Make StatefulSets safe during cluster failure

[smarterclayton]

Description

In order to safely run clustered software, the PetSet controller (and other high level components) must be able to ensure only one instance of a pet is running at any one time. This change will correct the core cluster logic controlling pod deletion to ensure pods can be used with this guarantee, and set direction for future improvements for reliable clusters around fencing and storage safety.

Progress Tracker

• Alpha
  • Write and maintain draft quality doc
    • During development keep a doc up-to-date about the desired experience of the feature and how someone can try the feature in its current state. Think of it as the README of your new feature and a skeleton for the docs to be written before the Kubernetes release. Paste link to Google Doc: DOC-LINK
  • Design Approval
    • Design Proposal. Proposal - Pod safety and termination guarantees kubernetes#34160
    • Decide which repo this feature's code will be checked into. Not everything needs to land in the core kubernetes repo. kubernetes/kubernetes
    • Initial API review (if API). Maybe same PR as design doc. PR-NUMBER
      • Any code that changes an API (/pkg/apis/...)
      • cc @kubernetes/api
    • Identify shepherd (your SIG lead and/or [email protected] will be able to help you). My Shepherd is: [email protected] (and/or GH Handle)
      • A shepherd is an individual who will help acquaint you with the process of getting your feature into the repo, identify reviewers and provide feedback on the feature. They are not (necessarily) the code reviewer of the feature, or tech lead for the area.
      • The shepherd is not responsible for showing up to Kubernetes-PM meetings and/or communicating if the feature is on-track to make the release goals. That is still your responsibility.
    • Identify secondary/backup contact point. My Secondary Contact Point is: [email protected] (and/or GH Handle)
  • Write (code + tests + docs) then get them merged. ALL-PR-NUMBERS
    • Code needs to be disabled by default. Verified by code OWNERS
    • Minimal testing
    • Minimal docs
      • cc @kubernetes/docs on docs PR
      • cc @kubernetes/feature-reviewers on this issue to get approval before checking this off
      • New apis: Glossary Section Item in the docs repo: kubernetes/kubernetes.github.io
    • Update release notes
• Beta
  • Testing is sufficient for beta
  • User docs with tutorials
    • Updated walkthrough / tutorial in the docs repo: kubernetes/kubernetes.github.io
    • cc @kubernetes/docs on docs PR
    • cc @kubernetes/feature-reviewers on this issue to get approval before checking this off
  • Thorough API review
    • cc @kubernetes/api
• Stable
  • docs/proposals/foo.md moved to docs/design/foo.md
    • cc @kubernetes/feature-reviewers on this issue to get approval before checking this off
  • Soak, load testing
  • detailed user docs and examples
    • cc @kubernetes/docs
    • cc @kubernetes/feature-reviewers on this issue to get approval before checking this off

FEATURE_STATUS is used for feature tracking and to be updated by @kubernetes/feature-reviewers.
FEATURE_STATUS: IN_DEVELOPMENT

More advice:

Design

• Once you get LGTM from a @kubernetes/feature-reviewers member, you can check this checkbox, and the reviewer will apply the "design-complete" label.

Coding

• Use as many PRs as you need. Write tests in the same or different PRs, as is convenient for you.
• As each PR is merged, add a comment to this issue referencing the PRs. Code goes in the https://github.com/kubernetes/kubernetes repository,
  and sometimes https://github.com/kubernetes/contrib, or other repos.
• When you are done with the code, apply the "code-complete" label.
• When the feature has user docs, please add a comment mentioning @kubernetes/feature-reviewers and they will
  check that the code matches the proposed feature and design, and that everything is done, and that there is adequate
  testing. They won't do detailed code review: that already happened when your PRs were reviewed.
  When that is done, you can check this box and the reviewer will apply the "code-complete" label.

Docs

• Write user docs and get them merged in.
• User docs go into https://github.com/kubernetes/kubernetes.github.io.
• When the feature has user docs, please add a comment mentioning @kubernetes/docs.
• When you get LGTM, you can check this checkbox, and the reviewer will apply the "docs-complete" label.

[idvoretskyi]

@smarterclayton please, update the naming and description with regards to "StatefulSets" renaming.

[jaredbhatti]

Ping. Is there a docs PR for this?

[erictune]

This is covered by kubernetes/website#1774

[erictune]

I've relabeled this as beta, not alpha. SS is beta. The change to node controller behavior sorta sidestepped the whole alpha/beta/GA thing.

[idvoretskyi]

@erictune thank you.

[idvoretskyi]

@smarterclayton @erictune can you confirm that this item targets stable in 1.6?

[erictune]

Statefulset set will still be beta in 1.6. Progress will be made in this area.

…

On Dec 13, 2016 10:04 AM, "Ihor Dvoretskyi" ***@***.***> wrote: @smarterclayton <https://github.com/smarterclayton> @erictune <https://github.com/erictune> can you confirm that this item targets stable in 1.6? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#119 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AHuudg4XhIkZ38Wpc02FD0BbuLUXmPGwks5rHt4IgaJpZM4KR26q> .

[smarterclayton]

This is stable in 1.6, ongoing work for DaemonSets is being tracked in #353