Building Docker Images - A Step-by-Step Guide with Example
Docker is an open-source platform that enables the creation, deployment, and management of applications within lightweight, isolated containers. It provides a consistent and efficient way to package software and its dependencies, ensuring that applications run reliably across different computing environments.
What is Docker?
Docker is an open-source platform that enables the creation, deployment, and management of applications within lightweight, isolated containers. It provides a consistent and efficient way to package software and its dependencies, ensuring that applications run reliably across different computing environments.
Docker containers share the host OS kernel, making them more lightweight and efficient than traditional virtual machines.
Docker Architecture
Key Benefits
Portability
Run consistently across dev, test, and production. Eliminates "it works on my machine" problems.
Scalability
Deploy multiple container instances quickly. Scale up or down based on demand.
Resource Efficiency
Lightweight containers share host resources. Higher density than VMs.
Isolation
Applications run independently. Enhanced security and no dependency conflicts.
Version Control
Version-controlled images enable easy rollbacks and change tracking.
Rapid Deployment
Standardized environment reduces deployment time from hours to seconds.
Docker Components
Text file containing instructions to build a Docker image. Each instruction creates a new layer.
Read-only template containing application code, runtime, libraries, and dependencies. Used to create containers.
Runnable instance of an image. Has a writable layer on top of the image for runtime changes.
Storage and distribution system for Docker images. Docker Hub is the default public registry.
Background service (dockerd) that manages Docker objects. Listens for API requests from CLI.
Installation & Configuration of Docker
To install Docker Engine on a new host machine, it is important to first set up the Docker repository. Once the repository is configured, you can proceed with installing and updating Docker using the repository.
Set up the repository
It provide instructions to set up the necessary repository and prerequisites for installing the Docker engine based on the operating system (OS) in use.
sudo apt-get update
sudo apt-get install \
ca-certificates \
curl \
gnupg \
lsb-release
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/debian/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
echo \
"deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/debian \
$(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo yum install -y yum-utils
sudo yum-config-manager \
--add-repo \
https://download.docker.com/linux/centos/docker-ce.repo
$ sudo apt-get update
$ sudo apt-get install docker-ce docker-ce-cli containerd.io docker-compose-plugin
yum install docker-ce docker-ce-cli containerd.io docker-compose-plugin
Last updated 2 weeks ago
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