[Release-1.25] - 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 v1.26.10-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
Services have PreferDualStack as default
Pods have ipv6 as well as ipv4 address. kubectl displays it with ipv4 as mentioned here k3s-io/k3s#8598 (comment)

ubuntu@ip-192-168-28-30:~$ rke2 -v
rke2 version v1.25.15-rc3+rke2r1 (2ef1437e2223dc1f4c41bd52afde42e361d134aa)

go version go1.20.10 X:boringcrypto
ubuntu@ip-192-168-28-30:~$ 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         11m
kube-system   rke2-coredns-rke2-coredns                 ClusterIP   2001:cafe:42:1::a      <none>        53/UDP,53/TCP   10m
kube-system   rke2-ingress-nginx-controller-admission   ClusterIP   2001:cafe:42:1::396d   <none>        443/TCP         9m53s
kube-system   rke2-metrics-server                       ClusterIP   2001:cafe:42:1::ec38   <none>        443/TCP         10m
kube-system   rke2-snapshot-validation-webhook          ClusterIP   2001:cafe:42:1::a55d   <none>        443/TCP         10m

ubuntu@ip-192-168-28-30:~$ 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::396d
IPs:               2001:cafe:42:1::396d,10.43.108.127
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::ec38
IPs:               2001:cafe:42:1::ec38,10.43.19.222
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::a55d
IPs:               2001:cafe:42:1::a55d,10.43.119.229
Port:              https  443/TCP
ubuntu@ip-192-168-28-30:~$ 

 ubuntu@ip-192-168-28-30:~$ kubectl exec -it multitool-deployment-8487fd8b9f-k5xb7 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 10.42.2.3
PING 10.42.2.3 (10.42.2.3) 56(84) bytes of data.
64 bytes from 10.42.2.3: icmp_seq=1 ttl=62 time=1.01 ms
64 bytes from 10.42.2.3: icmp_seq=2 ttl=62 time=0.378 ms
^C
--- 10.42.2.3 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 0.378/0.693/1.008/0.315 ms
bash-5.1# ping 10.42.3.3
PING 10.42.3.3 (10.42.3.3) 56(84) bytes of data.
64 bytes from 10.42.3.3: icmp_seq=1 ttl=62 time=6.04 ms
^C
--- 10.42.3.3 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 6.041/6.041/6.041/0.000 ms
bash-5.1# ping 2001:cafe:42:4::3
PING 2001:cafe:42:4::3(2001:cafe:42:4::3) 56 data bytes
64 bytes from 2001:cafe:42:4::3: icmp_seq=1 ttl=62 time=0.435 ms
64 bytes from 2001:cafe:42:4::3: icmp_seq=2 ttl=62 time=0.371 ms
^C
--- 2001:cafe:42:4::3 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1022ms
rtt min/avg/max/mdev = 0.371/0.403/0.435/0.032 ms
bash-5.1#