How to check the memory occupied by docker container

With the development of cloud computing, more and more enterprises and individuals are beginning to adopt Docker as containerization technology. However, in the process of using Docker, we may encounter some problems, such as how to see the memory occupied by the container. This article will introduce how to check the memory occupied by Docker containers.

Docker is a lightweight virtualization technology that can help us run multiple containers on a physical machine. Each container has its own file system, network configuration, and process space, and they are isolated from each other so they can work together on the same physical machine without affecting each other. However, containers also occupy computer memory resources. If too much memory is occupied, it may cause performance problems on the system.

So, how to check the memory occupied by Docker container?

Method 1: Use the Docker stats command

The stats command that comes with Docker can monitor the memory usage of the Docker container in real time. Enter the following command in the terminal:

docker stats

This will list the statistics of all currently running containers, including the container's ID, name, CPU usage, memory usage, network I/O, etc.

However, this method is not suitable for viewing the memory usage of a specified container. If you want to view the memory usage of a single container, you can use the following command:

docker stats [容器名称 or 容器ID]

This command will output real-time statistics of the specified container, including CPU and memory usage.

Method 2: Use Docker stats and grep commands

If you want to check the memory usage of a specified container, you can also combine the grep command to filter the results. The following is a sample code that uses the grep command to filter out the memory usage of the MySQL container:

docker stats $(docker ps --format={{.Names}}) | grep mysql

This command will output the statistics of all running containers and filter out the memory usage of the MySQL container.

Method 3: Mount the /proc directory

In the Linux system, there is a meminfo file in the /proc directory, which records the memory usage in the system. If you mount the /proc directory into a container, you can view the memory usage on the host within the container. The specific operations are as follows:

Execute the following command on the host:

docker run -it --rm -v /proc:/host/proc alpine sh

This command will start a new container and mount the host's /proc directory to the container's /host/ proc directory.

Then, execute the following command in the container to check the memory usage:

cat /host/proc/meminfo

This command will output the memory usage on the host, including total memory, free memory, cache, etc. It can be analyzed and processed as needed.

Conclusion

This article introduces three methods to check the memory occupied by Docker containers, namely using the Docker stats command, Docker stats and grep commands, and mounting the /proc directory. Choose the appropriate method to check the memory usage of the container according to the specific situation, so that memory problems can be discovered and dealt with in time, and system performance can be improved.

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