fix: Update IPv6 routing rules for EKS clusters

The changes modify IPv6 routing configuration in Skipper deployment for
healthz endpoints. IPv6 LAN routes (fd00::/8 and ::1/128) are now only
included in non-EKS IPv6 environments, while EKS IPv6 configurations
properly use the subnet values from environment variables.

Author: ponimas

cluster/manifests/skipper/deployment.yaml

@@ -328,13 +328,13 @@ spec:
             kube__healthz_down:
             Path("/kube-system/healthz") &&
             Shutdown() &&
-            SourceFromLast("10.0.0.0/8", "192.168.0.0/16", "172.16.0.0/12", "127.0.0.1/8", "fd00::/8", "::1/128"{{- if and (eq .Cluster.Provider "zalando-eks") (eq .Cluster.ConfigItems.eks_ip_family "ipv6")}}{{ range $ip := split .Values.subnet_ipv6_cidrs "," }},"{{ $ip }}"{{ end }}{{- end }})
+            SourceFromLast("10.0.0.0/8", "192.168.0.0/16", "172.16.0.0/12", "127.0.0.1/8"{{- if and (eq .Cluster.Provider "zalando-eks") (eq .Cluster.ConfigItems.eks_ip_family "ipv6")}}{{ range $ip := split .Values.subnet_ipv6_cidrs "," }},"{{ $ip }}"{{ end }}{{- else }}, "fd00::/8", "::1/128"{{- end }})
             -> disableAccessLog()
             -> status(503)
             -> <shunt>;
             kube__healthz_up:
             Path("/kube-system/healthz") &&
-            SourceFromLast("10.0.0.0/8", "192.168.0.0/16", "172.16.0.0/12", "127.0.0.1/8", "fd00::/8", "::1/128"{{- if and (eq .Cluster.Provider "zalando-eks") (eq .Cluster.ConfigItems.eks_ip_family "ipv6")}}{{ range $ip := split .Values.subnet_ipv6_cidrs "," }},"{{ $ip }}"{{ end }}{{- end }})
+            SourceFromLast("10.0.0.0/8", "192.168.0.0/16", "172.16.0.0/12", "127.0.0.1/8"{{- if and (eq .Cluster.Provider "zalando-eks") (eq .Cluster.ConfigItems.eks_ip_family "ipv6")}}{{ range $ip := split .Values.subnet_ipv6_cidrs "," }},"{{ $ip }}"{{ end }}{{- else }}, "fd00::/8", "::1/128"{{- end }})
             -> disableAccessLog()
             -> status(200)
             -> <shunt>;