[Release-1.27] - coredns, metrics, nginx and snapshot validation services are always singleStack

[manuelbuil]

Backport fix for coredns, metrics, nginx and snapshot validation services are always singleStack

• coredns, metrics, nginx and snapshot validation services are always singleStack #4776

[ShylajaDevadiga]

Validated using rke2 version v1.27.7-rc2+rke2r1

Environment Details

Infrastructure
Cloud EC2 instance

Node(s) CPU architecture, OS, and Version:
Ubuntu 22.04

Cluster Configuration:
3 server 1 agent

Config.yaml:

$ cat config.yaml 
node-ip: <IPv6>,<ipv4>
token: <TOKEN>
write-kubeconfig-mode: 644
cluster-cidr: 2001:cafe:42:0::/56,10.42.0.0/16
service-cidr: 2001:cafe:42:1::/112,10.43.0.0/16

Steps to reproduce the issue and validate the fix

1. Copy config.yaml
2. Install rke2

Validation results:
Services have ipv6 address, based on the order in node-ip flag in the config.yaml

$ kubectl get svc -A
NAMESPACE     NAME                                      TYPE        CLUSTER-IP             EXTERNAL-IP   PORT(S)         AGE
default       kubernetes                                ClusterIP   2001:cafe:42:1::1      <none>        443/TCP         24m
kube-system   rke2-coredns-rke2-coredns                 ClusterIP   2001:cafe:42:1::a      <none>        53/UDP,53/TCP   24m
kube-system   rke2-ingress-nginx-controller-admission   ClusterIP   2001:cafe:42:1::83ad   <none>        443/TCP         23m
kube-system   rke2-metrics-server                       ClusterIP   2001:cafe:42:1::6100   <none>        443/TCP         23m
kube-system   rke2-snapshot-validation-webhook          ClusterIP   2001:cafe:42:1::ff55   <none>        443/TCP         23m

Services have PreferDualStack in dualstack mode

$ kubectl describe svc -n kube-system    |grep  -i family -A4 -B2
Selector:          app.kubernetes.io/instance=rke2-coredns,app.kubernetes.io/name=rke2-coredns,k8s-app=kube-dns
Type:              ClusterIP
IP Family Policy:  PreferDualStack
IP Families:       IPv6,IPv4
IP:                2001:cafe:42:1::a
IPs:               2001:cafe:42:1::a,10.43.0.10
Port:              udp-53  53/UDP
--
Selector:          app.kubernetes.io/component=controller,app.kubernetes.io/instance=rke2-ingress-nginx,app.kubernetes.io/name=rke2-ingress-nginx
Type:              ClusterIP
IP Family Policy:  PreferDualStack
IP Families:       IPv6,IPv4
IP:                2001:cafe:42:1::83ad
IPs:               2001:cafe:42:1::83ad,10.43.117.25
Port:              https-webhook  443/TCP
--
Selector:          app=rke2-metrics-server,release=rke2-metrics-server
Type:              ClusterIP
IP Family Policy:  PreferDualStack
IP Families:       IPv6,IPv4
IP:                2001:cafe:42:1::6100
IPs:               2001:cafe:42:1::6100,10.43.152.54
Port:              <unset>  443/TCP
--
Selector:          app.kubernetes.io/instance=rke2-snapshot-validation-webhook,app.kubernetes.io/name=rke2-snapshot-validation-webhook
Type:              ClusterIP
IP Family Policy:  PreferDualStack
IP Families:       IPv6,IPv4
IP:                2001:cafe:42:1::ff55
IPs:               2001:cafe:42:1::ff55,10.43.187.33
Port:              https  443/TCP

Pods have ipv6 as well as ipv4 IP

$ kubectl describe pod -A |grep -i IPs -A3

...
IPs:
  IP:           <IPv6 REDACTED>
  IP:           192.168.21.37
Controlled By:  DaemonSet/rke2-canal
--
                      cni.projectcalico.org/podIPs: 10.42.0.5/32,2001:cafe:42::5/128
                      scheduler.alpha.kubernetes.io/tolerations: [{"key":"CriticalAddonsOnly", "operator":"Exists"}]
Status:               Running
IP:                   2001:cafe:42::5
IPs:
  IP:           2001:cafe:42::5
  IP:           10.42.0.5
Controlled By:  ReplicaSet/rke2-coredns-rke2-coredns-autoscaler-6f97df447
--
...

Validated pod to pod communication

$ kubectl exec -it multitool-deployment-755d68d775-2b9d7  bash
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
bash-5.1# ping 2001:cafe:42:3::3
PING 2001:cafe:42:3::3(2001:cafe:42:3::3) 56 data bytes
64 bytes from 2001:cafe:42:3::3: icmp_seq=1 ttl=62 time=0.502 ms
^C
--- 2001:cafe:42:3::3 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.502/0.502/0.502/0.000 ms
bash-5.1# ping 2001:cafe:42:2::4
PING 2001:cafe:42:2::4(2001:cafe:42:2::4) 56 data bytes
64 bytes from 2001:cafe:42:2::4: icmp_seq=1 ttl=62 time=0.719 ms
^C
--- 2001:cafe:42:2::4 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.719/0.719/0.719/0.000 ms
bash-5.1#