Docker is an open-source platform that allows you to create, deploy, and run applications in containers. Containers are lightweight, portable, and self-sufficient environments that can run on any machine that supports Docker.
Docker utilizes the host operating system’s kernel, but unlike virtual machines, it does not require the overhead of a guest operating system. Instead, it uses a container runtime and image format to package and distribute applications. This allows for faster and more efficient deployment and scaling of applications, as well as easier management of their dependencies and configurations.
Docker allows developers to package an application with all of its dependencies into a single container, which can then be run on any machine that has Docker installed. This eliminates the "works on my machine" problem, as the containerized application will always run the same, regardless of the environment it is running in.
Docker uses a client-server architecture, where the Docker client communicates with the Docker daemon, which is responsible for building, running, and managing Docker containers. The Docker daemon can run on the same machine as the client or on a remote machine.
Docker also provides a centralized hub called Docker Hub, where developers can store and share their container images, making it easy to find, download and use them.
In summary, Docker provides a way to package, distribute and run applications in a consistent and efficient manner, making the whole process more portable, manageable and scalable.
Install and configure in Centos 7
Docker is a popular containerization platform that can be installed on Centos 7, a Linux distribution. To install Docker on Centos 7, you can follow these steps:
- Update the package list:
sudo yum update
- Add the Docker repository to your system:
sudo yum install -y yum-utils device-mapper-persistent-data lvm2
sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
- Install Docker:
sudo yum install -y docker-ce
- Start the Docker service:
sudo systemctl start docker
- Verify that Docker is running by checking the status of the service:
sudo systemctl status docker
- To make Docker start automatically on system boot, use the following command:
sudo systemctl enable docker
- To check the version of Docker that is running:
docker --version
- To run the hello-world container:
docker run hello-world
Please note that these are general steps and the specific commands may vary depending on your version of Centos and Docker. Also, it's recommended to read the Docker official documentation for more information.