Scriblings Of A GEEK

SSH Continued

Coming back to what we left yesterday night was utilizing the the ssh agent to push updated file like /etc/resolv.conf or /etc/ntp.conf across a list of servers.

Its much better than logging into each server and modifying them .

Say i have a list of 100 servers in a file called /home/nitin/list.

#more /home/nitin/list
server1.mydomain.com

server3.mydomain.com

server4.mydomain.com

and so on till server 100 server name.

Here is a simple script which would replace the existing /etc/ntp.conf with the file i updated as /home/nitin/ntp.conf

I am assuming that you have your rsa or dsa key on all the 100 servers and also you are comfortable with using the ssh-agent utility.

Last but not the least you know the scp utility and also have superuser privilidges on the machines you want to replace the file on.;

The script reads as :

#for i in `cat list` ;do scp /home/nitin/ntp.conf nitin@$i:/etc/ntp.conf; done

Thats it no manual intervention needed and also just run the script watch the fun.

Another stuff you can do is if u want to run certain commands like check disk usage for all servers what you can do is :

#for i in `cat list` ;do ssh nitin@$i df -h; done

The other very good utility is rsync : http://rsync.samba.org/

This is how you do it :

#rsync -a -e ssh /home/nitin/ntp.conf nitin@remotemachine.com:/etc/ntp.conf

Here it is important to use the -e ssh so that rsync uses the ssh portocol to sync files rather than rcp.

I guess that makes life a lot more easy for sysad's handling more than 500 servers and needing to push stuff.

If some one's got a better method pls put it here would help a lot of us.

adiew

Nitin :)

posted by Nitin @ 8/29/2004 01:06:00 AM