Grid Setup (without Globus Toolkit)
The grid system on the cluster uses either the EaStCHEM PaSS software or Globus Toolkit and UK eScience certificates. If you want to use Globus Toolkit (the preferred method) then please see the how to set up grid access (with Globus Toolkit).
The EaStCHEM PaSS software is based on the use of the secure shell (SSH) it must be set up for password-less access before you can use the grid system.
You may also want to look at the EaStCHEM PaSS User Guide.
SSH Setup
As mentioned above, PaSS is based on having password-less access between the local and remote hosts. To allow this you must generate a public-private key pair for any hosts that you wish to submit jobs from and transfer the public key to the remote host you want to submit jobs to. This has to work in both directions so you will need to perform the steps below on both hosts that you would like to use together in the grid.
The first step is to generate a public-private key pair for the local host. On the local host:
my_user@local> ssh-keygen -t rsa
You should accept all the defaults at any questions (i.e. just press return without entering anything). The pass phrase can be left blank if you wish.
You must now check that the public part of the key contains the fully qualified domain name (FQDN) of the local host. List the contents of the public key:
my_user@local> cat .ssh/id_rsa.pub ssh-rsa <some long string of letters and numbers> = my_user@local.host.com
If you see output like that above with the FQDN (local.host.com) instead of just the local name (local) then you are OK and can skip on to the transfer step. If not, you need to go in and edit the file to include the FQDN (you can get this from hostname -f).
Now you need to transfer the public key to the remote host. You can do this any way you like. Here, I am using scp:
my_user@local> scp .ssh/id_rsa.pub me@remote.host.com:.ssh/id_rsa.local
(You will need your password on remote.host.com for this step.) Finally, you need to transfer the contents of the public key to the authorized hosts file so the remote host knows to trust a connection from the local host. You can log in to the remote host to do this but I am going to use ssh from the local host (again, I will need my password for remote.host.com):
my_user@local> ssh me@remote.host.com 'cat .ssh/id_rsa.local >> .ssh/authorized_keys'
Now you should not need your password for remote.host.com. You can test this by issuing the following command:
my_user@local> ssh me@remote.host.com 'hostname -f'
This should not ask you for a password and should return the hostname of the remote machine.
Now you should log into remote.host.com and repeat the above process for transfers in the reverse direction.
The final step is to create a directory on remote.host.com where the files for grid jobs will be temporarily stored (called remote_jobs. Here, I do this using ssh from local.host.com
my_user@local> ssh me@remote.host.com 'mkdir remote_jobs'
Congratulations, you are now ready to use the grid!