Introduce metrics for pdcsi node

[hajiler]

What type of PR is this?
/kind feature

What this PR does / why we need it:
This PR adds metrics capability for the PDCSI node server. Metrics enable us to define SLO/Alerts for the node server. This PR specifically adds a metric for mount errors.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

adds metrics for node server including:
- 'process_start_time': start time of the container for use in metric scraping
- 'node_mount_errors': error types which occur during volume mounting

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: hajiler
Once this PR has been reviewed and has the lgtm label, please assign leiyiz for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[k8s-ci-robot]

Welcome @hajiler!

It looks like this is your first PR to kubernetes-sigs/gcp-compute-persistent-disk-csi-driver 🎉. Please refer to our pull request process documentation to help your PR have a smooth ride to approval.

You will be prompted by a bot to use commands during the review process. Do not be afraid to follow the prompts! It is okay to experiment. Here is the bot commands documentation.

You can also check if kubernetes-sigs/gcp-compute-persistent-disk-csi-driver has its own contribution guidelines.

You may want to refer to our testing guide if you run into trouble with your tests not passing.

If you are having difficulty getting your pull request seen, please follow the recommended escalation practices. Also, for tips and tricks in the contribution process you may want to read the Kubernetes contributor cheat sheet. We want to make sure your contribution gets all the attention it needs!

Thank you, and welcome to Kubernetes. 😃

[k8s-ci-robot]

Hi @hajiler. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[sunnylovestiramisu]

/ok-to-test

[k8s-ci-robot]

@hajiler: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-gcp-compute-persistent-disk-csi-driver-e2e-windows-2019	4cf2e9b	link	false	/test pull-gcp-compute-persistent-disk-csi-driver-e2e-windows-2019

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.

[hajiler]

/assign msau

[k8s-ci-robot]

@hajiler: GitHub didn't allow me to assign the following users: msau.

Note that only kubernetes-sigs members with read permissions, repo collaborators and people who have commented on this issue/PR can be assigned. Additionally, issues/PRs can only have 10 assignees at the same time.
For more information please see the contributor guide

In response to this:

/assign msau

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[tyuchn]

/assign msau

[k8s-ci-robot]

@tyuchn: GitHub didn't allow me to assign the following users: msau.

Note that only kubernetes-sigs members with read permissions, repo collaborators and people who have commented on this issue/PR can be assigned. Additionally, issues/PRs can only have 10 assignees at the same time.
For more information please see the contributor guide

In response to this:

/assign msau

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[sunnylovestiramisu]

/assign @msau42

[sunnylovestiramisu]

Do we have a SLO design doc for this metrics? We probably also want info of "driver_name", "grpc_status_code", "disk_type" etc. extra information?

[sunnylovestiramisu]

The thing is we need success calls and error calls to calculate the right SLO, so we probably need to emit both.

[msau42]

Check out existing csi/k8s volume metrics to follow similar patterns.

[k8s-ci-robot]

PR needs rebase.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.