VNC console does not work in SolusIO: Connection failed: Unexpected response code: 502

Symptoms

• VNC console does not work in SolusIO:

  CONFIG_TEXT: Connection failed

• The following error is displayed in Dev Tool of a browser:

  CONFIG_TEXT: WebSocket connection to 'wss://example.com/vnc?url=203.0.113.2:7778/3fcfc36a-72ee-4512-9e97-85e5c753873f' failed: Error during WebSocket handshake: Unexpected response code: 502

• CentOS 8 is used for Compute Resource.

Cause

Attempt to establish a connection on port 7778 from Management node to Compute Resource with telnet fails:

# telnet 203.0.113.2 7778
Trying 203.0.113.2...
telnet: Unable to connect to remote host: No route to host

due to the fact that port 7778 is not added in firewalld rules.

Resolution

1. Access affected compute resource via SSH.

2. Add port 7778 to firewalld:

   # firewall-cmd --zone=public --add-port=7778/tcp