Because they need to prepare the hypervisor networking interfaces
and have them match the ones created in the pod networking
namespace (typically to bridge TAP and veth interfaces), hypervisor
based container runtimes need the sandbox pod networking namespace
to be set up before it's created. They can then prepare and start
the hypervisor interfaces when creating the pod virtual machine.
In order to do so, we need to create per pod persitent networking
namespaces that we pass to the CNI plugin. This patch leverages
the CNI ns package to create such namespaces under /var/run/netns,
and assign them to all pod containers.
The persitent namespace is removed when either the pod is stopped
or removed.
Since the StopPodSandbox() API can be called multiple times from
kubelet, we track the pod networking namespace state (closed or
not) so that we don't get a containernetworking/ns package error
when calling its Close() routine multiple times as well.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
And in particular make it not fail when removing an already removed
sandbox pod. According to the CRI spec:
[RemovePodSandbox] is idempotent, and must not return an error if
the sandbox has already been removed.
We now only print a warning instead of returning an error.
We still return an error when the passed pod ID is empty.
Fixes#240
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
