Container doesn't listen on IPv6

[SuperQ]

Summary

In a dual-stack Kubernetes environment the health checks default to probing via IPv6. The container nginx only listens on IPv4 by default.

[tiredofit/self-service-password 12:30:57 /] $ netstat -nltp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 0.0.0.0:9000            0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:73              0.0.0.0:*               LISTEN      3139/nginx: master 
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      3139/nginx: master 
tcp        0      0 :::8050                 :::*                    LISTEN      -
tcp        0      0 :::10050                :::*                    LISTEN      -

Steps to reproduce

From inside the container:

bash-5.1# curl http://[::1]:80/
curl: (7) Failed to connect to ::1 port 80 after 0 ms: Couldn't connect to server

What is the expected correct behavior?

Returns 200 OK.

Relevant logs and/or screenshots

Environment

Dual-Stack Kubernetes (k3s) using a helm chart:

https://github.com/jp-gouin/helm-openldap

• Image version / tag:
• Host OS: Debian

Possible fixes

Not sure if it's the correct solution, but adding listen [::]:80 ipv6only=off; to the nginx server config.