We had another bug where we confused the hostname with the NodeName.
To avoid this happening again, and to make the code more
self-documenting, we use types.NodeName (a typedef alias for string)
whenever we are referring to the Node.Name.
A tedious but mechanical commit therefore, to change all uses of the
node name to use types.NodeName
Also clean up some of the (many) places where the NodeName is referred
to as a hostname (not true on AWS), or an instanceID (not true on GCE),
etc.
pkg/service:
There were a couple of references here just as a reminder to change the
behavior of findPort. As of v1beta3, TargetPort was always defaulted, so
we could remove findDefaultPort and related tests.
pkg/apiserver:
The tests were using versioned API codecs for some of their encoding
tests. Necessary API types had to be written and registered with the
fake versioned codecs.
pkg/kubectl:
Some tests were converted to current versions where it made sense.
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>`.
Hostname behavior across operating systems is inconsistent (Macs can
have uppercase host names, so can some other systems). In general,
always strings.ToLower(os.Hostname()).
There are two main goals for this change.
1. Fix the naming scheme in kubelet so that it accepts DNS subdomain
name/namespaces correctly (#4920). The design is discussed in #3453.
2. Prepare for syncing the static pods back to the apiserver(#4090). This
includes
- Eliminate the source component in the internal full pod name (#4922). Pods
no longer need sources as they will all be sync'd via apiserver.
- Changing the naming scheme for the static (file-, http-, and etcd-based)
pods such that they are distinguishable when syncing back to the apiserver.
The changes includes:
* name = <pod.Name>-<hostname>
* namespace = <cluster_namespace> (i.e. "default" for now).
* container_name = k8s_<contianer_name>.<hash_of_container>_<pod_name>_<namespace>_<uid>_<random>
Note that this is not backward-compatible, meaning the kubelet won't recognize
existing running containers using the old naming scheme.
Make all kubelet config sources ensure that UID and Namespace are defaulted, if
need be.
We can *almost* disable the "if blank" logic for UID, except for tests that
call APIs that do not run through SyncPods. We really ought to be enforcing
invariants better.
stewart-yu