Re: using parallel for remote host processing

[Ole Tange]

 On Fri, Oct 11, 2013 at 10:33 PM, Maracic, Jay
<Jay.Maracic@morganstanley.com> wrote:

> So what I want is to be able to pass the following ssh options into
> parallel:
>
> -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null
:
> I have modified parallel to include the options, and this works as desired.

I am surprised that you have been able to change the code, but you
have not been able to see how to do it without changing the code.

I am not sure if that means that the documentation is hard to
understand or that the code is easy to understand.

> sub sshcommand_of_sshlogin {
>     # 'server' -> ('ssh -S /tmp/parallel-ssh-RANDOM/host-','server')
>     # 'user@server' -> ('ssh','user@server')
>     # 'myssh user@server' -> ('myssh','user@server')

!!!!!!!!!!!!
>     # 'myssh -l user server' -> ('myssh -l user','server')
>
>     # '/usr/bin/myssh -l user server' -> ('/usr/bin/myssh -l user','server')
!!!!!!!!!!!!!!

Note those 2 comments: They actually give you hints on how to do it.

> I am wondering if parallel can accept these ssh options thus obviating the
> need for modifying parallel?

Also look at 'man parallel':

      -S [ncpu/]sshlogin[,[ncpu/]sshlogin[,...]]
       --sshlogin [ncpu/]sshlogin[,[ncpu/]sshlogin[,...]]
:
                An sshlogin is of the form:

                  [sshcommand [options]][username@]hostname
:
                For examples: see --sshloginfile.
:
       --sshloginfile filename
       --slf filename
                File with sshlogins. The file consists of sshlogins on
separate lines.
                Empty lines and lines starting with '#' are ignored. Example:

                  server.example.com
                  username@server2.example.com
                  8/my-8-core-server.example.com
                  2/my_other_username@my-dualcore.example.net
                  # This server has SSH running on port 2222
                  ssh -p 2222 server.example.net
                  4/ssh -p 2222 quadserver.example.net
                  # Use a different ssh program
                  myssh -p 2222 -l myusername hexacpu.example.net
                  # Use a different ssh program with default number of cores
                  //usr/local/bin/myssh -p 2222 -l myusername
hexacpu.example.net
                  # Use a different ssh program with 6 cores
                  6//usr/local/bin/myssh -p 2222 -l myusername
hexacpu.example.net
                  # Assume 16 cores on the local computer
                  16/:

Please let me know how I can improve the documentation so you would
have found this.

/Ole