Great! will implement the solution to set the color to green if bastion host is not available.
BTW .... all the hosts i m monitoring are inside amazon vpc and xymon is outside of vpc. So xymon cant reach to the clients, it has to go through bastion host, so i cant do the netcat to any clients other than bastion.
On Fri, Nov 1, 2013 at 8:44 PM, Jeremy Laidman <jlaidman at rebel-it.com.au>wrote:
On Nov 1, 2013 10:50 PM, "deepak deore" <deepakdeore2004 at gmail.com> 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:
- 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