mc-probe

A small static binary to embed in Minecraft server container images, intended as Kubernetes liveness, readiness, and startup probes.

Probes

Probe	Check
startup	Ping status returns players.max > 0 (server has finished bootstrapping)
liveness	TCP dial only — listening socket is open (avoids false positives)
readiness	startup + players.online < players.max

Args

Arg	Default	Description
--host	127.0.0.1	Server host.
--port	25565	Server port.
--timeout	1s	Ping timeout.

K8s Usage

livenessProbe:
  exec:
    command: ["mcprobe", "liveness"]
  periodSeconds: 10
  failureThreshold: 3

readinessProbe:
  exec:
    command: ["mcprobe", "readiness"]
  periodSeconds: 2
  failureThreshold: 1

startupProbe:
  exec:
    command: ["mcprobe", "startup"]
  initialDelaySeconds: 30
  periodSeconds: 3
  failureThreshold: 100

readinessProbe.failureThreshold: 1 is intentional.

A failure only removes the pod from service endpoints (no restart), so flapping is cheap and load balancers can route around full instances immediately.