Running script on remote server

Shell Programming and Scripting
1

Hi All,

I need to run a ksh script on around 200 servers(consisting of AIX,LInux,HP-UX,Solaris). The script is there in the /tmp directory of all the servers. I want want to execute the script in background on the respective servers and then exit from there. I have written something like below:

 
for i in `cat Server_List`
do ssh -q $i "nohup ksh /tmp/script.ksh -E &"
done

But i want the for loop to execute the remote script and then exit and proceed to the next server in Server_List.

For this i wrote:

 
for i in `cat Server_List`;
do ssh -q $i < "ksh /tmp/script.ksh -E &; exit";
done

But i am getting errors like below:
bash: ksh /tmp/script.ksh -E &; exit: No such file or directory
bash: ksh /tmp/script.ksh -E &; exit: No such file or directory
.... .... ..... ..... ...... ......

Can someone help me in creating a script that serves my objective.

2

Hi, in this moment I can't test this code, but try this way:

for i in `cat Server_List`
do 
	ssh -l login_name -q $i "nohup /tmp/script.ksh -E" &
done
3

That is a useless use of cat and dangerous use of backticks.

while read SERVER
do
        ssh -q -l login_name $SERVER 'nohup ksh /tmp/script.ksh -E' &
done < serverfile

# Wait for all of them to finish
wait
4

Try

ssh -qxn $i "ksh -c 'exec ksh /tmp/script.ksh >/dev/null 2>&1' &"
sleep 1

The -x closes X11 connection.
The -n closes stdin; stdout and stderr is closed at the remote side.
The ksh -c wrapper is to ensure that >/dev/null 2>&1 works even if login shell were a C-Shell.
The sleep 1 is best practice (allows to ^C interrupt, avoids problem with too fast socket allocation, ...)
I think nohup is not needed here.
-E option is not portable - specific to Linux/pdksh?

5

@MadeInGermany

-E option is needed as an argument for this script. Also,since i will be running the script over ssh is the "-x" option needed?

---------- Post updated at 12:21 PM ---------- Previous update was at 12:19 PM ----------

@Corona688

SERVER is the Serverlist file is guess, then what is "serverfile"?

6

SERVER is the name of the variable to read into, which is why $SERVER is used later.

serverlist is the server list file.

I'd actually make one change here:

ssh -n -q -l login_name $SERVER 'nohup ksh /tmp/script.ksh -E' &
7

Also, i want to invoke the script in background on the respective servers and then exit from there and then proceed to the next server on the list, i dont want the script to wait for finishing on one server and then proceed to the next.

8

My script does that. It doesn't run them in turn, it runs them in parallel.

It waits for all of them at once, afterwards.

9

My bad - then it's

ssh -qxn $i "ksh -c 'exec ksh /tmp/script.ksh -E >/dev/null 2>&1' &"
sleep 1

Without -x the remote side wants to connect to the calling host's X11 display. If it succeeds it will block ssh until it exits.

---------- Post updated at 12:41 PM ---------- Previous update was at 12:36 PM ----------

You can as well try

ssh -qxn $i "ksh -c 'exec ksh /tmp/script.ksh -E >/dev/null 2>&1'" &
sleep 1

This will be faster if a remote server is down.

---------- Post updated at 12:51 PM ---------- Previous update was at 12:41 PM ----------

@Corona688:
The following descriptor magic allows ssh without -n

while read SERVER <&3; do
 ssh ... # -n not needed
done 3< Server_List