kubernetes: Daemonsets pods are being scheduled with duplicate IPs

What happened: Pods are being scheduled with duplicate IPs

What you expected to happen: Unique IP per pods

How to reproduce it (as minimally and precisely as possible): No clue, it seems to happen randomly. I only noticed it when my errors rate went up, and one of my Nginx Ingress (daemonset) wasn’t reachable because of the IP conflict.

Most of the IP conflict remaining are bad but it seems like the cluster is still humming

kube-system     ip-masq-agent-wsqn5                                         1/1       Running     0          15h       172.20.1.10    gke-plr-web-prd-05-web-00-531bb1cd-2djt         <none>
kube-system     kube-proxy-gke-plr-web-prd-05-web-00-531bb1cd-2djt          1/1       Running     0          15h       172.20.1.10    gke-plr-web-prd-05-web-00-531bb1cd-2djt         <none>
monitoring      node-exporter-mz76k                                         1/1       Running     0          15h       172.20.1.10    gke-plr-web-prd-05-web-00-531bb1cd-2djt         <none>

Anything else we need to know?: I created a GKE cluster with a custom pod address range and VPC-Native on. It looks like a race condition thing because it seems to only happen to DaemonSets and system pods, and the conflict is all on the same node, and the pod all have the same age

Environment:

• Kubernetes version (use kubectl version):

Client Version: version.Info{Major:"1", Minor:"11", GitVersion:"v1.11.2", GitCommit:"bb9ffb1654d4a729bb4cec18ff088eacc153c239", GitTreeState:"clean", BuildDate:"2018-08-08T16:31:10Z", GoVersion:"go1.10.3", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"11+", GitVersion:"v1.11.2-gke.18", GitCommit:"5796233393d7bc034428de15191ad3d2eaff95fb", GitTreeState:"clean", BuildDate:"2018-11-08T20:49:08Z", GoVersion:"go1.10.3b4", Compiler:"gc", Platform:"linux/amd64"}

• Cloud provider or hardware configuration:

GKE

    Master version => 1.11.2-gke.18    
    Endpoint => <redacted>
    Client certificate	=> Enabled
    Binary authorization	=> Disabled
    Kubernetes alpha features	 => Disabled
    Current total size  => 33
    Master zone	=> us-west1-a
    Node zones	=> us-west1-a
    Network	 => <redacted>
    Subnet	=> <redacted>
    VPC-native (alias IP)	=> Enabled
    Pod address range	=> 172.30.0.0/17
    Default maximum pods per node	=> 110
    Service address range	=> 172.30.128.0/17
    Stackdriver Logging	 => Enabled
    Stackdriver Monitoring	=> Enabled
    Private cluster	=> Disabled
    Master authorized networks	=> Disabled
    Network policy	=> Disabled
    Legacy authorization	=> Disabled
    Maintenance window	=> 3:00 PM
    Cloud TPU	=> Disabled
    Node auto-provisioning	=> Disabled

• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

/kind bug