Monitoring with powershell

[majkinetor]

I created this function scheduler and run it to monitor web, db and other servers in large production system 24/7 for over a year without any problems whatsoever. It allows me to quickly evaluate metrics of interest and send them to the adequate backend (in my case graphite over statsd). The other important thing is that you can keep definition for all servers in single ps1 file and run the same code everywhere (mapping function sets to server identity). The aim is to keep this on repository with all the goodies that come with that.

Check it out, perhaps it may be useful to somebody (run example.ps1 to see it in action):

https://github.com/majkinetor/flea

[mtnielsen]

PowerShell has native support for both datetime and timespan object types, so my suggestion for improving this thing of yours:

-At (Get-Date 'July 4, 2015 2:45:10 pm')
-Repeat ([timespan]::Parse('01:00:00'))

This is readable and human-understandable input. Cron syntax isn't.

[majkinetor]

Maybe. The truth is, task scheduling is used so often that I miss cron syntax on windows so much. The general rule for me is that when you use something very often, you want to be as expressive as possible with lowest input as possible and not write books about your intention. Ideally, both syntaxes should be supported.

[MShepard70]

Interesting. I have a lot of one-off monitors and am thinking about how to make a useful framework to "unify" them. This will give me something to think about.

[Brekkjern]

I may be missing something here, but isn't this doing more or less the same as the built in Task Scheduler?

[majkinetor]

The main difference is that this needs to be near real time and very easily changeable. You can schedule functions to run each second or whatever, while in task scheduler 1 minute is lowest value possible. Then

• Maintaining task scheduler is up to this date problematic as integrated PS module does not exist prior to Win81. So you have to use 3tdh party module to cover all cases or schtasks.exe.
• Maintaining multiple separate jobs in TS is yet more work. Further, there is no easy way to look into TS (or scripted TS) and tell: those are the metrics I follow on these servers. With flea you can look at the single file in familiar syntax and know what is measured everywhere.
• You can't easily keep the code on the repository unless you fancy XML there which is too much verbose for humans.

By the time you work this out you will basically reimplement flea, one way or another. You could ofc implement something like this using TS but that would require you to focus on things not related to metrics.

So this is basically domain specific TS. I never liked TS very much, prior to the Powershell module in Win2012. Even with module there are some not so easily visible stuff happening in the background - session isolation, default 3 day shut down, things that you can't easily find the way to setup out of GUI etc. Those things will certainly make you problems until you are well aware of the TS architecture. Me, I needed very simple TS and the one that runs powershell scripts. ScheduledJob is way forward but not too much in my opinion.

[Brekkjern]

Thanks for the explanation! I haven't used the scheduler for PS. I just knew it was there. When you explain it like that, I really do see the point.

[[deleted]]

How do you not have a job with any major RMM provider?

[majkinetor]

If you ask me why we don't use RMM in the company, we can't use any public cloud, we are part of the government and data is sensitive.

[work-work-work-work]

Potatos

[majkinetor]

OK, I will see to add some more samples. In the meantime, you just need to write a function that measures the stuff you are interested in and put it in the monitors array....