Home / server / Questions / 359309
Accepted
Eytan
Asked: 2012-02-13 07:41:14 +0800 CST

ssh + multiple ssh connection failed

  • 772

I have 47 Linux client machines and one Solaris server machine (all Linux client machines are red-hat 5.1)

all clients perform ssh connection to the server in order to verify if /tmp/generic_error.txt exist in the server

clients do the ssh exactly on 12:00 PM

I see something strange

Some of clients not recognized that /tmp/generic_error.txt exist in the server in spite this file was exist

So my first conclusion is that I can't perform multiple ssh from 47 machine to one server ?

But I don’t sure if I right ?

Please advice what the best process to perform ssh from 47 Linux clients to one server exactly on the same time?

remark - I can’t touch and configure the "ssh key-based authentication" because the Lenox’s machines must have password (part of our security policy)

  • example of the expect script in the linux's clients - this expect verify if /tmp/generic_error.txt exists in the server (this action should be performed exactly on 12:00 PM on all 47 linux clients)

10.10.18.61 - server machine

 expect=`cat << EOF

 set timeout -1
 spawn  ssh  10.10.18.61
       expect {
                 ")?"   { send "yes\r"  ; exp_continue  }

                 word:  {send freenelsonmandela\r}
              }
 expect >  {send "ls /tmp/generic_error.txt\r"}
 expect >    {send exit\r}
 expect eof
 EOF`

exe expect:

expect -c  "$expect"  | grep "generic_error.txt"  | grep -v ls
linux ssh port shell-scripting expect

1 Answers

  1. Best Answer

    If i understand correctly, you have 47 clients that need to know if some file exists on serverhost. And this needs to be run all at the same time.

    Lets start with the smallest component, your file test. You can expand this some

    This should work with most shells

    ls /tmp/file 2>&1 >/dev/null && echo Found || echo Not Found

    Or BASH

    [ -f /tmp/file ] && echo Found || echo Not Found

    You may want to check around more for the shell you are using, likely ksh, and double check its builtins for checking to see if a file is present.

    Now slightly outwards, at the end of your expect, you are not doing anything with the results. this is likely the cause of most of your issue. you can access $expect_out(buffer) which will contain what ever was between the last matches.

    typically this is used as:

    puts "$expect_out(buffer)"
    • 0