Syslog logging doesn't work in a dual-stack or IPv6-only cluster

[bootc]

In a dual-stack (or IPv6 only) cluster, localhost resolves to ::1. HAProxy is configured to log to localhost:514 and dutifully sends log messages to [::1]:514, but the whereisaaron/kube-syslog-sidecar listens only on the IPv4 0.0.0.0 address. Thus, the messages go nowhere:

10:01:39.195717 IP6 ::1.48755 > ::1.514: SYSLOG local0.info, length: 258
10:01:39.195739 IP6 ::1 > ::1: ICMP6, destination unreachable, unreachable port, ::1 udp port 514, length 314

A quick workaround for dual-stack clusters would be to change the localhost address to 127.0.0.1, but that wouldn't help IPv6-only clusters. Ideally the latter image would switch to using :: to listen, or have a configurable listen address.

Another potential workaround that I've just thought of is to use the "external" HAProxy, which can instead log to its own stdout. I'll give that a try and report back.

[bootc]

Another potential workaround that I've just thought of is to use the "external" HAProxy, which can instead log to its own stdout. I'll give that a try and report back.

Yep, this works fine.