Everyone and his dog has their multihost ssh so why not me?

2009-08-28 by mjr

I call this sshtomany:

#!/bin/bash

cmd="$*"
cmd="${cmd/#* . /}"
[ "$cmd" = "$*" ] && echo "Usage: $0 [HOSTS] . [COMMAND]" && exit 127

while [ "$1" != . ] && ssh $1 -vt $cmd ; do
  echo Success at "$1"
  shift
done

clusterssh and its emacs equivalent are quite handy if you want to execute commands simultaneously and fairly graphically.

The various versions of dsh and dssh are flexible command-line tools.

But sshtomany will do 90% of simple jobs by running the same ssh command on a list of hosts, one after another.

This entry was posted in GNU/Linux and tagged bash, clusterssh, dsh, shell script, ssh. Bookmark the permalink.

4 Responses to Everyone and his dog has their multihost ssh so why not me?

AH says:

2009-08-28 at 07:29

What’s wrong with func?

https://fedorahosted.org/func/
Noufal Ibrahim says:

2009-08-28 at 10:45

Sort of related, take a look at http://www.netfort.gr.jp/~dancer/software/dsh.html.en
Jeff Schroeder says:

2009-08-29 at 22:46

Try out Ticketmaster’s gplv3 “onall”. There isn’t much better if you want to run a command on say… 400 or more hosts.

https://code.ticketmaster.com/trac/browser/onall/trunk/onall

An easy example would be:
host -l linux.yourdomain.com internal.dns.server.that.lets.you.axfr | awk ‘^spare/{print $1}’ > list-of-lots-of-servers.txt
onall -f list-of-lots-of-servers.txt “uname -r”

grep -v ‘lax’ list-of-lots-of-servers.txt | onall “ps -efH | grep badguy”

The biggest advantage this has over

for i in $(cat servers.txt); do
ssh ….
done

is mainly that it will connect out to hosts asynchronously in batches of 20 at a time (configurable) and return the results to you as they come in. Real good stuff.
MJ Ray says:

2009-09-02 at 17:21

What’s wrong with func seems to be that it supports only fedora (it says), it’s another subsystem to maintain and it seems to require writing modules before I can start using it for new tasks, but maybe I don’t understand it.

I didn’t see onall before. I don’t think it does serial interactive invocation, which is useful for my group of slightly awkward hosts – note the -t option I use for ssh. Also, can you understand batches of results at a time? Examples of the output would be interesting.

As mentioned, I looked at dsh. I didn’t use it because not all of my workstations run debian. I followed the link to dsh 2.0 and found what I thought was a dead project. Again, I’m not sure about serial interactive invocation.