Monday, August 17, 2009

Poor Man's Cluster - Step 8

Poor Man's Cluster
Topic: LinuxClusters

Now that I think about it, the title of this thread should not have been "Poor Man's Cluster" as the only thing cheap about it is the firmware and software which is free, but the hardware is state-of-the-art.  The topic should be something like: "Instant Cluster, Just add water!" 
Anyway, just to emphasize the public key ssh athentication, here is the thread from that I linked below:
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My students and I are interested in setting up a parallel java (PJ) cluster ( These are my advanced independent study students who just spent a year working with MPI & OpenMosix using C & C++. MPI is getting a bit dated and the OpenMosix project just closed, so they want experience with a new kind of cluster/grid paradigm.

Anyway, we've complied with all the installation requirements for PJ ( middle of page) except for the following:

Furthermore, it must be possible to do an SSH remote login from the frontend processor to each backend processor without the user having to type a password. This is done using public key authentication. SSH must have public key authentication enabled. Each user must set up SSH public and private keys in his or her account. For further information, refer to the SSH documentation.

I have sshd running, but I don't have any experience with "public key authentication." Anyone out there have any suggestions or tips for this?

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OK, I figured it out. I simply started sshd and created a login on each PC with the same userid and passwd. I logged into each and issued the following commandline:

ssh-keygen -t rsa

This created a file called in the hidden .ssh folder of each user's home dir. Then I scp'ed these files to each machine (with diff filenames) to cut and past one large file calledauthorized_keys2 and that's it! I can now ssh to and from each PC using that userid and no passwd. In fact, as I was logged into each PC with the same userid, I don't think I even need the userid to ssh or fish!


HTH Some1,
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Correct, instead of fish:// in konqueror with a passwd, I can fish without a passwd.

Also, I can simply 
fish:// - no need for a userid or passwd as long as I'm using the same userid on each PC.

You just have to have the one userid in common on all PCs, sshd running and the correct authorized_keys2 file on each home dir. Just log into one with a passwd normally, then fish or ssh away to your heart's content without userids or passwds!

HTH Some1 even though my application may be a bit unusual,

PS: any1 else out there setting up linux clusters?
Hope that helps,

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