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>`.
When a host port conflict is detected, kubelet should set the pod status to
fail. The failed status will then be polled by other components at a later time,
which allows replication controller to create a new pod if necessary.
To achieve this, this change stores the pod status information in a status map
upon the detecton of port conflict. GetPodStatus() consults this status map
before attempting to query docker. The entries in the status map will be removed
when the pod is no longer associated with the node.
There are three values that uniquely identify a pod on a host -
the configuration source (etcd, file, http), the pod name, and the
pod namespace. This change ensures that configuration properly
makes those names unique by changing podFullName to contain both
name (currently ID in v1beta1, Name in v1beta3) and namespace.
The Kubelet does not properly handle information requests for
pods not in the default namespace at this time.
Yu-Ju Hong