2022-10-01 - 3 mins reading
Intro to Docker
You have probably heard about Docker at some time in your professional career as a developer. And as you are probably aware, it has become a crucial piece of technology for any application developer to understand.
What is Docker?
Docker is on software platform that could build and deploy virtualization to run on the same host operating system. The virtualization in Docker is performed on system-level, also called Docker containers.
The term "docker" may refer to either the tools (the commands and a daemon) or to the Dockerfile file format. Docker is developed using Go programming language.
It is also important to understand Docker “slangs 😎" such as Docker Image, Docker Registries, and Docker Container!
- Docker Image
Docker images act as a set of instructions (to execute the code) to build the container.
- Docker Registries
Docker Registries acts as a storage and distribution system for Docker images.
- Docker Container
When we create an image and begin to run it, we are doing inside of a Docker container. We could modify, create, and manage it.
Why do we need to use Docker?
Even though Containers and VM are similar in resource isolation and allocation benefits, but there is a difference between both of it which containers are more efficient since the virtualize in operating system instead of hardware.
Docker made pre-built images, meaning all the required dependencies will be included in a container.
We can see Docker images as a blueprint for docker creation. With these Docker images, developers can create
Docker containers containing the stuff they define in Dockerfile.
Many businesses have switched from virtual machines (VMs) to containers since they are not only more lighter but also very simple to maintain.
The entire ecosystem of containers can be run and maintained by one developer (or even a small team of developers) rather easily because each container can be versioned using its Dockerfile.
On the other hand, just being able to run and maintain VMs would require an infrastructure person.
Also talking about its robustness, it uses minimal memory when compared to a virtual machine (which would have a complete operating system installed and running on it). As opposed to the few minutes needed to boot up a virtual computer, this cuts down the boot-up time to only a few seconds.
Because they are stateless, containers are the ideal instrument if you want fast workloads 🚀!
Important Docker Commands
Here are some important Docker commands and its function to be noted:
| COMMAND | DEFINITION |
|---|---|
docker version | get current version of docker |
docker info | list the command information |
docker pull <image_name> | pull an image |
docker push <image_name> | push an image |
docker start <container_name> | start a running container |
docker stop <container_name> | stop a running container |
docker restart <container_name> | restart a running container |
docker rm -f <container_name> | remove forcefully a container |
docker rmi <image_name> | remove an image |
docker images | list all the images |
docker ps -a | list all the containers |
docker cleanup | remove all stopped container |
docker run <image_name> | run an image |