### SIG Cluster Lifecycle

  * kubeadm: The `:Etcd` struct has been refactored in the v1alpha2 API. All the options now reside under either `.Etcd.Local` or `.Etcd.External`. Automatic conversions from the v1alpha1 API are supported. ([#64066](https://github.com/kubernetes/kubernetes/pull/64066), [@luxas](https://github.com/luxas))

"+o]||l["* "+o]))for(i in l)if((s=i.split(" "))[1]===o&&(a=l[u+" "+s[0]]||l["* "+s[0]])){!0===a?a=l[i]:!0!==l[i]&&(o=s[0],c.unshift(s[1]));break}if(!0!==a)if(a&&e["throws"])t=a(t);else try{t=a(t)}catch(e){return{state:"parsererror",error:a?e:"No conversion from "+u+" to "+o}}}return{state:"success",data:t}}(v,s,T,i),i?(v.ifModified&&((u=T.getResponseHeader("Last-Modified"))&&(ce.lastModified[f]=u),(u=T.getResponseHeader("etag"))&&(ce.etag[f]=u)),204===e||"HEAD"===v.type?l="nocontent":304===e?l="n...

does not support protobuf encoding, if you roll back to 1.5 after upgrading to
protobuf you will be forced to restore from backup, and you will lose any changes
since you converted to protobuf.  After conversion to protobuf, you should
validate the correct operation of your cluster thoroughly before returning it
to normal operation.

Backups are always a good precaution, particularly around upgrades, but this

- Timeouts set in ListOptions for clients are also be respected locally ([#70998](https://github.com/kubernetes/kubernetes/pull/70998), [@deads2k](https://github.com/deads2k))
- Added support for CRD conversion webhook ([#67006](https://github.com/kubernetes/kubernetes/pull/67006), [@mbohlool](https://github.com/mbohlool))

"+o]||l["* "+o]))for(i in l)if((s=i.split(" "))[1]===o&&(a=l[u+" "+s[0]]||l["* "+s[0]])){!0===a?a=l[i]:!0!==l[i]&&(o=s[0],c.unshift(s[1]));break}if(!0!==a)if(a&&e["throws"])t=a(t);else try{t=a(t)}catch(e){return{state:"parsererror",error:a?e:"No conversion from "+u+" to "+o}}}return{state:"success",data:t}}(v,s,T,i),i?(v.ifModified&&((u=T.getResponseHeader("Last-Modified"))&&(ce.lastModified[f]=u),(u=T.getResponseHeader("etag"))&&(ce.etag[f]=u)),204===e||"HEAD"===v.type?l="nocontent":304===e?l="n...

* Fix issue with kubectl annotate when --resource-version is provided. ([#29319](https://github.com/kubernetes/kubernetes/pull/29319), [@juanvallejo](https://github.com/juanvallejo))
* Reverted conversion of influx-db to Pet Set, it is now a Replication Controller. ([#30080](https://github.com/kubernetes/kubernetes/pull/30080), [@jszczepkowski](https://github.com/jszczepkowski))

- The `build-tag` flag is reintroduced to conversion-gen and defaulter-gen which allow users to inject custom build tag during code generation process. ([#128259](https://github.com/kubernetes/kubernetes/pull/128259), [@dinhxuanvu](https://github.com/dinhxuanvu))

- Kube-apiserver: Previously persisted `CustomResourceDefinition` objects with an invalid whitespace-only `caBundle` could serve requests that did not require conversion. ([#132514](https://github.com/kubernetes/kubernetes/pull/132514), [@tiffanny29631](https://github.com/tiffanny29631))

### Feature

- Parallelize calls to conversion webhooks when watching from etcd to prevent watchcache from lagging and helps clusters with slow conversion webhooks or transformers. 

* Add mechanism for Admission Webhooks to specify which version of AdmissionReview they support ([#74998](https://github.com/kubernetes/kubernetes/pull/74998), [@mbohlool](https://github.com/mbohlool))
    * Add mechanism for CRD Conversion Webhooks to specify which version of ConversionReview they support