This previously caused a panic when moving lastKnownGood between two
non-nil values, because we were comparing the interface wrapper instead
of comparing the NodeConfigSources. The case of moving from one non-nil
lastKnownGood config to another doesn't appear to be tested by the e2e
node tests. I added a unit test and an e2e node test to help catch bugs
with this case in the future.
Automatic merge from submit-queue (batch tested with PRs 63881, 64046, 63409, 63402, 63221). 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>.
Kubelet responds to ConfigMap mutations for dynamic Kubelet config
This PR makes dynamic Kubelet config easier to reason about by leaving less room for silent skew scenarios. The new behavior is as follows:
- ConfigMap does not exist: Kubelet reports error status due to missing source
- ConfigMap is created: Kubelet starts using it
- ConfigMap is updated: Kubelet respects the update (but we discourage this pattern, in favor of incrementally migrating to a new ConfigMap)
- ConfigMap is deleted: Kubelet keeps using the config (non-disruptive), but reports error status due to missing source
- ConfigMap is recreated: Kubelet respects any updates (but, again, we discourage this pattern)
This PR also makes a small change to the config checkpoint file tree structure, because ResourceVersion is now taken into account when saving checkpoints. The new structure is as follows:
```
- dir named by --dynamic-config-dir (root for managing dynamic config)
| - meta
| - assigned (encoded kubeletconfig/v1beta1.SerializedNodeConfigSource object, indicating the assigned config)
| - last-known-good (encoded kubeletconfig/v1beta1.SerializedNodeConfigSource object, indicating the last-known-good config)
| - checkpoints
| - uid1 (dir for versions of object identified by uid1)
| - resourceVersion1 (dir for unpacked files from resourceVersion1)
| - ...
| - ...
```
fixes: #61643
```release-note
The dynamic Kubelet config feature will now update config in the event of a ConfigMap mutation, which reduces the chance for silent config skew. Only name, namespace, and kubeletConfigKey may now be set in Node.Spec.ConfigSource.ConfigMap. The least disruptive pattern for config management is still to create a new ConfigMap and incrementally roll out a new Node.Spec.ConfigSource.
```
This fixes an issue with KubeletConfiguration validation, where the
feature gates set by the new config were not taken into account.
Also fixes a validation issue with dynamic Kubelet config, where flag
precedence was not enforced prior to dynamic config validation in the
controller; this prevented rejection of dynamic configs that don't merge
well with values set via legacy flags.
Updates dynamic Kubelet config to use a structured status, rather than a
node condition. This makes the status machine-readable, and thus more
useful for config orchestration.
Fixes: #56896
This PR unpacks the downloaded ConfigMap to a set of files on the node.
This enables other config files to ride alongside the
KubeletConfiguration, and the KubeletConfiguration to refer to these
cohabitants with relative paths.
This PR also stops storing dynamic config metadata (e.g. current,
last-known-good config records) in the same directory as config
checkpoints. Instead, it splits the storage into `meta` and
`checkpoints` dirs.
This is a more accurate name for the condition, as it describes the
status of the Kubelet's configuration.
Also cleans up capitalization of internal names.
This changes the Kubelet configuration flag precedence order so that
flags take precedence over config from files/ConfigMaps.
See #56171 for rationale.
Note: Feature gates accumulate with the following
precedence (greater number overrides lesser number):
1. file-based config
2. dynamic cofig
3. flag-based config
Automatic merge from submit-queue (batch tested with PRs 57533, 57524). 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>.
Make ConfigOK status messages more human readable
This makes the ConfigOK status messages for dynamic config more human readable by including the path (e.g. SelfLink) to the object. The messages used to include the UID, but this was kind of useless, because there's no way to GET an object by UID.
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 57434, 57221, 57417, 57474, 57481). 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>.
Send an event just before the Kubelet restarts to use a new config
**What this PR does / why we need it**:
This PR makes the Kubelet send events for configuration changes. This makes it much easier to see a recent history of configuration changes for the Kubelet.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes#56895
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
/cc @dchen1107 @liggitt @dashpole
Rather than just changing the config once to see if dynamic kubelet
config at-least-sort-of-works, this extends the test to check that the
Kubelet reports the expected Node condition and the expected configuration
values after several possible state transitions.
Additionally, this adds a stress test that changes the configuration 100
times. It is possible for resource leaks across Kubelet restarts to
eventually prevent the Kubelet from restarting. For example, this test
revealed that cAdvisor's leaking journalctl processes (see:
https://github.com/google/cadvisor/issues/1725) could break dynamic
kubelet config. This test will help reveal these problems earlier.
This commit also makes better use of const strings and fixes a few bugs
that the new testing turned up.
Related issue: #50217
Automatic merge from submit-queue (batch tested with PRs 51805, 51725, 50925, 51474, 51638)
Flexvolume dynamic plugin discovery: Prober unit tests and basic e2e test.
**What this PR does / why we need it**: Tests for changes introduced in PR #50031 .
As part of the prober unit test, I mocked filesystem, filesystem watch, and Flexvolume plugin initialization.
Moved the filesystem event goroutine to watcher implementation.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#51147
**Special notes for your reviewer**:
First commit contains added functionality of the mock filesystem.
Second commit is the refactor for moving mock filesystem into a common util directory.
Third commit is the unit and e2e tests.
**Release note**:
```release-note
NONE
```
/release-note-none
/sig storage
/assign @saad-ali @liggitt
/cc @mtaufen @chakri-nelluri @wongma7
The subfeature was a cool idea, but in the end it is very complex to
separate Kubelet restarts into crash-loops caused by config vs.
crash-loops caused by other phenomena, like admin-triggered node restarts,
kernel panics, and and process babysitter behavior. Dynamic kubelet config
will be better off without the potential for false positives here.
Removing this subfeature also simplifies dynamic configuration by
reducing persistent state:
- we no longer need to track bad config in a file
- we no longer need to track kubelet startups in a file
This reverts commit f4afdecef8, reversing
changes made to e633a1604f.
This also fixes a bug where Kubemark was still using the core api scheme
to manipulate the Kubelet's types, which was the cause of the initial
revert.
Michael Taufen