Migrate kubectl debug KEP to new format

Author: verb

keps/sig-cli/20190805-kubectl-debug.md renamed to keps/sig-cli/1441-kubectl-debug/README.md

@@ -1,29 +1,4 @@
----
-title: kubectl debug
-authors:
-  - "@verb"
-owning-sig: sig-cli
-participating-sigs:
-  - sig-cli
-  - sig-node
-reviewers:
-  - "@aylei"
-  - "@soltysh"
-approvers:
-  - "@pwittrock"
-  - "@soltysh"
-editor: TBD
-creation-date: 2019-08-05
-last-updated: 2019-08-06
-status: implementable
-see-also:
-  - "/keps/sig-node/20190212-ephemeral-containers.md"
-  - "/keps/sig-release/20190316-rebase-images-to-distroless.md"
----
-
-# Pod Troubleshooting
-
-## Table of Contents
+# KEP-1441: kubectl debug
 
 <!-- toc -->
 - [Release Signoff Checklist](#release-signoff-checklist)
@@ -50,40 +25,44 @@ see-also:
     - [Debugging](#debugging)
     - [Automation](#automation)
     - [Technical Support](#technical-support)
-  - [Implementation Details/Notes/Constraints](#implementation-detailsnotesconstraints)
+  - [Notes/Constraints/Caveats (Optional)](#notesconstraintscaveats-optional)
   - [Risks and Mitigations](#risks-and-mitigations)
 - [Design Details](#design-details)
   - [Test Plan](#test-plan)
   - [Graduation Criteria](#graduation-criteria)
     - [Alpha -&gt; Beta Graduation](#alpha---beta-graduation)
     - [Beta -&gt; GA Graduation](#beta---ga-graduation)
+  - [Upgrade / Downgrade Strategy](#upgrade--downgrade-strategy)
+  - [Version Skew Strategy](#version-skew-strategy)
+- [Production Readiness Review Questionnaire](#production-readiness-review-questionnaire)
 - [Implementation History](#implementation-history)
+- [Drawbacks](#drawbacks)
 - [Alternatives](#alternatives)
 <!-- /toc -->
 
 ## Release Signoff Checklist
 
-For enhancements that make changes to code or processes/procedures in core Kubernetes i.e., [kubernetes/kubernetes], we require the following Release Signoff checklist to be completed.
+Items marked with (R) are required *prior to targeting to a milestone / release*.
 
-Check these off as they are completed for the Release Team to track. These checklist items _must_ be updated for the enhancement to be released.
-
-- [ ] kubernetes/enhancements issue in release milestone, which links to KEP (this should be a link to the KEP location in kubernetes/enhancements, not the initial KEP PR)
-- [ ] KEP approvers have set the KEP status to `implementable`
-- [ ] Design details are appropriately documented
-- [ ] Test plan is in place, giving consideration to SIG Architecture and SIG Testing input
-- [ ] Graduation criteria is in place
+- [x] (R) Enhancement issue in release milestone, which links to KEP dir in [kubernetes/enhancements] (not the initial KEP PR)
+- [x] (R) KEP approvers have approved the KEP status as `implementable`
+- [ ] (R) Design details are appropriately documented
+- [ ] (R) Test plan is in place, giving consideration to SIG Architecture and SIG Testing input
+- [ ] (R) Graduation criteria is in place
+- [ ] (R) Production readiness review completed
+- [ ] Production readiness review approved
 - [ ] "Implementation History" section is up-to-date for milestone
 - [ ] User-facing documentation has been created in [kubernetes/website], for publication to [kubernetes.io]
-- [ ] Supporting documentation e.g., additional design documents, links to mailing list discussions/SIG meetings, relevant PRs/issues, release notes
-
-**Note:** Any PRs to move a KEP to `implementable` or significant changes once it is marked `implementable` should be approved by each of the KEP approvers. If any of those approvers is no longer appropriate than changes to that list should be approved by the remaining approvers and/or the owning SIG (or SIG-arch for cross cutting KEPs).
+- [ ] Supporting documentation—e.g., additional design documents, links to mailing list discussions/SIG meetings, relevant PRs/issues, release notes
 
+<!--
 **Note:** This checklist is iterative and should be reviewed and updated every time this enhancement is being considered for a milestone.
+-->
 
 [kubernetes.io]: https://kubernetes.io/
-[kubernetes/enhancements]: https://github.com/kubernetes/enhancements/issues
-[kubernetes/kubernetes]: https://github.com/kubernetes/kubernetes
-[kubernetes/website]: https://github.com/kubernetes/website
+[kubernetes/enhancements]: https://git.k8s.io/enhancements
+[kubernetes/kubernetes]: https://git.k8s.io/kubernetes
+[kubernetes/website]: https://git.k8s.io/website
 
 ## Summary
 
@@ -436,7 +415,7 @@ is to run his team's autodiagnose script:
 % kubectl debug --image=k8s.gcr.io/autodiagnose nginx-pod-1234
 ```
 
-### Implementation Details/Notes/Constraints
+### Notes/Constraints/Caveats
 
 1.  There's an output stream race inherent to creating then attaching a
     container which causes output generated between the start and attach to go
@@ -476,13 +455,261 @@ test prior to Alpha -> Beta graduation.
 
 - [ ] Ephemeral Containers are GA
 
+### Upgrade / Downgrade Strategy
+
+<!--
+If applicable, how will the component be upgraded and downgraded? Make sure
+this is in the test plan.
+
+Consider the following in developing an upgrade/downgrade strategy for this
+enhancement:
+- What changes (in invocations, configurations, API use, etc.) is an existing
+  cluster required to make on upgrade, in order to maintain previous behavior?
+- What changes (in invocations, configurations, API use, etc.) is an existing
+  cluster required to make on upgrade, in order to make use of the enhancement?
+-->
+
+### Version Skew Strategy
+
+<!--
+If applicable, how will the component handle version skew with other
+components? What are the guarantees? Make sure this is in the test plan.
+
+Consider the following in developing a version skew strategy for this
+enhancement:
+- Does this enhancement involve coordinating behavior in the control plane and
+  in the kubelet? How does an n-2 kubelet without this feature available behave
+  when this feature is used?
+- Will any other components on the node change? For example, changes to CSI,
+  CRI or CNI may require updating that component before the kubelet.
+-->
+
+## Production Readiness Review Questionnaire
+
+<!--
+
+Production readiness reviews are intended to ensure that features merging into
+Kubernetes are observable, scalable and supportable; can be safely operated in
+production environments, and can be disabled or rolled back in the event they
+cause increased failures in production. See more in the PRR KEP at
+https://git.k8s.io/enhancements/keps/sig-architecture/20190731-production-readiness-review-process.md.
+
+The production readiness review questionnaire must be completed for features in
+v1.19 or later, but is non-blocking at this time. That is, approval is not
+required in order to be in the release.
+
+In some cases, the questions below should also have answers in `kep.yaml`. This
+is to enable automation to verify the presence of the review, and to reduce review
+burden and latency.
+
+The KEP must have a approver from the
+[`prod-readiness-approvers`](http://git.k8s.io/enhancements/OWNERS_ALIASES)
+team. Please reach out on the
+[#prod-readiness](https://kubernetes.slack.com/archives/CPNHUMN74) channel if
+you need any help or guidance.
+
+-->
+
+```
+<<[UNRESOLVED copied over from template and needs to be filled. ]>>
+
+### Feature Enablement and Rollback
+
+_This section must be completed when targeting alpha to a release._
+
+* **How can this feature be enabled / disabled in a live cluster?**
+  - [ ] Feature gate (also fill in values in `kep.yaml`)
+    - Feature gate name:
+    - Components depending on the feature gate:
+  - [ ] Other
+    - Describe the mechanism:
+    - Will enabling / disabling the feature require downtime of the control
+      plane?
+    - Will enabling / disabling the feature require downtime or reprovisioning
+      of a node? (Do not assume `Dynamic Kubelet Config` feature is enabled).
+
+* **Does enabling the feature change any default behavior?**
+  Any change of default behavior may be surprising to users or break existing
+  automations, so be extremely careful here.
+
+* **Can the feature be disabled once it has been enabled (i.e. can we roll back
+  the enablement)?**
+  Also set `disable-supported` to `true` or `false` in `kep.yaml`.
+  Describe the consequences on existing workloads (e.g., if this is a runtime
+  feature, can it break the existing applications?).
+
+* **What happens if we reenable the feature if it was previously rolled back?**
+
+* **Are there any tests for feature enablement/disablement?**
+  The e2e framework does not currently support enabling or disabling feature
+  gates. However, unit tests in each component dealing with managing data, created
+  with and without the feature, are necessary. At the very least, think about
+  conversion tests if API types are being modified.
+
+### Rollout, Upgrade and Rollback Planning
+
+_This section must be completed when targeting beta graduation to a release._
+
+* **How can a rollout fail? Can it impact already running workloads?**
+  Try to be as paranoid as possible - e.g., what if some components will restart
+   mid-rollout?
+
+* **What specific metrics should inform a rollback?**
+
+* **Were upgrade and rollback tested? Was the upgrade->downgrade->upgrade path tested?**
+  Describe manual testing that was done and the outcomes.
+  Longer term, we may want to require automated upgrade/rollback tests, but we
+  are missing a bunch of machinery and tooling and can't do that now.
+
+* **Is the rollout accompanied by any deprecations and/or removals of features, APIs, 
+fields of API types, flags, etc.?**
+  Even if applying deprecation policies, they may still surprise some users.
+
+### Monitoring Requirements
+
+_This section must be completed when targeting beta graduation to a release._
+
+* **How can an operator determine if the feature is in use by workloads?**
+  Ideally, this should be a metric. Operations against the Kubernetes API (e.g.,
+  checking if there are objects with field X set) may be a last resort. Avoid
+  logs or events for this purpose.
+
+* **What are the SLIs (Service Level Indicators) an operator can use to determine 
+the health of the service?**
+  - [ ] Metrics
+    - Metric name:
+    - [Optional] Aggregation method:
+    - Components exposing the metric:
+  - [ ] Other (treat as last resort)
+    - Details:
+
+* **What are the reasonable SLOs (Service Level Objectives) for the above SLIs?**
+  At a high level, this usually will be in the form of "high percentile of SLI
+  per day <= X". It's impossible to provide comprehensive guidance, but at the very
+  high level (needs more precise definitions) those may be things like:
+  - per-day percentage of API calls finishing with 5XX errors <= 1%
+  - 99% percentile over day of absolute value from (job creation time minus expected
+    job creation time) for cron job <= 10%
+  - 99,9% of /health requests per day finish with 200 code
+
+* **Are there any missing metrics that would be useful to have to improve observability 
+of this feature?**
+  Describe the metrics themselves and the reasons why they weren't added (e.g., cost,
+  implementation difficulties, etc.).
+
+### Dependencies
+
+_This section must be completed when targeting beta graduation to a release._
+
+* **Does this feature depend on any specific services running in the cluster?**
+  Think about both cluster-level services (e.g. metrics-server) as well
+  as node-level agents (e.g. specific version of CRI). Focus on external or
+  optional services that are needed. For example, if this feature depends on
+  a cloud provider API, or upon an external software-defined storage or network
+  control plane.
+
+  For each of these, fill in the following—thinking about running existing user workloads
+  and creating new ones, as well as about cluster-level services (e.g. DNS):
+  - [Dependency name]
+    - Usage description:
+      - Impact of its outage on the feature:
+      - Impact of its degraded performance or high-error rates on the feature:
+
+
+### Scalability
+
+_For alpha, this section is encouraged: reviewers should consider these questions
+and attempt to answer them._
+
+_For beta, this section is required: reviewers must answer these questions._
+
+_For GA, this section is required: approvers should be able to confirm the
+previous answers based on experience in the field._
+
+* **Will enabling / using this feature result in any new API calls?**
+  Describe them, providing:
+  - API call type (e.g. PATCH pods)
+  - estimated throughput
+  - originating component(s) (e.g. Kubelet, Feature-X-controller)
+  focusing mostly on:
+  - components listing and/or watching resources they didn't before
+  - API calls that may be triggered by changes of some Kubernetes resources
+    (e.g. update of object X triggers new updates of object Y)
+  - periodic API calls to reconcile state (e.g. periodic fetching state,
+    heartbeats, leader election, etc.)
+
+* **Will enabling / using this feature result in introducing new API types?**
+  Describe them, providing:
+  - API type
+  - Supported number of objects per cluster
+  - Supported number of objects per namespace (for namespace-scoped objects)
+
+* **Will enabling / using this feature result in any new calls to the cloud 
+provider?**
+
+* **Will enabling / using this feature result in increasing size or count of 
+the existing API objects?**
+  Describe them, providing:
+  - API type(s):
+  - Estimated increase in size: (e.g., new annotation of size 32B)
+  - Estimated amount of new objects: (e.g., new Object X for every existing Pod)
+
+* **Will enabling / using this feature result in increasing time taken by any 
+operations covered by [existing SLIs/SLOs]?**
+  Think about adding additional work or introducing new steps in between
+  (e.g. need to do X to start a container), etc. Please describe the details.
+
+* **Will enabling / using this feature result in non-negligible increase of 
+resource usage (CPU, RAM, disk, IO, ...) in any components?**
+  Things to keep in mind include: additional in-memory state, additional
+  non-trivial computations, excessive access to disks (including increased log
+  volume), significant amount of data sent and/or received over network, etc.
+  This through this both in small and large cases, again with respect to the
+  [supported limits].
+
+### Troubleshooting
+
+The Troubleshooting section currently serves the `Playbook` role. We may consider
+splitting it into a dedicated `Playbook` document (potentially with some monitoring
+details). For now, we leave it here.
+
+_This section must be completed when targeting beta graduation to a release._
+
+* **How does this feature react if the API server and/or etcd is unavailable?**
+
+* **What are other known failure modes?**
+  For each of them, fill in the following information by copying the below template:
+  - [Failure mode brief description]
+    - Detection: How can it be detected via metrics? Stated another way:
+      how can an operator troubleshoot without logging into a master or worker node?
+    - Mitigations: What can be done to stop the bleeding, especially for already
+      running user workloads?
+    - Diagnostics: What are the useful log messages and their required logging
+      levels that could help debug the issue?
+      Not required until feature graduated to beta.
+    - Testing: Are there any tests for failure mode? If not, describe why.
+
+* **What steps should be taken if SLOs are not being met to determine the problem?**
+
+[supported limits]: https://git.k8s.io/community//sig-scalability/configs-and-limits/thresholds.md
+[existing SLIs/SLOs]: https://git.k8s.io/community/sig-scalability/slos/slos.md#kubernetes-slisslos
+
+<<[/UNRESOLVED]>>
+```
+
 ## Implementation History
 
 - *2019-08-06*: Initial KEP draft
 - *2019-12-05*: Updated KEP for expanded debug targets.
 - *2020-01-09*: Updated KEP for debugging nodes and mark implementable.
 - *2020-01-15*: Added test plan.
 
+## Drawbacks
+
+<!--
+Why should this KEP _not_ be implemented?
+-->
+
 ## Alternatives
 
 An exhaustive list of alternatives to ephemeral containers is included in the