Megacli collector should move to textfile collector

[brian-brazil]

We don't want to shell out (particularly to things that require root), so these should move to the textfile collector. We should provide scripts or binaries that can be run from cron

[matthiasr]

👍 instead of scripts, we could simply extract the current shelling parsing into their own CLI tool that will just do the thing once & write to a file or stdout. That way we can build on past work.

[brian-brazil]

In general I'm thinking we should have a good few of these as pure shell, in order to serve as examples. Go tends to be much longer code-wise, which may scare users off.

[grobie]

Last login has been removed.

[mattbostock]

Related to this issue, the current implementation of the MegaCli collector requires node_exporter to run as root or use setuid or setcap on the MegaCLI binary. It's also not possible to specify sudo when specifying -collector.megacli.command because exec.Command won't parse it.

To me, these are good reasons for this functionality to be moved out of the node_exporter.

[mattbostock]

I have a script that parses the JSON output from StorCLI (which I believe supersedes MegaCLI 1) and exposes Prometheus metrics on stdout ready for redirection into a file for the textfile collector.

Where should I put it? Should we have a directory in the node_exporter repo for example text collector scripts?

[brian-brazil]

A directory in this repo sounds good.

[mattbostock]

Raised #320

[discordianfish]

megacli is now marked as deprecated. We never deprecated features before, so it's up for discussion what happens next. We should definitely keep megacli in the 0.14 release but could remove it in 0.15. The question is more how much 0.14.x release we will have. But I'd say it should be gone in 0.15.

[Whissi]

megacli is now marked as deprecated. We never deprecated features before, so it's up for discussion what happens next.

I think it is a bad user experience when you just deprecate something without telling users where they should move to. So I would recommend to update https://github.com/prometheus/node_exporter/blob/master/README.md and add a "Replacement" column for example telling users to move to StorCLI text collect in this case. An additional note in megacli collector's source code would be helpful as well.

[discordianfish]

@Whissi Good idea! Want to submit a PR for that?