Re: [monit] Howto monitor multiple instances zope ?

[Martin Pala]

Monit starts the instances sequentially ... if the services go up too 
fast, you can modify the startup script to control the parallelism.

Simple way could be for example to touch some flag file in the beginning 
 and remove it at the end of the start script. The script can sleep 
till the number of starting instances will drop bellow the requested level.

Dummy script (not tested - may need fixes):
--8<--
#!/bin/bash

# parallelism
BARRIER=2

# where to store the startup flags
BARRIER_DIR="var/zope/parallel/"

# check that the directory exists otherwise create it
test -d $BARRIER || mkdir -p $BARRIER

# wait for number of starting instances to drop bellow limit
while [ `ls /var/zope/parallel/` -lt $BARRIER ]
do
  sleep 1;
done

# we are in critical section now - set flag
touch /var/zope/parallel/$$

# do zope startup
<start zope>

# remove the flag which will allow to start the waiting instances
rm -f touch /var/zope/parallel/$$
--8<--


Note however that this is just simple example - it may have problems 
such as race condition when creating the flag, or if the script will be 
interrupted and will left the ghost flag file (didn't had chance to 
cleanup), then if the ghost/orphaned flags count will be above the 
limit, it will block the instances from startup, so as you can see, the 
method needs tunning ;)



Btw. the startup throttling is interesting idea - i'll add it to the 
wishlist.


Thanks,
Martin



kat wrote:
> Hi,
>
> First sorry for my english.
>
> I try to configure monit to monitor multiple instances zope on the same 
> server.
>
> My problem is that monit start all instances zope (and other monitored 
> services) at the same time.
>
> What is the best way to avoid that behaviour ?
>
> When monit start 2 or more instance zope at the same time the server is 
> a little overloaded.
>
> So when you have 10 instances zope ...
>
> Thanks
>
>
> --
> To unsubscribe:
> http://lists.nongnu.org/mailman/listinfo/monit-general