Docker Container/Daemon Health Check

Slug

KDCTR4D6HBTB

Fetches

0

Size

3306 B · 130 lines

Expires

never

Last fetch

—

Created

2026-09-07 00:35:58.870

Description

Daemon reachability, unhealthy containers, and disk use

#!/usr/bin/env bash
# Docker Container / Daemon Health Check
# Read-only report of daemon reachability, container state, and disk use.
# Exit 0 if healthy, 1 if warnings, 2 if the daemon is down or a container is unhealthy.
# Hosted on Runny.sh. Review the script page before you run it.

set -u

status=0
warns=0
crits=0

note() {
  printf '%s\n' "$*"
}

bump() {
  case $1 in
    crit)
      crits=$((crits + 1))
      status=2
      ;;
    warn)
      warns=$((warns + 1))
      if [ "$status" -lt 1 ]; then
        status=1
      fi
      ;;
  esac
}

note "=== Docker daemon and container health ==="
if ! command -v docker >/dev/null 2>&1; then
  note "docker:   CLI not found in PATH"
  note "Result:   CRITICAL"
  exit 2
fi

note "Client:   $(docker version --format '{{.Client.Version}}' 2>/dev/null || printf unknown)"
note ""

if ! docker info >/dev/null 2>&1; then
  note "Daemon:   unreachable"
  note "          Is the service running, and can this user talk to the socket?"
  note "Result:   CRITICAL"
  exit 2
fi

server=$(docker info --format '{{.ServerVersion}}' 2>/dev/null || printf unknown)
driver=$(docker info --format '{{.Driver}}' 2>/dev/null || printf unknown)
root=$(docker info --format '{{.DockerRootDir}}' 2>/dev/null || printf unknown)
note "Daemon:   ${server}  driver ${driver}"
note "Root:     ${root}"
note "          OK"
note ""

running=$(docker ps -q 2>/dev/null | awk 'END { print NR }')
total=$(docker ps -aq 2>/dev/null | awk 'END { print NR }')
note "Containers: ${running} running / ${total} total"

unhealthy=$(docker ps --filter health=unhealthy --format '{{.Names}} {{.Status}}' 2>/dev/null || true)
if [ -n "${unhealthy}" ]; then
  note "Unhealthy:"
  printf '%s\n' "$unhealthy" | while IFS= read -r row; do
    [ -n "$row" ] && note "  - ${row}"
  done
  bump crit
else
  note "Unhealthy: none"
fi

restarting=$(docker ps --filter status=restarting --format '{{.Names}} {{.Status}}' 2>/dev/null || true)
if [ -n "${restarting}" ]; then
  note "Restarting:"
  printf '%s\n' "$restarting" | while IFS= read -r row; do
    [ -n "$row" ] && note "  - ${row}"
  done
  bump crit
fi

dead=$(docker ps --filter status=dead --format '{{.Names}} {{.Status}}' 2>/dev/null || true)
if [ -n "${dead}" ]; then
  note "Dead:"
  printf '%s\n' "$dead" | while IFS= read -r row; do
    [ -n "$row" ] && note "  - ${row}"
  done
  bump crit
fi

exited_bad=$(docker ps -a --filter status=exited --format '{{.Names}} {{.Status}}' 2>/dev/null | awk '$0 ~ /Exited \([1-9]/ {print}' || true)
if [ -n "${exited_bad}" ]; then
  note "Exited with error:"
  count=0
  while IFS= read -r row; do
    [ -z "$row" ] && continue
    count=$((count + 1))
    if [ "$count" -le 8 ]; then
      note "  - ${row}"
    fi
  done <<EOF
${exited_bad}
EOF
  if [ "$count" -gt 8 ]; then
    note "  ... $((count - 8)) more"
  fi
  bump warn
fi
note ""

note "Disk (docker system df):"
if docker system df >/dev/null 2>&1; then
  docker system df | while IFS= read -r row; do
    note "  ${row}"
  done
else
  note "  could not read docker system df"
  bump warn
fi
note ""

if [ "$status" -eq 0 ]; then
  note "Result:   HEALTHY"
elif [ "$status" -eq 1 ]; then
  note "Result:   WARNING (${warns} check(s))"
else
  note "Result:   CRITICAL (${crits} critical, ${warns} warning)"
fi

exit "$status"