This extends the Kubelet to create and periodically update leases in a
new kube-node-lease namespace. Based on [KEP-0009](https://github.com/kubernetes/community/blob/master/keps/sig-node/0009-node-heartbeat.md),
these leases can be used as a node health signal, and will allow us to
reduce the load caused by over-frequent node status reporting.
- add NodeLease feature gate
- add kube-node-lease system namespace for node leases
- add Kubelet option for lease duration
- add Kubelet-internal lease controller to create and update lease
- add e2e test for NodeLease feature
- modify node authorizer and node restriction admission controller
to allow Kubelets access to corresponding leases
The word 'manifest' technically refers to a container-group specification
that predated the Pod abstraction. We should avoid using this legacy
terminology where possible. Fortunately, the Kubelet's config API will
be beta in 1.10 for the first time, so we still had the chance to make
this change.
I left the flags alone, since they're deprecated anyway.
I changed a few var names in files I touched too, but this PR is the
just the first shot, not the whole campaign
(`git grep -i manifest | wc -l -> 1248`).
They should both follow the convention of not being a pointer on the
internal type. This required adding a conversion function between
`int64` and `*int64`.
A side effect is this removes a warning in the generated code for the
apps API group.
Add a new Alpha Feature to set a maximum number of pids per Pod.
This is to allow the use case where cluster administrators wish
to limit the pids consumed per pod (example when running a CI system).
By default, we do not set any maximum limit, If an administrator wants
to enable this, they should enable `SupportPodPidsLimit=true` in the
`--feature-gates=` parameter to kubelet and specify the limit using the
`--pod-max-pids` parameter.
The limit set is the total count of all processes running in all
containers in the pod.
