scripting hosts file rollout

[themoog]

I need a little help with scripting...

I want to rollout a master hosts file to a number of machines, the only thing is that /etc/hosts file on each machine is slightly different, ie the 5th line will have:
<host ip> <hostname> loghost

Can someone recommend a script that will keep the first 5 lines and append the master hostlist to the end of the /etc/hosts file ?

I guess awk should be used, however I've just started to learn it so am in need of some advice.

Cheers,
themoog

 

[esserc]

Most people I know of have gone away from the concept of a 'master host file'. Or of using a host file for anything other that local interfaces for that matter. Thats why the internet gods gave us wonderful tools like DNS, LDAP, and NIS (although NIS+ is actually a tool of the devil).

But if you insist on doing it anyway....

Do something like this:

#!/usr/bin/ksh
head -5 /etc/hosts > /tmp/hosts.tmp
cat newhosts >> /tmp/hosts.tmp
mv /tmp/hosts.tmp /etc/hosts

 

[themoog]

Cheers esserc.

yeah we are about to start using LDAP soon, but in the meantime have to stick with silly hosts files.

I should have remembered the head command and >>'s (doh)

whats the fastest way to roll this out now ? ftp to each box and run, or is there a way to script a secure copy and secure rsh ? to do it securely and automatically to all boxes at once ?

Thanks again
themoog

 

[esserc]

The best way might be to make the script to do the work and the master host file then send them both out to /tmp using rdist then use rsh to kick off the scripts.

Or you could do this:
---
#!/usr/bin/ksh
for host in `cat hosts.todo`
do
rsh ${host} &quot;head -5 /etc/inet/hosts&quot; > /tmp/hosts.tmp
cat newhosts >> /tmp/hosts.tmp
rsh ${host} &quot;chmod 644 /etc/inet/hosts&quot;
rcp /tmp/hosts.tmp ${host}:/etc/inet/hosts
rsh ${host} &quot;chmod 444 /etc/inet/hosts&quot;
done
rm /tmp/hosts.tmp

---
hosts.todo is a list of hosts to send the file to.

Also, remember that this needs to run as root with a .rhost file.

And, please test this before using it. I just wrote it off the top of my head and I'm not sure if I got rcp right.

Good luck.