kishorebhargava

While the country was gearing up to celebrate the 61st Independence Day, I had a sheer dependence on technology. I was helping a client migrate their mail server, (it had to be shifted from one data centre to another) which was taking a little longer than usual. I finally landed up staying up almost till 0400 hrs. Not that its unusual, but I do like to get to bed before dawn.

Anyways, while waiting for some things to happen, I kept wondering if there was an easier way to manage the three servers in question. In particular, I needed an easy way to type the same command on all three machines at the same time. They are identical servers, just that they are in three different locations. Google to the rescue and a few minutes later I was installing ClusterSSH on my notebook. Now that I have seen and used it, I really wonder how I’ve survived all these years without it.

As the name suggests, its essentially meant for cluster administration, where the need for issuing the same command on all nodes is a very common requirement. The good thing is that its not limited to clusters. If you add a bunch of hosts either on the command line or in the config files, fire up cssh and you get a separate Xterm for each host you add, except that you also get a little box in which whatever you type is echoed on all the terminals. Just what the doctor ordered. Very nifty indeed.

I was then able to check the mail queues, configure the SMTP servers, restart the mail services, all from one place simultaneously on all three servers. A real time saver.

So what kept me up till 0330 hrs, was one of the servers not clearing its queue. Once everything was working, I just couldn’t enough of ClusterSSH and stayed up playing with it till Jyoti came in search for me and dragged me away from it.

With that as a start of the Independence day for me, I finally got some rest, but clearly not enough. I was woken up at 0830 hrs to fix yet another mail server. Why, oh why do these servers have to misbehave on a National holiday. The issue turned out to be minor and got solved rapidly. Now to actually get back to holidaying.

Kabir wanted to fly some kites so we went out in search for some kite flying experts. Jyoti’s brother Navin is quite an ustaad at it and with his help we managed to get three of our kites up and rather high at that. Some of the kids from a neighbouring village watched in amusement as we tried to get some more kites up and finally came to our rescue.

We ended the day with a long awaited annoucement - FOSS.IN/2008 dates and venue. November 25-29, 2008 at the National Science Symposium Centre, Indian Institute of Science, Bangalore, India.

Hope you had a good Independence day too!

Cheers…Kishore
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PS: Some important info on ClusterSSH that I left out:

I use Fedora 9 on my laptop and found ClusterSSH in the repositories, a simple “sudo yum install clusterssh” worked great for me.

Use cssh -u > $HOME/.csshrc to create your default config file.

Adding the cluster and server tags to .csshrc did not work for me, I finally used /etc/clusters for that, the syntax is simple:

clusters = myboxen

myboxen = username@hostname1:port username@hostname2:port

It helps to have your SSH keys already copied on the target hosts.