Confusing log when deploying dualStack

[manuelbuil]

Environmental Info:
K3s Version:

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

Cluster Configuration:

Describe the bug:

When running dualStack you get the log:

level=info msg="The interface eth0 with ipv4 address 10.1.1.10 will be used by flannel"

Which can be confusing, especially if you are prioritizing IPv6 family.

Steps To Reproduce:

• Installed K3s:

Deploy k3s in dualStack mode and check the logs

Expected behavior:

One log entry with both ip addresses

Actual behavior:

Two different log entries, one for IPv4 and one for IPv6

Additional context / logs:

[mdrahman-suse]

Pending fix: #8901
I was able to partially replicate and validate but need the above resolved to complete validation

[manuelbuil]

Pending fix: #8901 I was able to partially replicate and validate but need the above resolved to complete validation

The log does not really depend on the external IP IPFamily or?

[mdrahman-suse]

Validated on master branch with commit 96ebb96

Environment Details

Infrastructure

• Cloud
• Hosted

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

Linux 5.19.0-1025-aws #26~22.04.1-Ubuntu SMP Mon Apr 24 01:58:15 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
PRETTY_NAME="Ubuntu 22.04.2 LTS"
VERSION_ID="22.04"

Cluster Configuration:

1 server

Config.yaml:

write-kubeconfig-mode: "0644"
tls-san:
  - fake.fqdn.value
cluster-init: true
node-name: ip-xxx-xxx-xx-244.us-west-1.compute.internal
cluster-cidr: 2001:cafe:42:0::/56,10.42.0.0/16
service-cidr: 2001:cafe:43:0::/112,10.43.0.0/16
token: <token>
node-ip: <IPv6>,<PRIVATE IPv4>

Testing Steps

1. Copy config.yaml

$ sudo mkdir -p /etc/rancher/k3s && sudo cp config.yaml /etc/rancher/k3s

2. Install k3s
3. Check logs for the info
4. Should show both ipv4 and ipv6 IPs in the log in case of dual-stack

Replication Results:

• k3s version used for replication:

k3s version v1.28.3+k3s2 (bbafb86e)
go version go1.20.10

sudo journalctl -u k3s | grep -i interface
Nov 21 15:35:39 ip-xxx-xxx-xx-244 k3s[1895]: time="2023-11-21T15:35:39Z" level=info msg="The interface ens5 with ipv4 address <PRIVATE IPv4> will be used by flannel"

Validation Results:

• k3s version used for validation:

k3s version v1.28.3+k3s-96ebb963 (96ebb963)
go version go1.20.10

$ sudo journalctl -u k3s | grep -i interface
Nov 21 17:40:40 ip-xxx-xxx-xx-244 k3s[11438]: time="2023-11-21T17:40:40Z" level=info msg="Using dual-stack mode. The interface ens5 with ipv4 address <PRIVATE IPv4> and ipv6 address <IPv6> will be used by flannel"