Automatic merge from submit-queue (batch tested with PRs 45467, 48091, 48033, 48498)
Allow Kubenet with ipv6
When running kubenet with IPv6, there is a panic as there
is IPv4 specific code the Event function.
With this change, Event will support IPv4 and IPv6
**What this PR does / why we need it**:
This PR allows kubenet to use IPv6. Currently there is a panic in kubenet_linux.go
as there is IPv4 specific code.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#48089
**Special notes for your reviewer**:
**Release note**:
```release-note-NONE
```
Since v1.5 and the removal of --configure-cbr0:
0800df74ab "Remove the legacy networking mode --configure-cbr0"
kubelet hasn't done any shaping operations internally. They
have all been delegated to network plugins like kubenet or
external CNI plugins. But some shaping code was still left
in kubelet, so remove it now that it's unused.
MTU selection is difficult, and if there is a transport such as IPSEC in
use may be impossible. So we allow specification of the MTU with the
network-plugin-mtu flag, and we pass this down into the network
provider.
Currently implemented by kubenet.
Teardown can run before Setup when the kubelet is restarted... in that
case, the shaper was nil and thus calling the shaper resulted in a panic
This fixes that by ensuring the shaper is always set... +1 level of
indirection and all that.
Before this change, the podCIDRs map contained both cidrs and ips
depending on which code path entered a container into it.
Specifically, SetUpPod would enter a CIDR while GetPodNetworkStatus
would enter an IP.
This normalizes both of them to always enter just IP addresses.
This also removes the now-redundant cidr parsing that was used to get
the ip before
When the IP isn't in the internal map, GetPodNetworkStatus() needs
to call the execer for the 'nsenter' program. That means the execer
needs to be !nil, which it wasn't before.
