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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 ...
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  1. #1
    Just Joined!
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    Cool Cluster like SSH client with hop definition capability


    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,

  2. #2
    Trusted Penguin Irithori's Avatar
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    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:
    Code:
    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.
    Last edited by Irithori; 03-22-2011 at 04:10 PM.
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