Mastering Docker: How to Launch Containers with CPU and Memory Limits

In this tutorial, we’ll walk you through the process of launching Docker containers with specific CPU and memory restrictions. So, let’s dive right in and learn how to harness the full power of Docker’s resource management capabilities.

To set CPU and memory limits for your containers, we’ll use the docker container run command. Let’s first start by launching a container without any resource restrictions.

docker container run -dit --name ubuntu_limits ubuntu

In this command:

  • -dit: These flags run the container in detached mode and allocate a pseudo-TTY.
  • --name ubuntu_limits: We’re giving our container a name, ‘ubuntu_limits.’
  • ubuntu: This is the Docker image we’re using.

This command will create a container named ‘ubuntu_limits’ running an Ubuntu image without any resource limits. To specify CPU and memory restrictions, we can simply add the following parameters:

  • --cpus=".25": Here, we’re allocating a quarter of a CPU core to the container. If you want to use more or less CPU, you can adjust this number accordingly.
  • --memory 100m: This sets a memory limit of 100 MB for the container. You can change this value to allocate more or less memory.

Now, let’s run the container with these CPU and memory restrictions:

docker container run -dit --name ubuntu_limits --cpus=".25" --memory 100m ubuntu

With these restrictions in place, your Docker container will have access to only a quarter of a CPU core and will be limited to using 100 MB of memory.

To verify that these limits are in effect, you can inspect the running container using the following command, where 57e1 should be replaced with your actual container ID:

docker container inspect 57e1 | grep -i 'NanoCpus\|Memory'
  • NanoCpus: This line will show the CPU limit in nanocpus. The value 200000000 corresponds to 0.2 (0.2 CPU core).
  • Memory: This line will display the memory limit. If you set it to 100MB, you should see 104857600 for memory.

By using these commands, you can effortlessly launch Docker containers with specific CPU and memory restrictions. This level of control is invaluable when you need to manage resource allocation and ensure that your containers don’t consume excessive system resources.

Resource management in Docker is a crucial aspect of containerization, allowing you to optimize performance and resource usage. These simple commands give you the power to fine-tune your containers and create a more efficient and stable containerized environment.

So, next time you’re launching Docker containers, don’t forget to explore these resource management options. Your system resources will thank you!

That’s it for this short tutorial. Stay tuned for more Docker insights and practical demos. Happy containerizing!

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