Re: [monit] How to Achieve "if x restarts within y cycles then exec ..."

[Art Age Software]

> Yes, this could work. Optionally it could be possible to use the pidfile
> using similar approach:
>
> --8<--
> check process mysql with pidfile /var/run/mysqld/mysqld.pid
>   mode manual
>   every 2 cycles
>   if failed unix "/var/lib/mysql/mysql.sock" then restart
>   if failed host localhost port 3306 protocol mysql then restart
>   if 5 restarts within 10 cycles then timeout
>
> check file mysql_pidfile with path /var/run/mysqld/mysqld.pid
>   mode manual
>   if changed timestamp for 5 cycles then exec
> "/usr/lib/heartbeat/hb_standby"
> --8<--
>
> On restart the script will change the timestamp of the pidfile => the second
> service check can trigger failover/standby based on it.

I like your approach better because it seems more reliable. With my
approach, I think it is possible for the mysql protocol checks to
succeed if the timing is just right (i.e. the check happens between
restart and crash).

With your approach, should the condition match exactly for both
checks? For example:

if 5 restarts within 10 cycles then timeout
if changed timestamp 5 times in 10 cycles then exec "hb_standby"

Will it then be guaranteed that if the restart/timeout condition
occurs, then the changed timestamp condition/action will also occur?
Or is there any potential for funny timing anomalies?

Thanks again.