On occasion I’ve been to clients where ICMP is turned off
at the routers. This means servers will not respond to a ping if
you wanted to determine if a server is alive. The following script
can be used to test an ssh connection instead and timeout within a
reasonable time. In this case 7 seconds.
user=troy
do_ssh()
{
ssh $user@$1 $2 &
PID=$!
(sleep 7; kill $PID >/dev/null 2>&1) &
wait $PID >/dev/null 2>&1
}
do_ssh $host 'date' >/dev/null 2>&1
if [[ $? -gt 0 ]];then echo
"${host} : SSH Timeout"
exit 1
else
# SSH is ok, so run your command!
ssh $host 'ps -ef'
fi |
