On Thu, May 11, 2017 at 6:24 PM, Ole Tange <[email protected]> wrote: > On Mon, May 8, 2017 at 10:20 PM, Joe Sapp <[email protected]> wrote: >> On Mon, May 8, 2017 at 4:09 PM, Ole Tange <[email protected]> wrote: >>> On Mon, May 8, 2017 at 9:02 PM, Joe Sapp <[email protected]> wrote: > : >> I am using --controlmaster in my calls to parallel, but it seems to >> still be making new connections even though I don't have a custom ssh >> command. I will try to come up with a test case and some evidence. > > GNU Parallel starts a 'ssh -MTS socket' which is kept open for the whole time:
Oh okay, this makes sense now. I just did some testing after reading the ssh ControlMaster section a bit closer and opening up a master ssh session to $SERVER: seq 5 | parallel --sshlogin $SERVER --ssh "ssh -v" echo The output showed the following after each echo, indicating that it used multiplexing: debug1: mux_client_request_session: master session id: 2 The problem was twofold: I had enabled ssh ControlMaster globally, so all of my ssh sessions were creating new master sessions. Once that was resolved, I could see that using the "--controlmaster" option of GNU Parallel was creating a new master session as well (as you point out). If I just omit the option it will re-use my existing master session as expected. -- Thanks, Joe
