Add total number of connected minions

[julioz]

On every scrape, the exporter should include a gauge metric with the number of connected minions to that master node.
This way we can keep track of new minions connected, but more importantly, when minions disappear.

[kpetremann]

hello @julioz,

What about counting the number of minion using salt_responses_total metric?

The exporter is passive, it only watches the event queue. So I don't see how we could know that a minion disappeared, except if your are sending requests targeting all minions. But if you do, the salt_responses_total would do the trick.

Note: where I work, we use another simple active exporter only to "ping" our minions (not open-source):

• It sends a test.ping request to all minions via the API.
• Then it parses the results to count number of responding and not responding minions.

But this is not always reliable depending on your targets workload: sometimes the minion does not respond to test.ping before the timeout because it was doing something else.

[julioz]

The exporter is passive, it only watches the event queue

Got it. Is your intent to keep it passive-only, or is salt-exporter intended to grow for "all things salt"? If the latter, I'd imagine a salt-run manage.alived could be a good way to count "up" minions without sending test.ping commands that could hang.

[kpetremann]

The initial intent was to keep it passive-only.

But if there is a need, I am not opposed to make salt-exporter grow.

My two concerns are:

• keeping the salt-exporter as simple as possible for the user (easy to setup and understand).
• is there an overlap with an already an exporter doing this kind of feature? I wrote this exporter because I did not find any leveraging the IPC event queue. TBH, I am hesitating between having an "all things salt" versus installing one or two additional exporters if they already exists. I did not check the current status of Saltstack exporters recently.

[julioz]

Note: where I work, we use another simple active exporter only to "ping" our minions (not open-source):

We ended up implementing something similar, but based on a homegrown active salt exporter. Feel free to close this issue if there are no plans to implement similarly in this exporter 👍

[kpetremann]

ok great :) thanks for the feedback.
I think this is the best approach for now.

I'll close the issue.
If I plan to add this kind of feature (Salt API client based metrics) in the future, I'll mention this issue.

[kpetremann]

hello @julioz,

The PR #57 might interest you (available in v0.9.0).