Shell Programming and Scripting

We have 15 servers. Hostnames for these 15 servers are stored in a text files and loop through each server to connect to the remote server and run a command, but this loop process runs the command one after another. However, the requirement is to run the same command on all 15 servers at the same time. We are connecting the remote servers using public/private key files.

Code:

textfile="/home/laknar/hostfile"

while read r
do
	ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no laknar@$r 'run a shell script'

done < $textfile

Any idea would be great.

putting the whole 'ssh' in the background (&)?

That depends heavily on how you define "same time". If in above you run the remote command in background, you'll achieve a start of all scripts within a few seconds, as each ssh returns immediately after submitting the respective script. If that is not acceptable, you might consider using a cron job on each server, having synchronized the servers' clocks meticulously. But this would still carry a few seconds risk...

Code:

textfile="/home/laknar/hostfile"

while read r
do
	ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no laknar@$r 'myscript.ksh &'

done < $textfile

is this correct?

Why not giving it a shot and reporting back the results?

I'd suggest not, but more of a concern, how do you handle a server not being available for some reason?



Robin

Hi All,

Any one can tell me how to avoid passphrase or is there any way to login to multiple servers and run one command with out looking for passphrase

Thanks,