Why It's Good to Exercise your Docker Containers (At Least Once a Day)..

This is the visual output of a number of containers.

• Each one was stopped and backed up then restarted. As it ran you can see the CPU RAM requirement significantly dropped!

A simple script as written by Grok 4 Expert can do this automatically daily.

#!/bin/bash

# Ensure script is run as root
if [ "$EUID" -ne 0 ]; then
  echo "This script must be run as root"
  exit 1
fi

# Get list of running container IDs
containers=$(docker ps -q)

# Check if there are any running containers
if [ -z "$containers" ]; then
  echo "No running containers found"
  exit 0
fi

# Iterate through each container
for container_id in $containers; do
  # Get container name for display
  container_name=$(docker inspect --format '{{.Name}}' "$container_id" | sed 's/^\///')

  echo "Processing container: $container_name ($container_id)"

  # Stop the container
  echo "Stopping container..."
  docker stop "$container_id"

  # Restart the container
  echo "Restarting container..."
  docker start "$container_id"

  echo "Container $container_name processed"
  echo "------------------------"
done

echo "All containers stopped and restarted"

The instructions to add this to cron are as follows:

To schedule the docker_stop_restart.sh script to run once a day via cron, you can add a cron job. Below, I'll provide instructions to set up the cron job and create a Task Schedule for the requested daily execution.

Instructions to Schedule the Script with Cron

Save the Script: Ensure the docker_stop_restart.sh script is saved, for example, at /usr/local/bin/docker_stop_restart.sh, and make it executable:

chmod +x /usr/local/bin/docker_stop_restart.sh

Edit the Crontab: Open the crontab file for the root user (since the script requires root privileges):

sudo crontab -e

Add the Cron Job: Add a line to schedule the script to run daily at a specific time, e.g., 2:00 AM. Use the following format:

0 2 * * * /usr/local/bin/docker_stop_restart.sh >> /var/log/docker_stop_restart.log 2>&1

• 0 2 * * *: Runs the script daily at 2:00 AM.
• >> /var/log/docker_stop_restart.log 2>&1: Logs output and errors to a file for troubleshooting.

Save and Exit: Save the crontab file (e.g., in vi, press :wq and Enter).

Verify the Cron Job: Check that the cron job is set up correctly:

sudo crontab -l

Ensure Cron is Running: Verify that the cron service is active:

sudo systemctl status cron

If it’s not running, start it:

sudo systemctl start cron
sudo systemctl enable cron

Task Schedule

Here’s the Task Schedule to reflect the daily execution of the script:

{
  "name": "Daily Docker Stop Restart",
  "prompt": "Run the docker_stop_restart.sh script to stop and restart each Docker container one at a time.",
  "cadence": "daily",
  "time_of_day": "02:00",
  "day_of_week": 1,
  "day_of_month": 1,
  "day_of_year": 1
}

Notes

• The script will run as root, matching the requirement in docker_stop_restart.sh.
• The log file (/var/log/docker_stop_restart.log) helps track execution and troubleshoot issues.
• Adjust the time_of_day in the Task Schedule or cron job to your preferred time.
• Ensure the script path in the cron job matches where you saved docker_stop_restart.sh.

Let me know if you need help with any part of this setup!