Re: SSH Connection Multiplexing (Sharing)?

[Peter Dimitrios <pe...@gmail.com>]

 At one point I made some notes about how using SSH multiplexing could
sometimes cause errors ("ControlSocket already exists") in some
situations, and recovering from it required some work (forcing the
multiplexed socket closed via ssh -O stop and retrying usually
worked).   It also required managing the parent connection process.
So I think the decision was made to avoid using it to make VCL scripts
more reliable in the face of varied Linux distributions in use.

  Starting with OpenSSH 5.6, the ControlPersist keyword was defined to
let SSH handle creating the parent process and killing it after a
defined period of inactivity.  However, I don't think that was in wide
deployment in most distros at the time.  Perhaps some more testing
with current distros could be done to see if it works well now?    I
use it on my dev VCL servers and images and usually have no troubles
(mostly because I can easily see if  it goes awry and kick it :-) ).

  BTW, a nice writeup on using all the SSH multiplexing /
ControlMaster features is at
http://en.wikibooks.org/wiki/OpenSSH/Cookbook/Multiplexing

  -Peter Dimitrios  - PeteDaGuru@gmail.com

On Fri, Dec 20, 2013 at 11:21 AM, Dmitri Chebotarov <dc...@gmu.edu> wrote:
> Hi
>
> Would it make sense to enable SSH multiplexing (sharing) in VCL env?
>
> There are many SSH commands executed during reservation and image capture
> and in a large environments sharing SSH connections could/should improve
> reservation times and performance.
>
> The vcld would execute 'ssh <worker> sleep Xm &¹ as 1st command and the
> rest of SSH communications with this VM will be done thru the established
> session (ZF-1).
>
> On VCLD¹s /root/.ssh/config:
>
> ControlMaster auto
> ControlPath /root/.ssh/tmp/%h_%p_%r
>
>
>
> --
> Thank you,
>
> Dmitri Chebotarov
> VCL Sys Eng, Engineering & Architectural Support, TSD - Ent Servers &
> Messaging
> 223 Aquia Building, Ffx, MSN: 1B5
> Phone: (703) 993-6175 | Fax: (703) 993-3404
>
>
>
>
>