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Explain conversion for manualSelector

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Eric Tune 2016-02-22 09:59:53 -08:00
parent 7f613dbf15
commit 99e79720d0
1 changed files with 26 additions and 5 deletions
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docs/design/selector-generation.md
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@ -27,7 +27,7 @@ Documentation for other releases can be found at
<!-- END MUNGE: UNVERSIONED_WARNING --> <!-- END MUNGE: UNVERSIONED_WARNING -->
Proposed Design Design
============= =============
# Goals # Goals
@ -110,18 +110,39 @@ No changes
## Kubectl ## Kubectl
No required changes. No required changes.
Suggest moving SELECTOR to wide output of `kubectl get jobs` since users don't write the selector. Suggest moving SELECTOR to wide output of `kubectl get jobs` since users do not write the selector.
## Docs ## Docs
Remove examples that use selector and remove labels from pod templates. Remove examples that use selector and remove labels from pod templates.
Recommend `kubectl get jobs -l job-name=name` as the way to find pods of a job. Recommend `kubectl get jobs -l job-name=name` as the way to find pods of a job.
# Cross Version Compat # Conversion
`v1beta1` will not have a `job.spec.manualSelector` and will not provide a default selector. The following applies to Job, as well as to other types that adopt this pattern.
Conversion from v1beta1 to v1 will use the user-provided selector and set `job.spec.manualSelector=true`. - Type `extensions/v1beta1` gets a field called `job.spec.autoSelector`.
- Both the internal type and the `batch/v1` type will get `job.spec.manualSelector`.
- The fields `manualSelector` and `autoSelector` have opposite meanings.
- Each field defaults to false when unset, and so v1beta1 has a different default than v1 and internal. This is intentional: we want new
uses to default to the less error-prone behavior, and we do not want to change the behavior
of v1beta1.
*Note*: since the internal default is changing, client
library consumers that create Jobs may need to add "job.spec.manualSelector=true" to keep working, or switch
to auto selectors.
Conversion is as follows:
- `extensions/__internal` to `extensions/v1beta1`: the value of `__internal.Spec.ManualSelector` is defaulted to false if nil, negated, defaulted to nil if false, and written `v1beta1.Spec.AutoSelector`.
- `extensions/v1beta1` to `extensions/__internal`: the value of `v1beta1.SpecAutoSelector` is defaulted to false if nil, negated, defaulted to nil if false, and written to `__internal.Spec.ManualSelector`.
This conversion gives the following properties.
1. Users that previously used v1beta1 do not start seeing a new field when they get back objects.
2. Distinction between originally unset versus explicitly set to false is not preserved (would have been nice to do so, but requires more complicated
solution).
3. Users who only created v1beta1 examples or v1 examples, will not ever see the existence of either field.
4. Since v1beta1 are convertable to/from v1, the storage location (path in etcd) does not need to change, allowing scriptable rollforward/rollback.
# Future Work # Future Work