[j-nsp] DHCP relay monitoring

[Nathan Ward]

> On 9/07/2020, at 23:48, Baldur Norddahl <baldur at gigabit.dk> wrote:
> 
> Hello
> 
> On one of my MX204 routers the DHCP relay crashes after some running time and the process stops. It is not restarted automatically but will start again with the following command:

What version are you on? Are you running IPv6? PPP with IPv6 over the top?

> admin at gc-edge1> restart dhcp-service
> error: Junos Dynamic Host Configuration Protocol process is not running
> Junos Dynamic Host Configuration Protocol process started, pid 72256
> 
> I can open a case with JTAC for the cause of the crash, but I am thinking about how to monitor the relay. None of my current monitoring tools detects this situation and it is actually quite critical. With no relay the customers DHCP lease may expire. To a certain extend the customers will be using unicast to the DHCP server and not many will feel it right away, but soon enough we will have customers that can not get online after rebooting their CPE etc.
> 
> What options do we have for monitoring running processes on the router? Are there other processes than DHCP that should be monitored too?

One option I’ve used for very similar sounding issues is doing this on the DHCP server, collecting stats for requests per giaddr and alerting when they’re suddenly low.

You might see something in the logs when DHCP crashes and can alarm on that with your chosen syslog system.

JUNIPER-JDHCP-MIB may be useful - though when the DHCP process is dead you may get polling timeouts. If your polling system can alarm on that you might get usefulness there.
 
--
Nathan Ward