If a CRI error occurs during the terminating phase after a pod is
force deleted (API or static) then the housekeeping loop will not
deliver updates to the pod worker which prevents the pod's state
machine from progressing. The pod will remain in the terminating
phase but no further attempts to terminate or cleanup will occur
until the kubelet is restarted.
The pod worker now maintains a store of the pods state that it is
attempting to reconcile and uses that to resync unknown pods when
SyncKnownPods() is invoked, so that failures in sync methods for
unknown pods no longer hang forever.
The pod worker's store tracks desired updates and the last update
applied on podSyncStatuses. Each goroutine now synchronizes to
acquire the next work item, context, and whether the pod can start.
This synchronization moves the pending update to the stored last
update, which will ensure third parties accessing pod worker state
don't see updates before the pod worker begins synchronizing them.
As a consequence, the update channel becomes a simple notifier
(struct{}) so that SyncKnownPods can coordinate with the pod worker
to create a synthetic pending update for unknown pods (i.e. no one
besides the pod worker has data about those pods). Otherwise the
pending update info would be hidden inside the channel.
In order to properly track pending updates, we have to be very
careful not to mix RunningPods (which are calculated from the
container runtime and are missing all spec info) and config-
sourced pods. Update the pod worker to avoid using ToAPIPod()
and instead require the pod worker to directly use
update.Options.Pod or update.Options.RunningPod for the
correct methods. Add a new SyncTerminatingRuntimePod to prevent
accidental invocations of runtime only pod data.
Finally, fix SyncKnownPods to replay the last valid update for
undesired pods which drives the pod state machine towards
termination, and alter HandlePodCleanups to:
- terminate runtime pods that aren't known to the pod worker
- launch admitted pods that aren't known to the pod worker
Any started pods receive a replay until they reach the finished
state, and then are removed from the pod worker. When a desired
pod is detected as not being in the worker, the usual cause is
that the pod was deleted and recreated with the same UID (almost
always a static pod since API UID reuse is statistically
unlikely). This simplifies the previous restartable pod support.
We are careful to filter for active pods (those not already
terminal or those which have been previously rejected by
admission). We also force a refresh of the runtime cache to
ensure we don't see an older version of the state.
Future changes will allow other components that need to view the
pod worker's actual state (not the desired state the podManager
represents) to retrieve that info from the pod worker.
Several bugs in pod lifecycle have been undetectable at runtime
because the kubelet does not clearly describe the number of pods
in use. To better report, add the following metrics:
kubelet_desired_pods: Pods the pod manager sees
kubelet_active_pods: "Admitted" pods that gate new pods
kubelet_mirror_pods: Mirror pods the kubelet is tracking
kubelet_working_pods: Breakdown of pods from the last sync in
each phase, orphaned state, and static or not
kubelet_restarted_pods_total: A counter for pods that saw a
CREATE before the previous pod with the same UID was finished
kubelet_orphaned_runtime_pods_total: A counter for pods detected
at runtime that were not known to the kubelet. Will be
populated at Kubelet startup and should never be incremented
after.
Add a metric check to our e2e tests that verifies the values are
captured correctly during a serial test, and then verify them in
detail in unit tests.
Adds 23 series to the kubelet /metrics endpoint.
1. Core Kubelet changes to implement In-place Pod Vertical Scaling.
2. E2E tests for In-place Pod Vertical Scaling.
3. Refactor kubelet code and add missing tests (Derek's kubelet review)
4. Add a new hash over container fields without Resources field to allow feature gate toggling without restarting containers not using the feature.
5. Fix corner-case where resize A->B->A gets ignored
6. Add cgroup v2 support to pod resize E2E test.
KEP: /enhancements/keps/sig-node/1287-in-place-update-pod-resources
Co-authored-by: Chen Wang <Chen.Wang1@ibm.com>
The path module has a few different functions:
Clean, Split, Join, Ext, Dir, Base, IsAbs. These functions do not
take into account the OS-specific path separator, meaning that they
won't behave as intended on Windows.
For example, Dir is supposed to return all but the last element of the
path. For the path "C:\some\dir\somewhere", it is supposed to return
"C:\some\dir\", however, it returns ".".
Instead of these functions, the ones in filepath should be used instead.
In future commits we will need this to set the user/group of supported
volumes of KEP 127 - Phase 1.
Signed-off-by: Rodrigo Campos <rodrigoca@microsoft.com>
it is used to allocate and keep track of the unique users ranges
assigned to each pod that runs in a user namespace.
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Signed-off-by: Rodrigo Campos <rodrigoca@microsoft.com>
Co-authored-by: Rodrigo Campos <rodrigoca@microsoft.com>
The pod worker is the owner of when a container is running or not,
and the start and stop of the probes for a given pod should be
handled during the pod sync loop. This ensures that probes do not
continue running even after eviction.
Because the pod semantics allow lifecycle probes to shorten grace
period, the probe is removed after the containers in a pod are
terminated successfully. As an optimization, if the pod will have
a very short grace period (0 or 1 seconds) we stop the probes
immediately to reduce resource usage during eviction slightly.
After this change, the probe manager is only called by the pod
worker or by the reconcile loop.
* Add FeatureGate PodHostIPs
* Add HostIPs field and update PodIPs field
* Types conversion
* Add dropDisabledStatusFields
* Add HostIPs for kubelet
* Add fuzzer for PodStatus
* Add status.hostIPs in ConvertDownwardAPIFieldLabel
* Add status.hostIPs in validEnvDownwardAPIFieldPathExpressions
* Downward API support for status.hostIPs
* Add DownwardAPI validation for status.hostIPs
* Add e2e to check that hostIPs works
* Add e2e to check that Downward API works
* Regenerate
Other components must know when the Kubelet has released critical
resources for terminal pods. Do not set the phase in the apiserver
to terminal until all containers are stopped and cannot restart.
As a consequence of this change, the Kubelet must explicitly transition
a terminal pod to the terminating state in the pod worker which is
handled by returning a new isTerminal boolean from syncPod.
Finally, if a pod with init containers hasn't been initialized yet,
don't default container statuses or not yet attempted init containers
to the unknown failure state.
The field in fact says that the container runtime should relabel a volume
when running a container with it, it does not say that the volume supports
SELinux. For example, NFS can support SELinux, but we don't want NFS
volumes relabeled, because they can be shared among several Pods.
If CRI returns a container that has been created but is not running,
it is not safe to assume it is terminal, as our connection to CRI
may have failed. Instead, created is treated as waiting, as in
"waiting for this container to start". Either syncPod or
syncTerminatingPod is responsible for handling this state.
host-network pods IPs are obtained from the reported kubelet nodeIPs.
Historically, host-network podIPs are immutable once set, but when
we've added dual-stack support, we didn't consider that the secondary
IP address may not be present at the same time that the primary nodeIP.
If a secondary IP address is added to a node after the host-network pods
IPs are set, we can add the secondary host-network pod IP address
maintaining the current behavior of not updating the current podIPs on
host-network pods.
This patch makes the CRI `v1` API the new project-wide default version.
To allow backwards compatibility, a fallback to `v1alpha2` has been added
as well. This fallback can either used by automatically determined by
the kubelet.
Signed-off-by: Sascha Grunert <sgrunert@redhat.com>
The feature gate gets locked to "true", with the goal to remove it in two
releases.
All code now can assume that the feature is enabled. Tests for "feature
disabled" are no longer needed and get removed.
Some code wasn't using the new helper functions yet. That gets changed while
touching those lines.
The name concatenation and ownership check were originally considered small
enough to not warrant dedicated functions, but the intent of the code is more
readable with them.
When adding the ephemeral volume feature, the special case for
PersistentVolumeClaim volume sources in kubelet's host path and node
limits checks was overlooked. An ephemeral volume source is another
way of referencing a claim and has to be treated the same way.
Remove the VolumeSubpath feature gate.
Feature gate convention has been updated since this was introduced to
indicate that they "are intended to be deprecated and removed after a
feature becomes GA or is dropped.".
If a pod is killed (no longer wanted) and then a subsequent create/
add/update event is seen in the pod worker, assume that a pod UID
was reused (as it could be in static pods) and have the next
SyncKnownPods after the pod terminates remove the worker history so
that the config loop can restart the static pod, as well as return
to the caller the fact that this termination was not final.
The housekeeping loop then reconciles the desired state of the Kubelet
(pods in pod manager that are not in a terminal state, i.e. admitted
pods) with the pod worker by resubmitting those pods. This adds a
small amount of latency (2s) when a pod UID is reused and the pod
is terminated and restarted.
A pod that has been rejected by admission will have status manager
set the phase to Failed locally, which make take some time to
propagate to the apiserver. The rejected pod will be included in
admission until the apiserver propagates the change back, which
was an unintended regression when checking pod worker state as
authoritative.
A pod that is terminal in the API may still be consuming resources
on the system, so it should still be included in admission.
Fixes two issues with how the pod worker refactor calculated the
pods that admission could see (GetActivePods() and
filterOutTerminatedPods())
First, completed pods must be filtered from the "desired" state
for admission, which arguably should be happening earlier in
config. Exclude the two terminal pods states from GetActivePods()
Second, the previous check introduced with the pod worker lifecycle
ownership changes was subtly wrong for the admission use case.
Admission has to include pods that haven't yet hit the pod worker,
which CouldHaveRunningContainers was filtering out (because the
pod worker hasn't seen them). Introduce a weaker check -
IsPodKnownTerminated() - that returns true only if the pod is in
a known terminated state (no running containers AND known to pod
worker). This weaker check may only be called from components that
need admitted pods, not other kubelet subsystems.
This commit does not fix the long standing bug that force deleted
pods are omitted from admission checks, which must be fixed by
having GetActivePods() also include pods "still terminating".
