How to Get Docker Logs?

Docker logs help in monitoring and troubleshooting applications running in Docker containers. By reviewing these logs, developers can easily identify issues, understand how applications behave, and ensure they are operating correctly. This guide will help you to know how to effectively access and analyze Docker logs.

Getting Docker Logs

Step 1: Identify the Container

Docker ps command list every container that is currently operating on the Docker system:

docker ps

With the help of this command, we can able to see a list of running containers with their IDs, names, and other details.

Step 2: Retrieve Logs from a Specific Container

After identifying the container, we will use the docker logs command to extract the logs. For that, we will utilize the container ID or name.

docker logs [OPTIONS] CONTAINER

• CONTAINER: The container ID or name.
• [OPTIONS]: Various options to filter or format the logs.

To get logs from a container, run:

docker logs <container-id-or-name>

Replace <container-id-or-name> with the actual ID or name of your container.

Step 3: Use Options to Filter or Format Logs

Docker provides several options based on the demands of the user or programmers to let them get certain logs.

3.1 Tail Logs

With the help of this command we can able to see last few lines of logs:

docker logs --tail <number-of-lines> <container-id-or-name>

Replace <number-of-lines> with the number of log lines you want to see.

3.2 Follow Logs

To continuously stream logs (similar to tail -f in Linux):

docker logs -f <container-id-or-name>

This command will keep the log output open and display new log entries in real-time.

3.3 Timestamp Logs

Using this command will add a timestamp to every log item:

docker logs -t <container-id-or-name>

3.4 Retrieve Logs since a Specific Time

With the help of this command we can get logs since a specific time:

docker logs --since <timestamp> <container-id-or-name>

Replace <timestamp> with a time value (e.g., 2024-06-06T00:00:00).

Example of Docker Logs

Let’s see the all process with the help of an example:

Step 1: Pull the nginx Image

With the help of docker pull nginx command we will pull the nginx Image.

Step 2: Run the nginx Image

We will run the nginx Image by using the following command:

Step 3: Retrieve Logs from the Hello-World Container

With the help of this command we can able to get the logs assosicated with the container name:

3.1 Basic Logs

3.2 Tail Logs

3.3 Follow Logs

3.4 Timestamp Logs

Conclusion

Docker logs play an vital role in monitoring and debugging applications running in containers. The 'docker logs' command help developers to take a look at utility behavior, identify and solve problems, and make sure everything runs easily. Features like actual-time streaming, time-based filtering, and timestamps make it simpler to manipulate and analyze logs. Using these gear efficaciously helps hold higher control and reliability for containerized applications.