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Alert-driven monitoring

simpleobservability.com

11–20 of 48 posts

Re: Alert-driven monitoring

#11
post #8

For prior art on how to define alert conditions, see: https://en.wikipedia.org/wiki/Nelson_rules https://en.wikipedia.org/wiki/Western_Electric_rules https://en.wikipedia.org/wiki/Westgard_rules

Now we use purely statistical measures, which requires a probabilistic model. The name of the game is calibration.

Re: Alert-driven monitoring

#12

> Alerts should be actionable. If no action can or should be taken, then the alert is not needed. Also, the best alerts come from looking at actual failures you had and not trying to make up "good alerts" from thin air. After you have an outage, figure out what alerts would have caught it, and implement those.

I know something is going to happen if disk space runs out; I don't need to experience it first.

Re: Alert-driven monitoring

#13
post #12

> Alerts should be actionable. If no action can or should be taken, then the alert is not needed. Also, the best alerts come from looking at actual failures you had and not trying to make up "good alerts" from thin air. After you have an outage, figure out what alerts would have caught it, and implement those.

I know something is going to happen if disk space runs out; I don't need to experience it first.

Sure, but for every alert, there is exception.

ElasticSearch for example can be configured using ILM policies to fill up the disk then start deleting old records. I don't need to be woken up for disk filling up on those nodes.

Even worse is CPU/RAM alerts.

Re: Alert-driven monitoring

#14
I work writing analytics and monitoring for industrial equipment. We have hundreds of sensors sending back realtime data.

There was a period of time where people were writing alerts for the sake of it (i.e we have this sensor, when should we alert on it).

Nowadays we're strictly failure mode driven, this has meant lots of sensors aren't used in the analytics. They are however available to the experts to plot them for a more holistic view if required.

Re: Alert-driven monitoring

#15
post #12

Earlier quoted context omitted.

I know something is going to happen if disk space runs out; I don't need to experience it first.

Sure, but for every alert, there is exception. ElasticSearch for example can be configured using ILM policies to fill up the disk then start deleting old records. I don't need to be woken up for disk filling up on those nodes. Even worse is CPU/RAM alerts.

Alerts are for when things don't go as expected. You set up log rotation but an agent quietly breaks it or ES introduces a bug in it.

Re: Alert-driven monitoring

#16
> The real core of infrastructure monitoring isn’t dashboards. It’s the alerts.

“it’s not X it’s Y”

at this point when I see this pattern in writing I assume most if not all of it is AI generated - same with em-dashes.

This is not to discount the idea that alerts are more important than dashboards (I work directly in observability) - but just to say that I personally shut off reading anything else with these patterns because, generally speaking, the rest of the content is just not original or interesting.

Re: Alert-driven monitoring

#17
I certainly agree in spirit that the alerts are important, and should be actionable. But I wouldn't start at just "looking at the service" and then trying to define the first set of alerts.

Instead I would move up a level and start with a SLO for the various "business level" metrics you might care about. Things like "request latency", "successful requests", etc.

Then use the longer lookahead "error budget" burndowns to see where your error budget is being spent, and from there decide 1.) if the SLO needs adjusting, and/or 2.) if an alert is appropriate.

To cleanly answer those questions and iterate you'll need metrics, dashboards, traces, and logs. So then you're not just making dashboards because "its best practice", you're creating them to specifically help you measure if you're meeting your stated service objectives.

https://sre.google/sre-book/service-level-objectives/

Re: Alert-driven monitoring

#19

I like the ideas, but either it’s entirely LLM written or the writer has internalized “LLM voice”. At this point that is more distracting than helpful.

Do we really need this comment for every article? Who cares if AI wrote it if you like the ideas?

Re: Alert-driven monitoring

#20

> Alerts should be actionable. If no action can or should be taken, then the alert is not needed. Also, the best alerts come from looking at actual failures you had and not trying to make up "good alerts" from thin air. After you have an outage, figure out what alerts would have caught it, and implement those.

"looking at actual failures you had "

Also looking at failures others had, prior experience from yourself and others contribute to good alerts. You don't have to wait for failure to implement most of them. Most of that knowlege is also trained in to most LLM's nowadays. Just ask and then also verify sources, then implement. If you get to many alerts question if you needed them or if its noice. Its a constant trimming until you find the perfect alert setup.

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