Question

I’m trying to do something like this, I need to take backup from 4 blades, and
all should be stored under the /home/backup/esa location, which contains 4
directories with the name of the nodes (like sc-1, sc-2, pl-1, pl-2). Each
directory should contain respective node’s backup information.

But I see that “from which node I execute the command, only that data is being
copied to all 4 directories”. any idea why this happens? My script is like this:

for node in $(grep "^node" /cluster/etc/cluster.conf | awk '{print $4}');
do echo "Creating backup fornode ${node}";
ssh $node source /etc/profile.d/bkUp.sh;
asBackup -b /home/backup/esa/${node};
done

Answer 1

Your problem is this piece of the code:

ssh $node source /etc/profile.d/bkUp.sh;
asBackup -b /home/backup/esa/${node};

It does:

1. Create a remote shell on $node
2. Execute the command source /etc/profile.d/bkUp.sh in the remote shell
3. Close the remote shell and forget about anything done in that shell!!
4. Run asBackup on the local host.

This is not what you want. Change it to:

ssh "$node" "source /etc/profile.d/bkUp.sh; asBackup -b '/home/backup/esa/${node}'"

This does:

1. Create a remote shell on $node
2. Execute the command(s) source /etc/profile.d/bkUp.sh; asBackup -b '/home/backup/esa/${node}' on the remote host

Make sure that /home/backup/esa/${node} is a NFS mount (otherwise, the files will only be backed up in a directory on the remote host).

Note that /etc/profile is a very bad place for backup scripts (or their config). Consider moving the setup/config to /home/backup/esa which is (or should be) shared between all nodes of the cluster, so changing it in one place updates it everywhere at once.

Also note the usage of quotes: The single and double quotes make sure that spaces in the variable node won’t cause unexpected problems. Sure, it’s very unlikely that there will be spaces in “$node” but if there are, the error message will mislead you.

So always quote properly.