To preserve the existing code base, we embed the new type within
the KubernetesIPAM (old type).

In a follow-up commit, this new struct will be used on a separate
golang binary (which doesn't require the KubernetesIPAM
configuration), to provide a simple connection to the Kubernetes
backend (does not support etcd).

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Fow now, we only read the kubeconfig file, which is specified via
the cmd line - as its only argument.

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Introduce a dedicated constructor in the storage pkg to create the
newly created `KubernetesClient` struct. The existing
`KubernetesIPAM` struct will re-use this new constructor.

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Follow-up commits will use this new method for debugging, which
makes it simpler to track the IP to pod assignments.

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Currently, matching the owner of the IP when deallocating the
address happens only based on the containerID.

In follow-up commits we will require this behavior to happen based
on the pod reference attribute.

This commit prepares the code base for that, by enabling the caller
to inject the criteria for identifying the owner of an IP into the
IP address de-allocation function.

Signed-off-by: Miguel Duarte Barroso <[email protected]>

This behavior will be encapsulated in a new struct named
`ReconcileLooper`, which features methods for:
  - CancelContext; cancels the current execution context
  - FindOrphanedIPsPerPool; returns a list of the orphaned
    IP addresses, indexed by pool
  - ReconcileIPPool; receives a list of orphaned IP
    addresses, and cleans them up from the respective pools
    where they are currently allocated.

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Signed-off-by: Miguel Duarte Barroso <[email protected]>

The service account for whereabouts requires the ability of
listing the pods on all namespaces, so it can check which ones
feature orphaned IPs.

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Only mark a pod as "alive" when the pod's annotations feature the
IP being de-allocated.

This makes the reconciler binary *dependent* on multus, which adds
these `network-status` annotations into the pod.

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Signed-off-by: Miguel Duarte Barroso <[email protected]>

By not returning an `IPReservation` entry - we now return an IP
address instead - we simplify the code.

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Signed-off-by: Miguel Duarte Barroso <[email protected]>

Signed-off-by: Miguel Duarte Barroso <[email protected]>

This commit changes the reconciler logic to only parse the
network-status annotations of whereabouts pods - e.g. pods whose
pod referecences (<namespace>/<pod name>) feature in any of the
whereabouts IPPools.

Signed-off-by: Miguel Duarte Barroso <[email protected]>