Docker Container Crash Monitor 🚨

A simple but powerful bash script that monitors your Docker containers and sends Slack notifications when containers crash. Perfect for keeping tabs on your containers' health without constantly checking logs.

What does it do? 🤔

Ever had a Docker container silently die on you? Yeah, me too. That's why I built this. It sits quietly in the background watching your containers, and the moment one crashes - BAM! - you get a Slack notification with all the important details:

• Container name
• Container ID
• Image used
• Exit code
• How long it ran
• Which host it was running on

Setup Guide 🛠️

1. Get the files ready

First, let's get the monitoring script and service file where they need to be:

Create the monitor script:

# Create the script file
sudo nano /usr/local/bin/docker-monitor.sh

# Make it executable
sudo chmod +x /usr/local/bin/docker-monitor.sh

Create the service file:

sudo nano /etc/systemd/system/docker-monitor.service

Copy the contents from both files in this repo into these new files.

2. Set up your Slack webhook

1. Go to your Slack workspace
2. Create a new webhook (or use an existing one) at https://api.slack.com/apps
3. Copy the webhook URL
4. Replace the SLACK_WEBHOOK_URL in the script with your URL:

   sudo nano /usr/local/bin/docker-monitor.sh
   # Find and replace this line:
   SLACK_WEBHOOK_URL="https://hooks.slack.com/services/YOUR/WEBHOOK/URL"

3. Start it up! 🚀

Time to get this baby running:

# Reload systemd to pick up the new service
sudo systemctl daemon-reload

# Enable it to start on boot (because who wants to do this manually?)
sudo systemctl enable docker-monitor

# Start it right now
sudo systemctl start docker-monitor

4. Check if it's working

Let's make sure everything's running smoothly:

# Check the service status
sudo systemctl status docker-monitor

# Take a peek at the logs
sudo journalctl -u docker-monitor -f
# or
sudo tail -f /var/log/docker-monitor.log

Common Commands 🛠️

Here are some handy commands you might need:

# Stop the monitor
sudo systemctl stop docker-monitor

# Start it up again
sudo systemctl start docker-monitor

# Restart it (turn it off and on again, the universal fix!)
sudo systemctl restart docker-monitor

# Don't want it to start on boot?
sudo systemctl disable docker-monitor

# Check its current status
sudo systemctl status docker-monitor

Troubleshooting 🔍

Nothing's happening when containers crash

1. Check if the service is running:

   sudo systemctl status docker-monitor

2. Make sure your Slack webhook is correct:

   # Test the webhook directly
   curl -X POST -H 'Content-type: application/json' \
       --data '{"text":"Test message"}' \
       YOUR_WEBHOOK_URL

3. Check the logs:

   sudo journalctl -u docker-monitor -f

Getting duplicate notifications

This shouldn't happen with the latest version, but if it does:

1. Stop the service
2. Clear the logs
3. Restart the service

sudo systemctl stop docker-monitor
sudo truncate -s 0 /var/log/docker-monitor.log
sudo systemctl start docker-monitor

Files Location Map 🗺️

Just so you know where everything lives:

• Script: /usr/local/bin/docker-monitor.sh
• Service file: /etc/systemd/system/docker-monitor.service
• Log file: /var/log/docker-monitor.log