[Release 1.26] Difficult to filter netpol errors

[manuelbuil]

Backport: #7538

[bguzman-3pillar]

Validated on 88eb3ae

$ k3s -v
k3s version v1.26.4+k3s-88eb3ae5 (88eb3ae5)
go version go1.19.8

Environment Details

Infrastructure

• Cloud
• Hosted

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

$ cat /etc/os-release
PRETTY_NAME="Ubuntu 22.04.2 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.2 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy

Cluster Configuration:

1 server

Config.yaml:

write-kubeconfig-mode: 644
debug: true
token: verymanyoddbatteries
cluster-init: true
node-ip: TAILSCALE_IPV4,TAILSCALE_IPV6
cluster-cidr: 10.42.0.0/16,2001:cafe:42:0::/56
service-cidr: 10.43.0.0/16,2001:cafe:42:1::/112

Testing Steps

1. Install tailscale in the node: curl -fsSL https://tailscale.com/install.sh | sh. That will create a tailscale0 interface
2. execute tailscale up and login. That should give tailscale0 two IP addresses, one IPv4 and one IPv6
3. Deploy k3s with the config.yaml file
4. Replace $tailscale0_IPV4 and $tailscale0_IPV6 by the ip addresses of the tailscale0 interface
   After ~20 seconds, k3s installation will fail. You will see in the journalctl logs:
   level=fatal msg="IPv6 was enabled but no IPv6 address was found on node"

Validation Results:

$ journalctl -u k3s | grep "initialize Network Policy"
May 18 15:29:24 ip-192-168-25-141 k3s[7181]: time="2023-05-18T15:29:24Z" level=fatal msg="unable to initialize Network Policy Controller: IPv6 was enabled but no IPv6 address was found on node"
May 18 15:29:34 ip-192-168-25-141 k3s[7405]: time="2023-05-18T15:29:34Z" level=fatal msg="unable to initialize Network Policy Controller: IPv6 was enabled but no IPv6 address was found on node"
May 18 15:29:43 ip-192-168-25-141 k3s[7472]: time="2023-05-18T15:29:43Z" level=fatal msg="unable to initialize Network Policy Controller: IPv6 was enabled but no IPv6 address was found on node"
May 18 15:29:53 ip-192-168-25-141 k3s[7540]: time="2023-05-18T15:29:53Z" level=fatal msg="unable to initialize Network Policy Controller: IPv6 was enabled but no IPv6 address was found on node"