This change cleans up the pod manager extensively so that
* Mirror pods are actually stored in the pod manager.
* Both (non-mirror) pods and mirror pods are indexed by UID and full name for
easy lookup and mapping. This is required for the next change to send
full pod along with the pod status update.
This change also renames mirrorManager as mirrorClient since it is merely a
client to contact the API server and create/delete mirror pods.
This change moves pod array and mirrorPods into podManager, along with all
methods accessing these internal pod storages. This is the first step of the
refactoring, and no function change is involved.
Functions Build/ParseDockerName now work with struct instead of the long
list of arguments. This new struct also was reused in the kubelet.go
instead of auxilary podContainer struct.
Kubelet supports retrieving stats for pods/containers with and without UID.
This does not always work for the static pods because users may get the UIDs of
the mirror pods from the API server, and use them to query Kubelet. In this
case, Kubelet would fail to locate the containers due to mismatched UIDs.
This change adds a intenral mirror to static pod UID mapping and teaches all
public-facing functions to perform UID lookup before proceeding. This allows
users to use either mirror or static pod's UID to retrieve stats.
Per-pod worker syncs the pod and container status, and write the pod status in
the pod status cache. Given that it already owns a copy of the pod, it can
bypass the additional pod lookup step completely. This change adds a new
generatePodStatusByPod() method to achieve this. In general, per-pod worker
should avoid accessing the internal pod array completely, as this would may
lead to high contention.
This change also changes the return type of GetPodByFullName to reflect the
name, and consolidates GetPodByFullName() and GetPodByName().
Integrated the imageManager into the Kubelet and applies the garbage
collection policy every 5 minutes. The default policy allows up to 90%
disk usage, after which images are garbage collected to bring limit back
down to 80%.
Fixes#157.
Currently, API server is not aware of the static pods (manifests from
sources other than the API server, e.g. file and http) at all. This is
inconvenient since users cannot check the static pods through kubectl.
It is also sub-optimal because scheduler is unaware of the resource
consumption by these static pods on the node.
This change syncs the information back to the API server by creating a
mirror pod via API server for each static pod.
- Kubelet creates containers for the static pod, as it would do
normally.
- If a mirror pod gets deleted, Kubelet will re-create one. The
containers are sync'd to the static pods, so they will not be
affected.
- If a static pod gets removed from the source (e.g. manifest file
removed from the directory), the orphaned mirror pod will be deleted.
Note that because events are associated with UID, and the mirror pod has
a different UID than the original static pod, the events will not be
shown for the mirror pod when running `kubectl describe pod
<mirror_pod>`.
