PVC server.
Perform these basic operations to find out whether the PVC server is available from POA:
Ping the PVC server from the POA Management Node
Check you can log into the PVC server by SSH/RDP
telnetutility on the POA Management Node to check connectivity to ports 22 (SSH) or 3389 (RDP)
tracerouteto check the routing path from POA to the PVC server
- Use KVM/local console to check the server status if possible
Check if ports 4433/4434 are being listened to locally on the PVC server:
> netstat -ano | findstr ":443"
# netstat -antp | grep ":443"
Check the status of the VZAgent service on the PVC server and start it if it is not running:
> net start | findstr "Agent"
# vzagent_ctl status # pvaagent status
Use the basic network utilities on the POA Management Node to check if POA can connect to ports 4433/4434 on the PVC server:
# nmap -P0 <PVC_SERVER> -p 4433,4434 # telnet <PVC_SERVER> 4433 # netcat <PVC_SERVER>:4433 # openssl s_client -connect <PVC_SERVER>:4434 -cipher ADH-AES256-SHA
<PVC_SERVER>in the commands above with the IP address or hostname of the PVC server in question.
Check/configure firewall rules on the PVC server in accordance with the Parallels Knowledgebase articles: