[arch-general] Systemd email notifications

[Paul Gideon Dann]

On Thursday 13 Feb 2014 17:58:05 Damjan Georgievski wrote:
> > Yeah, I think it's possible to get systemd to poll a script, or there's
> > always cron (or a timer
> > unit) that should allow us to manually inspect a process and restart it if
> > necessary.  But it
> > would be cooler if there were shortcuts to features that we see in Monit
> > and other similar
> > systems; something like this in a unit file:
> > 
> > MaxMemoryThreshold=100M
> > MaxMemoryCheckInterval=30
> > MaxMemoryIntervalThrehold=2
> > 
> > The memory is then checked every 30 seconds.  When the unit exceeds this
> > amount of RAM
> > for 2 successive intervals, the unit is restarted.
> 
> there is setting of ulimits in systemd, it's much more brutal though, will
> not wait for 30 seconds
> 
> man systemd.exec

Thank you; I didn't know about that, and it's very interesting.  The limits are indeed a bit 
strict for server process monitoring. I imagine it would be really handy as a failsafe in 
embedded environments, though.

The great benefit of them is that (as far as I can tell), it's the kernel that enforces the limits, 
so there's no polling involved.  I suppose that the gold standard for monitoring would be a 
combination of the two: a userspace component (e.g. systemd or associated monitoring 
tool) registering to receive events from the kernel on certain resource thresholds for a 
process, so that e.g. time spent above RAM threshold could be monitored accurately in an 
event-based way, without polling.  That would be awesome.

Paul