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Docker Container Health Check and Auto-Restart Shell Script

· dinesh
docker health check shell script

Keep Docker stacks running with a container health check script — detects stopped or unhealthy containers and restarts them automatically.

What this script does

  • Checks running state of named containers
  • Reads Docker health status (healthy/unhealthy)
  • Restarts failed containers with docker start/restart
  • Optional email alert when restart occurs
  • Logs all actions for post-incident review

Prerequisites

  • Docker installed and running
  • Containers with known names
  • Optional: mail for alerts

Step 1: Save the script

sudo nano /usr/local/bin/docker-health.sh
sudo chmod +x /usr/local/bin/docker-health.sh

Step 2: Full script (scroll to read)

docker-health.sh
#!/usr/bin/env bash
set -euo pipefail

CONTAINERS="nginx web app_db redis"
COMPOSE_DIR=""               # e.g. /opt/myapp — leave empty to skip compose
ALERT_EMAIL="[email protected]"
LOG="/var/log/docker-health.log"

log(){ echo "[$(date '+%F %T')] $*" | tee -a "$LOG"; }
alert(){ [[ -n "$ALERT_EMAIL" ]] && command -v mail >/dev/null && echo "$1" | mail -s "Docker alert: $(hostname -s)" "$ALERT_EMAIL" || true; }

ISSUES=0
for c in $CONTAINERS; do
  STATE=$(docker inspect -f '{{.State.Status}}' "$c" 2>/dev/null || echo "missing")
  HEALTH=$(docker inspect -f '{{if .State.Health}}{{.State.Health.Status}}{{else}}none{{end}}' "$c" 2>/dev/null || echo "missing")

  if [[ "$STATE" != "running" ]]; then
    log "Container $c is $STATE — restarting"
    docker start "$c" 2>/dev/null || docker restart "$c" 2>/dev/null || ISSUES=$((ISSUES+1))
    alert "Container $c was $STATE and was restarted on $(hostname -s)"
  elif [[ "$HEALTH" == "unhealthy" ]]; then
    log "Container $c is unhealthy — restarting"
    docker restart "$c"
    alert "Container $c was unhealthy and restarted on $(hostname -s)"
  else
    log "OK: $c ($STATE, health=$HEALTH)"
  fi
done

if [[ -n "$COMPOSE_DIR" && $ISSUES -gt 0 ]]; then
  log "Attempting docker compose up in $COMPOSE_DIR"
  (cd "$COMPOSE_DIR" && docker compose up -d) >> "$LOG" 2>&1
fi

exit $ISSUES

Scroll inside the box to read the full script.

Step 3: Configure settings

  • CONTAINERS — space-separated list of container names
  • COMPOSE_DIR — optional path to run docker compose up -d
  • ALERT_EMAIL — notify on restart events
Docker container health check shell script Linux
Docker container health check shell script Linux

Step 4: Test manually

docker ps -a
sudo /usr/local/bin/docker-health.sh

Schedule with cron

sudo crontab -e

Add:

*/5 * * * * /usr/local/bin/docker-health.sh >> /var/log/docker-health.log 2>&1

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Terminal screenshot is an original illustration created for Gnome IT Solutions (blog.gnomeitsolutions.com).