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FAQ

What NIC drivers and transceiver types are supported?

Any driver that implements the Linux ethtool module-info/module-EEPROM operations, and any pluggable optic form factor whose EEPROM layout wobcom/go-ethtool can parse (SFP, SFP+, SFP28, QSFP, QSFP+, QSFP28 and similar). There is no exporter-side allowlist of drivers or vendors — see Architecture and Troubleshooting.

Does it work on non-Linux hosts?

No. ethtool's SIOCETHTOOL ioctl interface is Linux-specific. Release binaries are built for linux/amd64 and linux/arm64 only — see Installation.

Why does it need CAP_NET_ADMIN just to read data?

SIOCETHTOOL ioctls (which cover both driver info and module EEPROM reads) require CAP_NET_ADMIN on this exporter's code path, even though the exporter itself only performs reads and never reconfigures an interface. See Permissions for how to grant only that capability rather than running the whole process as root.

Why does the container run as root?

The shipped image runs as root (UID 0) with all capabilities dropped except NET_ADMIN, rather than as a distroless non-root user with the capability added — an earlier revision tried the non-root approach and it broke EEPROM access, so it was reverted. See Permissions.

Can I run more than one instance against the same host?

There's no reason to — each instance would enumerate and read the same interfaces independently, duplicating series with no coordination between them (Prometheus would see two targets reporting the same interface label values). Run exactly one instance per host, on the host network.

Why is CAP_NET_ADMIN sufficient, but the container still uses --network host?

They cover different things. CAP_NET_ADMIN grants the capability to issue networking-related ioctls; --network host (or hostNetwork: true on Kubernetes) puts the container in the network namespace that actually contains the host's physical interfaces. Without the host network namespace, net.Interfaces() only sees the container's own virtual interfaces, no matter what capability the process holds. See Getting Started.

Does it support authentication on /metrics?

No — see Security. Restrict access at the network layer (firewall, reverse proxy, or a management-network bind).

Milliwatts or dBm — which should I use?

Milliwatts (the default) matches what the module reports natively, with no conversion or edge cases. dBm (-collector.optical-power-in-dbm) is more familiar for fiber-optic power budgets but converts a 0 mW reading to -Inf — see Troubleshooting before enabling it if your storage pipeline is picky about non-finite floats.

It's an independently maintained continuation of that project and its underlying wobcom/go-ethtool library — not a GitHub fork. See the project section on the home page for the full attribution and licensing note.