Deploying Cronjob to multiple servers

Shell Programming and Scripting
1

I figure that this is a shell scripting issue so I'll post here.

I'm attempting to deploy a cronjob to a variety of servers, some 200-odd, of all walks of life. Mostly AIX, but some Solaris, some HP-UX, some Linux (of varying distributions), etc. I initially thought about utilizing a mass deployment with a scripted rsh or ssh command, echoing in an appended line that contained the cronjob and executing a refresh/restart of the cron service. But that won't work, so I'm stuck with another method, utilizing a vi command. This is supposed to be doable but I'm having some trouble visualizing it. If someone could get me started in the right path that would be great, or provide a script that they've used in the past.

Secondly, if simply echoing/inline editing crontab entries won't work, what will I need to do if I need to edit the file after the initial deployment and adjust the entry for whatever reason (syntax error, change the execution time/date, etc.)? A friend of mine suggested using a perl script that invokes a vi-style search-and-replace function but will these changes be seen by cron on these systems or not? If not, is there another method recommended?

2

Create an ed script, call it mycron:

1a * * * * * /path/to/myscript > /tmp/logfile 2&>1
.

/var/spool/cron/crontabs is the directory for Solaris crontabs. You will need an OS-specific variant of the script below.

This script assumes you are able to write the crontab, and that you have ssh keys installed. It also makes a lot of assumptions about your boxes - ie all of the solaris boxes have the same usernames, permissions, etc.

#!/bin/ksh
#ip.dat is a list of nodes of one flavor of OS
while read nname
do
sftp $nname <<EOF
   put mycron
   exit
EOF
ssh $nname '(cat mycron %&& echo "w" ) | ed - /var/spool/crontabs/someusername'

vi is based on ed. ed will not break your crontabs. Do not put too much faith in my example ed script, test it first.

3

Thank you for the reply.

It doesn't quite answer my original question. The big one: will any changes done to the crontab file manually (through ed/vi/echoing text in/etc.) cause cron to see those changes? I've been told by our SME that they won't, at least not in Solaris. What about other OSes, like AIX, Tru64 or Linux?