containerMap is used in CPU Manager to store all containers information in the node.
containerMap provides a mapping from (pod, container) -> containerID for all containers a pod
It is reusable in another component in pkg/kubelet/cm which needs to track changes of all containers in the node.
Signed-off-by: Byonggon Chun <bg.chun@samsung.com>
This change is to prevent problems when we remove the V1->V2 migration
code in the future. Without this, the checksums of all checkpoints would
be hashed with the name CPUManagerCheckpointV2 embedded inside of them,
which is undesirable. We want the checkpoints to be hashed with the name
CPUManagerCheckpoint instead.
The updated CPUManager from PR #84462 implements logic to migrate the
CPUManager checkpoint file from an old format to a new one. To do so, it
defines the following types:
```
type CPUManagerCheckpoint = CPUManagerCheckpointV2
type CPUManagerCheckpointV1 struct { ... }
type CPUManagerCheckpointV2 struct { ... }
```
This replaces the old definition of just:
```
type CPUManagerCheckpoint struct { ... }
```
Code was put in place to ensure proper migration from checkpoints in V1
format to checkpoints in V2 format. However (and this is a big however),
all of the unit tests were performed on V1 checkpoints that were
generated using the type name `CPUManagerCheckpointV1` and not the
original type name of `CPUManagerCheckpoint`. As such, the checksum in
the checkpoint file uses the `CPUManagerCheckpointV1` type to calculate
its checksum and not the original type name of `CPUManagerCheckpoint`.
This causes problems in the real world since all pre-1.18 checkpoint
files will have been generated with the original type name of
`CPUManagerCheckpoint`. When verifying the checksum of the checkpoint
file across an upgrade to 1.18, the checksum is calculated assuming
a type name of `CPUManagerCheckpointV1` (which is incorrect) and the
file is seen to be corrupt.
This patch ensures that all V1 checksums are verified against a type
name of `CPUManagerCheckpoint` instead of ``CPUManagerCheckpointV1`.
It also locks the algorithm used to calculate the checksum in place,
since it wil never change in the future (for pre-1.18 checkpoint
files at least).
Previously, the state was keyed off of containerID intead of podUID and
containerName. Unfortunately, this is no longer possible as we move to a
to model where we we allocate CPUs to containers at pod adit time rather
than container start time.
This patch is the first step towards full migration to the new
semantics. Only the unit tests in cpumanager/state are passing. In
subsequent commits we will update the CPUManager itself to use these new
semantics.
This patch also includes code to do migration from the old checkpoint format
to the new one, assuming the existence of a ContainerMap with the proper
mapping of (containerID)->(podUID, containerName). A subsequent commit
will update code in higher layers to make sure that this ContainerMap is
made available to this state logic.
