Cluster like SSH client with hop definition capability

[sirbijan]

Hello

I work in a huge farm of servers (to me at least!) where I have up to 60 servers in one of my branches to connect to. You can not directly see these 60 servers, you have to login into a jump/hop server first and from that machine, you can see the 60 nodes to login to.

Because these nodes are the same, I installed Cluster SSH in the jump server, then I have to "ssh -X" into the jump server and then open terminal for all of them at once.

I was wondering if we have any kind of Cluster SSH like app that one can define a jump server (or even multiple jump servers) for. This way I didn't have to install anything on my jump machine.

Cheers,

[Irithori]

One of my datacenters has a similar setup.
And even worse, I dont even have ssh, but only a http(s) proxy.
Sad story, donīt ask

Anyway, I do use "corkscrew" as a proxycomand to access these boxes, and it works stable.

For ssh, you need a slightly different approach, namely netcat.

I just googled the proxycommand, not actually tested it.
But it should get you started.

The rest of the .ssh/config snippet should be ok (copied and sanitized from my own)


- You need netcat on the gateway box, and in the $PATH of the connecting user.
"netcat" is "nc" on some distributions.
- authorized key setup helps a lot
- so does ssh-agent


On your client machine:

mkdir -p ~/.ssh/control-master

Then edit ~/.ssh/config
host *.<BRANCH_DOMAIN>
  ControlMaster auto
  ControlPath ~/.ssh/control-master/%r@%h:%p
  ProxyCommand ssh -e none <BRANCH_GATEWAY> exec netcat -w 30 %h %p

host <BRANCH_NETWORK>    # e.g.: 10.56.100.*
  ControlMaster auto
  ControlPath ~/.ssh/control-master/%r@%h:%p
  ProxyCommand ssh -e none <BRANCH_GATEWAY> exec netcat -w 30 %h %p

host *
  ServerAliveInterval   10
  ForwardAgent          yes

Test if you can reach the branch machines with ssh by either
ssh <HOST>.<BRANCH_DOMAIN>
or
ssh <BRANCH_IP>

Once ssh works, clusterssh and parallel ssh should work as well.

Have fun


P.S.:
ControlPath and ControlMaster will multiplex ssh connections through the first established one.
Means: You should see only one connection from your client machine to the branch gateway, even if you parallel-ssh into all 60 machines.