Skip to main content
Welcome to this comprehensive guide on managing application logs in Kubernetes. In this article, we explore various logging mechanisms, starting with Docker and moving on to Kubernetes, to help you monitor and troubleshoot your applications effectively.

​
Logging in Docker

Docker containers typically log events to the standard output. Consider the “event simulator” container, which generates random events simulating a web server. When you run this container, it writes log entries such as:
If you run the container in detached mode using the -d flag, the logs will not appear on your terminal immediately. Instead, you can stream them later with:

​
Logging in Kubernetes

Deploying the same Docker image within a Kubernetes pod leverages Kubernetes’ logging capabilities. To get started, create a pod using the following YAML definition:
Create the pod with this command:
Once the pod is running, view the live logs using:
This command outputs logs similar to the Docker example:
For more effective troubleshooting, use log filtering and analysis tools in combination with Kubernetes logs.

​
Logging with Multiple Containers in a Pod

Kubernetes supports pods with multiple containers. If you update your pod definition to include an additional container named image-processor, the configuration will look like this:
Create the pod using:
Attempting to view logs without specifying the container when multiple containers are present will result in an error. Instead, specify the container name to view its logs:
This command displays log output for the event-simulator container:
When working with pods that contain multiple containers, always specify the container name in the kubectl logs command to avoid errors.

​
Additional Resources

For further information on logging and monitoring in Kubernetes, refer to the following resources: By mastering these logging techniques, you ensure efficient monitoring and troubleshooting of your applications in both Docker and Kubernetes environments. Happy logging! Thank you.

Watch Video

Practice Lab