Monitor Docker Logs in Real-Time with a Simple Bash Script

Step 1: Ensure Docker is Installed and Running Make sure you have Docker installed and running on your system. To check if Docker is installed, run: docker --version To verify if Docker is running, use: docker ps If Docker is not running, start it using: sudo systemctl start docker Step 2: Create the Log Monitoring Script Open a terminal and create a new script file: vim monitor_docker_logs.sh Copy and paste the following script into the file: #!/bin/bash # Define log file LOG_FILE="consolidated_logs.log" ERROR_LOG_FILE="error_logs.log" # Get list of all running containers CONTAINERS=$(docker ps --format "{{.Names}}") # Check if containers are running if [ -z "$CONTAINERS" ]; then echo "No running containers found. Exiting..." exit 1 fi # Clear previous log files echo "" > $LOG_FILE echo "" > $ERROR_LOG_FILE # Collect logs from all running containers echo "Collecting logs..." for CONTAINER in $CONTAINERS; do echo "--- Logs from $CONTAINER ---" >> $LOG_FILE docker logs --tail 100 $CONTAINER >> $LOG_FILE 2>&1 echo "\n" >> $LOG_FILE done echo "Logs consolidated in $LOG_FILE" # Monitor logs for errors echo "Scanning for errors..." grep -i "error" $LOG_FILE > $ERROR_LOG_FILE if [ -s $ERROR_LOG_FILE ]; then echo "Errors found! Check $ERROR_LOG_FILE for details." else echo "No errors found." fi # Real-time monitoring (optional) echo "Monitoring logs in real-time..." tail -f $LOG_FILE Step 3: Grant Execute Permissions Make the script executable by running: chmod +x monitor_docker_logs.sh Step 4: Run the Script Start the script by executing: ./monitor_docker_logs.sh Step 5: Check the Log Files Once the script runs, it will generate two log files: consolidated_logs.log → Contains all logs from running containers. error_logs.log → Extracts error messages from the logs. To view the logs, use: cat consolidated_logs.log To check for errors, use: cat error_logs.log Step 6: Keep Monitoring Logs in Real-Time (Optional) To continuously monitor logs, use: tail -f consolidated_logs.log Step 7: Stop the Script If you want to stop real-time monitoring, press CTRL + C.

Mar 12, 2025 - 19:35

Monitor Docker Logs in Real-Time with a Simple Bash Script

Step 1: Ensure Docker is Installed and Running

Make sure you have Docker installed and running on your system.

To check if Docker is installed, run:

docker --version

To verify if Docker is running, use:

docker ps

If Docker is not running, start it using:

sudo systemctl start docker

Step 2: Create the Log Monitoring Script

Open a terminal and create a new script file:

vim monitor_docker_logs.sh

Copy and paste the following script into the file:

#!/bin/bash

# Define log file
LOG_FILE="consolidated_logs.log"
ERROR_LOG_FILE="error_logs.log"

# Get list of all running containers
CONTAINERS=$(docker ps --format "{{.Names}}")

# Check if containers are running
if [ -z "$CONTAINERS" ]; then
    echo "No running containers found. Exiting..."
    exit 1
fi

# Clear previous log files
echo "" > $LOG_FILE
echo "" > $ERROR_LOG_FILE

# Collect logs from all running containers
echo "Collecting logs..."
for CONTAINER in $CONTAINERS; do
    echo "--- Logs from $CONTAINER ---" >> $LOG_FILE
    docker logs --tail 100 $CONTAINER >> $LOG_FILE 2>&1
    echo "\n" >> $LOG_FILE
done

echo "Logs consolidated in $LOG_FILE"

# Monitor logs for errors
echo "Scanning for errors..."
grep -i "error" $LOG_FILE > $ERROR_LOG_FILE

if [ -s $ERROR_LOG_FILE ]; then
    echo "Errors found! Check $ERROR_LOG_FILE for details."
else
    echo "No errors found."
fi

# Real-time monitoring (optional)
echo "Monitoring logs in real-time..."
tail -f $LOG_FILE