Duplicate IP resulting from incorrect PID namespace

[BRONSOLO]

What you expected to happen?

weaver detects/claims pre-existing IPs attached to the weave bridge on node via

weave/prog/weaver/reclaim.go

Line 26 in 8c84763

func findExistingAddresses(dockerCli *weavedocker.Client, bridgeName string) (addrs []ipam.PreClaim, err error) {

What happened?

weaver stopped using the host process namespace (via hotsPID) as of #3876, which was needed for detecting devices via the peer ids / process ids here:

weave/prog/weaver/reclaim.go

Line 84 in 8c84763

netDevs, err := weavenet.GetNetDevsByVethPeerIds(pid, peerIDs)

.

Specifically, given the change of #3876, the following command only detects processes within the PID namespace of the weave-net pod:

weave/prog/weaver/reclaim.go

Line 79 in 8c84763

pids, err := common.AllPids("/proc")

How to reproduce it?

• Move the boltdb file so that the persisted data gets cleared
• Rotate the weave-net pod in the kube-system namespace
• Rotate any pod once the weave-net pod comes back up
• Notice how the IP assigned to the pod has already been assigned to another pod on the cluster

Anything else we need to know?

This is specifically for weave running on k8s.

Versions:

weave version 2.8.1