Multiplexing of connections

[tdaff]

Original report by Tom Daff (Bitbucket: tdaff, GitHub: tdaff).

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@rainwoodman mentioned in issue #12 that SSH multiplexing or a SOCKS proxy could be used to consolidate connections. This could be useful, especially to avoid passwords, but still considering whether it should be something managed by the kernels, or just well documented.

[tdaff]

Original comment by Tom Daff (Bitbucket: tdaff, GitHub: tdaff).

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At the moment (version 0.4.4) the kernel will not multiplex, even if there is a multiplex available. I think the main issue would be managing the master. If things are not set up correctly then if a kernel kills the master then every other ssh connection will hang. Since the kernels don't know about each other or system processes, maybe this is best left to be configured by the user at a system level...

To enable multiplexing in the current version, first delete al occurrences of ``-S none` in kernel.py, then enable multiplexing for the host in ~/.ssh/config:

Host myhost.ac.uk
    ControlMaster auto
    ControlPath ~/.ssh/%r@%h:%p
    ControlPersist 1

This should create a master that remains in the background when needed and multiplex everything through that.

[tdaff]

Original comment by Dejan Pavlic (Bitbucket: dejop, ).

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I can confirm that getting rid of -S none allows ControlMaster to work; this also has an added benefit of enabling people like me, who are stuck behind 2FA, to use remote_ikernel. Very good.

[tdaff]

Original comment by Tom Daff (Bitbucket: tdaff, GitHub: tdaff).

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Documented in README