Problem: During upgrade from UCS 4.2 to 4.3 server looses network connectivity
When performing the upgrade through ssh with univention-upgrade --ignoressh you are loosing network connectivity. The host does not reply to ping command. You can log on through the local console and notice the network is down.
Environment
The server has multiple network interfaces configured as bonding device.
Solution
Workaround #1
Restart the server with the reboot command and continue with the upgrade process as before.
Workaround #2
Start the upgrade through a remote console (ie iLO or VMware RemoteConsole)
Workaround #3
Start the upgrade procedure through a screen or tmux session.
Note: When using the switch --ignoressh you perform the upgrade procedure by ignoring the warnings about the possibility of loosing network during upgrade process and therefore loss of network is to be expected.