Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Introduce new `VolumeAttachment` API Object
**What this PR does / why we need it**:
Introduce a new `VolumeAttachment` API Object. This object will be used by the CSI volume plugin to enable external attachers (see design [here](https://github.com/kubernetes/community/pull/1258). In the future, existing volume plugins can be refactored to use this object as well.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: Part of issue https://github.com/kubernetes/features/issues/178
**Special notes for your reviewer**:
None
**Release note**:
```release-note
NONE
```
Moved client and kubeconfig related code to webhook/config;
Moved the rule matcher to webhook/rules;
Left TODOs saying we are going to move some other common utilities;
Other code is moved to webhook/validation.
The current registration of admission plug-ins happen too late so the
command line help is not yielding correct/useful information to users.
This is already causing confusion as mentioned in some issues.
This patch fixes it by moving plugins.go down to options package because
"plugins" in this context are themselves options for users. Registration
of plugins is not an expensive operation and it is already done in most
execution paths.
In future, we may want to revisit these plugins and migrate them to the
shared apiserver repo when appropriate.
Automatic merge from submit-queue
Add Priority admission controller
**What this PR does / why we need it**: Add Priority admission controller. This admission controller checks creation and update of PriorityClasses. It also resolves a PriorityClass name of a pod to its integer value.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
Add Priority admission controller for monitoring and resolving PriorityClasses.
```
ref/ #47604
ref/ #48646
Automatic merge from submit-queue (batch tested with PRs 49989, 49806, 49649, 49412, 49512)
This adds an etcd health check endpoint to kube-apiserver
addressing https://github.com/kubernetes/kubernetes/issues/48215.
**What this PR does / why we need it**:
This ensures kube-apiserver `/healthz` endpoint fails whenever connectivity cannot be established to etcd, also ensures the etcd preflight checks works with unix sockets
**Which issue this PR fixes**: fixes#48215
**Special notes for your reviewer**:
This PR does not use the etcd client directly as the client object is wrapped behind the storage interface and not exposed directly for use, so I decided to reuse what's being done in the preflight. So this will only check fail for connectivity and not etcd auth related problems. I did not write tests for the endpoint because I couldn't find examples that I could follow for writing tests for healthz related endpoints, I'll be willing to write those tests if someone can point me at a relevant one.
**Release note**:
```release-note
Add etcd connectivity endpoint to healthz
```
@deads2k please help review, thanks!
Automatic merge from submit-queue (batch tested with PRs 46718, 46828, 46988)
Simply changed the names of packages of some admission plugins.
**What this PR does / why we need it**:
This PR simply changes the names of packages of some admission plugins so that they are not in conflict with admission pkg.
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 46550, 46663, 46816, 46820, 46460)
Add configuration for encryption providers
## Additions
Allows providing a configuration file (using flag `--experimental-encryption-provider-config`) to use the existing AEAD transformer (with multiple keys) by composing mutable transformer, prefix transformer (for parsing providerId), another prefix transformer (for parsing keyId), and AES-GCM transformers (one for each key). Multiple providers can be configured using the configuration file.
Example configuration:
```
kind: EncryptionConfig
apiVersion: v1
resources:
- resources:
- namespaces
providers:
- aes:
keys:
- name: key1
secret: c2vjcmv0iglzihnly3vyzq==
- name: key2
secret: dghpcybpcybwyxnzd29yza==
- identity: {}
```
Need for configuration discussed in:
#41939
[Encryption](3418b4e4c6/contributors/design-proposals/encryption.md)
**Pathway of a read/write request**:
1. MutableTransformer
2. PrefixTransformer reads the provider-id, and passes the request further if that matches.
3. PrefixTransformer reads the key-id, and passes the request further if that matches.
4. GCMTransformer tries decrypting and authenticating the cipher text in case of reads. Similarly for writes.
## Caveats
1. To keep the command line parameter parsing independent of the individual transformer's configuration, we need to convert the configuration to an `interface{}` and manually parse it in the transformer. Suggestions on better ways to do this are welcome.
2. Flags `--encryption-provider` and `--encrypt-resource` (both mentioned in [this document](3418b4e4c6/contributors/design-proposals/encryption.md) ) are not supported in this because they do not allow more than one provider, and the current format for the configuration file possibly supersedes their functionality.
3. Currently, it can be tested by adding `--experimental-encryption-provider-config=config.yml` to `hack/local-up-cluster.sh` on line 511, and placing the above configuration in `config.yml` in the root project directory.
Previous discussion on these changes:
https://github.com/sakshamsharma/kubernetes/pull/1
@jcbsmpsn @destijl @smarterclayton
## TODO
1. Investigate if we need to store keys on disk (per [encryption.md](3418b4e4c6/contributors/design-proposals/encryption.md (option-1-simple-list-of-keys-on-disk)))
2. Look at [alpha flag conventions](https://github.com/kubernetes/kubernetes/blob/master/pkg/features/kube_features.go)
3. Need to reserve `k8s:enc` prefix formally for encrypted data. Else find a better way to detect transformed data.
Handle failure cases on startup gracefully to avoid causing cascading
errors and poor initialization in other components. Initial errors from
config load cause the initializer to pause and hold requests. Return
typed errors to better communicate failures to clients.
Add code to handle two specific cases - admin wants to bypass
initialization defaulting, and mirror pods (which want to bypass
initialization because the kubelet owns their lifecycle).
Automatic merge from submit-queue (batch tested with PRs 36721, 46483, 45500, 46724, 46036)
stop special casing the loopback connection for aggregator
Fixes a TODO for the aggregator loopback connection.
Automatic merge from submit-queue
Add initializer support to admission and uninitialized filtering to rest storage
Initializers are the opposite of finalizers - they allow API clients to react to object creation and populate fields prior to other clients seeing them.
High level description:
1. Add `metadata.initializers` field to all objects
2. By default, filter objects with > 0 initializers from LIST and WATCH to preserve legacy client behavior (known as partially-initialized objects)
3. Add an admission controller that populates .initializer values per type, and denies mutation of initializers except by certain privilege levels (you must have the `initialize` verb on a resource)
4. Allow partially-initialized objects to be viewed via LIST and WATCH for initializer types
5. When creating objects, the object is "held" by the server until the initializers list is empty
6. Allow some creators to bypass initialization (set initializers to `[]`), or to have the result returned immediately when the object is created.
The code here should be backwards compatible for all clients because they do not see partially initialized objects unless they GET the resource directly. The watch cache makes checking for partially initialized objects cheap. Some reflectors may need to change to ask for partially-initialized objects.
```release-note
Kubernetes resources, when the `Initializers` admission controller is enabled, can be initialized (defaulting or other additive functions) by other agents in the system prior to those resources being visible to other clients. An initialized resource is not visible to clients unless they request (for get, list, or watch) to see uninitialized resources with the `?includeUninitialized=true` query parameter. Once the initializers have completed the resource is then visible. Clients must have the the ability to perform the `initialize` action on a resource in order to modify it prior to initialization being completed.
```
Automatic merge from submit-queue (batch tested with PRs 46239, 46627, 46346, 46388, 46524)
Dynamic webhook admission control plugin
Unit tests pass.
Needs plumbing:
* [ ] service resolver (depends on @wfender PR)
* [x] client cert (depends on ????)
* [ ] hook source (depends on @caesarxuchao PR)
Also at least one thing will need to be renamed after Chao's PR merges.
```release-note
Allow remote admission controllers to be dynamically added and removed by administrators. External admission controllers make an HTTP POST containing details of the requested action which the service can approve or reject.
```
Add support for creating resources that are not immediately visible to
naive clients, but must first be initialized by one or more privileged
cluster agents. These controllers can mark the object as initialized,
allowing others to see them.
Permission to override initialization defaults or modify an initializing
object is limited per resource to a virtual subresource "RESOURCE/initialize"
via RBAC.
Initialization is currently alpha.
Add location transformer, config for transformers
Location transformer helps choose the most specific transformer for
read/write operations depending on the path of resource being accessed.
Configuration allows use of --experimental-encryption-provider-config
to set up encryption providers. Only AEAD is supported at the moment.
Add new files to BUILD, AEAD => k8s-aes-gcm
Use group resources to select encryption provider
Update tests for configuration parsing
Remove location transformer
Allow specifying providers per resource group in configuration
Add IdentityTransformer configuration option
Fix minor issues with initial AEAD implementation
Unified parsing of all configurations
Parse configuration using a union struct
Run configuration parsing in APIserver, refactor parsing
More gdoc, fix minor bugs
Add test coverage for combined transformers
Use table driven tests for encryptionconfig
Automatic merge from submit-queue (batch tested with PRs 46552, 46608, 46390, 46605, 46459)
Move admission lifecycle to genericapi
**What this PR does / why we need it**: ends the whole sequence of moving some admission plugins to generic api.
**Release note**:
```release-note
NONE
```
lifecycle plugin: make use of the libraries under k8s.io/client-go/pkg/api and k8s.io/client-go/kubernetes
for the client libraries instead of k8s.io/kubernetes/client/*
move registration to AdmissionOptions
Automatic merge from submit-queue (batch tested with PRs 45346, 45903, 45958, 46042, 45975)
ResourceQuota admission control injects registry
**What this PR does / why we need it**:
The `ResourceQuota` admission controller works with a registry that maps a GroupKind to an Evaluator. The registry used in the existing plug-in is not injectable, which makes usage of the ResourceQuota plug-in in other API server contexts difficult. This PR updates the code to support late injection of the registry via a plug-in initializer.
Chao Xu