mjhjmtu

I have 4 suse server working as cluster. name CS-1 CS-2 CS-3 CS-4

On CS-1 can ssh to CS-2 CS-3 CS-4 directly (ssh CS-2, ssh CS-3, ssh CS-4)
On CS-2 can ssh to CS-1 CS-3 CS-4 directly (ssh CS-1, ssh CS-3, ssh CS-4)

I have 3 commands need to execute on all of these 4 servers

sed 's/aes128-ctr/aes129-ctr/' </etc/ssh/sshd_config> sshd_config.new; mv sshd_config.new sshd_config
sed 's/aes130-ctr/aes131-ctr/' </etc/ssh/sshd_config> sshd_config.new; mv sshd_config.new sshd_config
sed 's/aes132-ctr/aes133-ctr/' </etc/ssh/sshd_config> sshd_config.new; mv sshd_config.new sshd_config

how to do this in one shell script?

There are several ways to do this sort of thing.

If this is the sort of thing you're likely to be doing a lot, you might want to look into Ansible or other similar automation tooling.

If this is a one-off, probably the most straightforward way is to copy those commands into a script, scp the script to the remote machines, and then remotely execute them with ssh:

$ for host in cs-2..4; do scp my-script.sh myuser@"$host":; ssh -t $host "sudo ./my-script.sh"; done

As an aside, if you are confident in your sed command, rather than manually writing to a temp file and copying the new one in place, you can do something such as:

sed --in-place 's/aes128-ctr/aes129-ctr/;s/aes130-ctr/aes131-ctr/;s/aes132-ctr/aes133-ctr/' /etc/ssh/sshd_config

As this is one command, you can then simply for each host:

$ ssh user@host "sed --in-place 's/aes128-ctr/aes129-ctr/;s/aes130-ctr/aes131-ctr/;s/aes132-ctr/aes133-ctr/' /etc/ssh/sshd_config"

If you have to run same commands on some set of servers quite often, I would recommend to look into pssh tool and related tools from the same package.

What I've done on my laptop, from where I need to control ~50 remote hosts (with ssh set up use key authentication already):

1. create list of hostnames like ~/.dev-hosts.list. This one will just have your list of hostnames

dev-host1
dev-host2
...

2. Use following command to run date on each host from that list:

pssh -h ~/.dev-hosts.list -l developer -i date

3. 
   Optional: wrap it all in an alias for convenience: alias run.on.dev='pssh -h ~/.dev-hosts.list -l username'. After that to run date on these machines and get output you are just few keystrokes away:

run.on.dev -i date

Obviously, you can execute this way practically any command, including your sed cases.

Note that -l allows you to specify username to ssh to these hosts, and -i allows you to see the output your command produces.