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best way to check amazon ec2 instance's availability

list Jeremy Laidman
Sat, 2 Nov 2013 02:14:59 +1100
Message-Id: <CAAnki7B=user-fad4db324a0a@xymon.invalid>

On Nov 1, 2013 10:50 PM, "deepak deore" <user-7b03b2a1ee70@xymon.invalid> wrote:
As ec2 instances by default doesn't respond icmp and I dont want to
enable icmp and ssh access to xymon server, what could be the best way to
check the instance's availability.
Can you attempt a connection on an unused port (eg 443 or 25) and see if
you get an "ICMP port unavailable" message indicated by a "connection
refused" result in netcat? That should be as effective as a ping.
Currently in my env i m doing following to check the availability:

1. Created server ext script which connects to bastion host and from
there it checks the ssh connection to the server.
    ssh -n bastion_host "nc -w 5 -vz ec2_instance 22" 2>&1
         if [ $? -eq 0 ]; then
             COLOR=green
          else
             COLOR=red
         fi
Perhaps if the ssh fails to connect to the bastion you can set the color to
"clear", and just make sure you bastion host is monitored.

J