Dual stack on k3s with Klipper load balancer

[anon-software]

I cannot get dual stack configuration to work on k3s with servicelb (Klipper) to work. Here is the values file I used:

DNS1: 192.168.2.254
adminPassword: admin
dualStack:
  enabled: true
persistentVolumeClaim:
  enabled: true
  size: 100Mi
resources:
  limits:
    cpu: 200m
    memory: 256Mi
  requests:
    cpu: 100m
    memory: 128Mi
serviceDns:
  externalTrafficPolicy: Cluster
  type: LoadBalancer
serviceWeb:
  externalTrafficPolicy: Cluster
  http:
    port: "2080"
  https:
    port: "2443"
  type: LoadBalancer

This apparently creates two services, one for ipv4 and one for ipv6.

$ sudo kubectl get svc -n pihole
NAME                  TYPE           CLUSTER-IP           EXTERNAL-IP                                               PORT(S)                         AGE
pihole-dhcp           NodePort       10.43.225.145        <none>                                                    67:31286/UDP                    14m
pihole-dns-tcp        LoadBalancer   10.43.125.101        192.168.2.235,192.168.2.240,192.168.2.241,192.168.2.242   53:30891/TCP                    14m
pihole-dns-tcp-ipv6   LoadBalancer   2001:cafe:43::cde8   <pending>                                                 53:30509/TCP                    14m
pihole-dns-udp        LoadBalancer   10.43.227.133        192.168.2.235,192.168.2.240,192.168.2.241,192.168.2.242   53:30797/UDP                    14m
pihole-dns-udp-ipv6   LoadBalancer   2001:cafe:43::603a   <pending>                                                 53:31366/UDP                    14m
pihole-web            LoadBalancer   10.43.138.225        192.168.2.235,192.168.2.240,192.168.2.241,192.168.2.242   2080:31393/TCP,2443:31467/TCP   14m
pihole-web-ipv6       LoadBalancer   2001:cafe:43::661c   <pending>                                                 2080:31095/TCP,2443:32206/TCP   14m

As you can see above, only one service gets an external IP address. In this case it is always ipv4, but I think I have had ipv6 get the external IP address on occasion.

Klipper creates corresponding pods for these services.

$ sudo kubectl get pod -n kube-system|grep pihole
svclb-pihole-dns-tcp-eb679da4-55l7g        1/1     Running     0          18m
svclb-pihole-dns-tcp-eb679da4-5phpx        1/1     Running     0          18m
svclb-pihole-dns-tcp-eb679da4-clhp5        1/1     Running     0          18m
svclb-pihole-dns-tcp-eb679da4-fn7p7        1/1     Running     0          18m
svclb-pihole-dns-tcp-ipv6-1930b28c-46tfl   0/1     Pending     0          18m
svclb-pihole-dns-tcp-ipv6-1930b28c-dx456   0/1     Pending     0          18m
svclb-pihole-dns-tcp-ipv6-1930b28c-gtjtf   0/1     Pending     0          18m
svclb-pihole-dns-tcp-ipv6-1930b28c-r644b   0/1     Pending     0          18m
svclb-pihole-dns-udp-def81466-cc7c4        1/1     Running     0          18m
svclb-pihole-dns-udp-def81466-hbktg        1/1     Running     0          18m
svclb-pihole-dns-udp-def81466-mx5dr        1/1     Running     0          18m
svclb-pihole-dns-udp-def81466-sff7z        1/1     Running     0          18m
svclb-pihole-dns-udp-ipv6-7586bc32-5gl2q   0/1     Pending     0          18m
svclb-pihole-dns-udp-ipv6-7586bc32-cb7wn   0/1     Pending     0          18m
svclb-pihole-dns-udp-ipv6-7586bc32-dqm9l   0/1     Pending     0          18m
svclb-pihole-dns-udp-ipv6-7586bc32-qdq4v   0/1     Pending     0          18m
svclb-pihole-web-38f1c6a9-bxzkg            2/2     Running     0          18m
svclb-pihole-web-38f1c6a9-hn9tt            2/2     Running     0          18m
svclb-pihole-web-38f1c6a9-q26hp            2/2     Running     0          18m
svclb-pihole-web-38f1c6a9-w4h9q            2/2     Running     0          18m
svclb-pihole-web-ipv6-9b288549-4dkgq       0/2     Pending     0          18m
svclb-pihole-web-ipv6-9b288549-cs7zz       0/2     Pending     0          18m
svclb-pihole-web-ipv6-9b288549-jktgp       0/2     Pending     0          18m
svclb-pihole-web-ipv6-9b288549-rj4d8       0/2     Pending     0          18m

Drilling further into one of these pending pods, I can see this problem.

$ sudo kubectl describe pod -n kube-system svclb-pihole-web-ipv6-9b288549-4dkgq
[snip]
Events:
  Type     Reason            Age                  From               Message
  ----     ------            ----                 ----               -------
  Warning  FailedScheduling  20m                  default-scheduler  0/4 nodes are available: 1 node(s) didn't have free ports for the requested pod ports. preemption: 0/4 nodes are available: 1 node(s) didn't have free ports for the requested pod ports, 3 Preemption is not helpful for scheduling.
  Warning  FailedScheduling  4m21s (x3 over 14m)  default-scheduler  0/4 nodes are available: 1 node(s) didn't have free ports for the requested pod ports. preemption: 0/4 nodes are available: 1 node(s) didn't have free ports for the requested pod ports, 3 Preemption is not helpful for scheduling.

I think if we can have one service configured for dual stack, we would not have this problem.

[anon-software]

I found a related pull request, #202. After briefly testing it, it appears to have fixed my problem. It would be nice if you can merge it. In the meantime I shall use my forked repository.