dd9917ddce fixed one test which did not wait for
pods to be deleted and then, depending on the timing, left ResourceClaims
prepared because the driver stopped before kubelet could call
NodeUnprepareResources.
But this is a more systematic issue also with other tests, so now the any test
which starts a DRA plugin automatically uses the same common cleanup code:
- delete pods in the test names
- wait for the driver to not have any active ResourceClaims
- stop the driver
Currently volume and dynamic-resource plugin shares an AssumeCache
implementation. However, they features significantly different use case. DRA
call Assume() on objects returned by APIServer, but volume call Assume() on
objects yet to be sent to the APIServer.
VolumeBinding plugin only makes one update request, while DynamicResource makes
2 requests (add finalizer then update allocation status). Taking advantage of
this, currently the volume cache is simpler:
1. Reserve: assume PV/PVC will be updated
2. PreBind: really send the update request
3. AssumeCache receives an update from informer and overwrite the assumed state.
a. if Prebind succeeded, this will surely include the update from step 2.
b. if PreBind is not finished yet, and this is an irrelevant update, it is safe to
overwrite the assumed state, because our update in PreBind will surely fail with Conflict.
While for DynamicResource:
1. Reserve: add devices to inFlightAllocations
2. PreBind:
a. send the 2 update requests
b. add the returned object into AssumeCache
c. AssumeCache dispatch events synchronously to update allocatedDevices
d. remove devices from inFlightAllocations
DynamicResource needs some features from AssumeCache that is not necessary for VolumeBinding:
1. DynamicResource needs strictly ordered update events to update allocatedDevices,
including those from Assume() and Restore()
2. DynamicResource needs to compare ResourceVersion to prevent the assumed state from being
overwritten by older version from informer. While this works, the doc[1] says:
"you must not compare resource versions for greater-than or less-than relationships".
Given so much difference, it can be beneficial to fork another simpler
AssumeCache for VolumeBinding plugin. Because of no need to send events, the
lite AssumeCache is a passive component. It only record the assumed version
without copying all objects from informer into its local cache. When reading,
we read from both informer and local cache. So it will always be up-to-date
with informer, no need to wait for event handler.
This resolves a race condition where AssumeCache and scheduler queue both
receive events from informer. When a pod is scheduling due to PV update event,
the PVCache may be not updated yet because it has not processed the relevant
event.
The passive version still listens events from informer, but only for cleaning up
its local cache to save memory.
[1]: https://kubernetes.io/docs/reference/using-api/api-concepts/#resource-versions
When building some command dynamically through KUBE_CGO_OVERRIDES, the base
image for that command must provide a libc which matches what the command was
compiled against. If the runtime libc is too old, then it might not have the
right ABI (missing symbols or wrong version of those symbols).
A user or job shouldn't need to know which of the different Kubernetes images
is the right one, therefore the build scripts now use the same image that was
previously only used for kube-proxy also for other commands if they get build
dynamically. This does not increase the maintenance effort because a single
image bump remains sufficient and for e.g. a kind cluster it doesn't matter
that the kube-proxy base image is slightly larger than necessary for the other
commands - it only needs to be present once in the node image.
updating to include initialization in func
Update store to use sets.Set
updating tests to use sets.New instead of sets.NewString
update store_test
update index_test
update controller_test file
update delta_fifo file
update expiration_cache_fakes file
update index_test file
update thread_safe_store file
update events_cache file
update thread_safe_store_test
update expiration_cache_test
small refactor of for loop
unexport the Index type -> index
The startup phase may have allocated memory that can be garbage-collected.
Forcing GC to run before measurements avoids noise if the garbage collection
kicks in during the measurement and potentially reduces the heap size reported
by metrics.
The exact effect has not been measured, it just seems useful.
