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sets up an encrypted port forward from the external machine (where ssh runs), port 8000 to port 9000 on cpu-b12-xyz.

Use '-t'

When you run a remote command via ssh as in

bash$ ssh cpu-b12-xyz lengthy_command

then it is important to know that 'lengthy_command' is not associated with any (remote!) terminal.  This means that when you kill ssh on your local machine (Ctrl-C) then the remote command will keep executing (the remote command is not a child of the local 'ssh' and cannot be notified of its death). The '-t' option forces the remote ssh server to allocate a pseudo-terminal and associates the lengthy_command process with that terminal and this will allow propagation of signals:

bash$ ssh -tt cpu-b12-xyz lengthy_command

If you kill this ssh on your local machine then it will cause the lengthy_command to receive a signal (via its controlling terminal) and terminate as well. Multiple 't's ensure a remote terminal is allocated even if there is no local terminal (e.g., if the ssh command is called from a daemonized script).

screen is Your Friend!

When you run an interactive session from remote then this often carries a lot of context information (environment, running processes etc.). It can be very painful if you get disconnected and as a consequence lose all of this context and have long-running build processes killed. Use the 'screen' utility. If you work on AFS then screen also keeps your tokens alive for you (until they expire, of course) - provided that you run a pagsh:

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