What is Docker?
Definition 1:
Docker is a set of Platforms as a service (PaaS)
products that use Operating system-level
virtualization to deliver software in packages called
containers.
https://www.geeksforgeeks.org/introduction-to-docker/
What is Docker?
Definition 2:
Docker is a software platform that allows you to build,
test, and deploy applications quickly. Docker packages
software into standardized units called containers.
https://aws.amazon.com/docker/
What is Docker?
Definition 3:
Docker is an open-source platform that enables
developers to build, deploy, run, update and
manage containers.
https://www.ibm.com/think/topics/docker
What is Docker?
Definition 4:
Docker is an open platform for developing, shipping, and
running applications. Docker enables you to separate your
applications from your infrastructure so you can deliver
software quickly. With Docker, you can manage your
infrastructure in the same ways you manage your applications..
https://docs.docker.com/get-started/docker-overview/
What is Container?
Definition 1:
A container is a standard unit of software that packages up
code and all its dependencies so the application runs
quickly and reliably from one computing environment to
another.
https://www.docker.com/resources/what-container/
What is Container?
Definition 2:
Containers are packages of software that contain all of the
necessary elements to run in any environment. In this way,
containers virtualize the operating system and run anywhere,
from a private data center to the public cloud or even on a
developer’s personal laptop.
https://cloud.google.com/learn/what-are-containers
What is Container?
Definition 3:
Containers are executable units of software that package
application code along with its libraries and dependencies.
They allow code to run in any computing environment,
whether it be desktop, traditional IT or cloud infrastructure.
https://www.ibm.com/topics/containers
What is Container?
Definition 4:
Containers are technologies that allow the packaging and
isolation of applications with their entire runtime
environment—all of the files necessary to run. This makes it
easy to move the contained application between environments.
https://www.redhat.com/en/topics/containers
https://www.docker.com/resources/what-container/
https://www.javatpoint.com/what-are-containers
What is Docker Image?
Docker Image is an executable package of software that includes
everything needed to run an application.
This image informs how a container should instantiate, determining
which software components will run and how.
https://www.geeksforgeeks.org/what-is-docker-image/
What is Docker Image?
Docker images are read-only templates that contain
instructions for creating a container. A Docker image is a
snapshot or blueprint of the libraries and dependencies
required inside a container for an application to run.
https://aws.amazon.com/compare/the-difference-between-docker-
images-and-containers/
What is Docker Image?
A Docker image is a file used to execute code in a
Docker container. Docker images act as a set of instructions to
build a Docker container, such as a template.
Docker is an opensource project that's used to create, run and
deploy applications in containers. A Docker image contains
application code, libraries, tools, dependencies and other files
needed to make an application run.
https://www.techtarget.com/searchitoperations/definition/Docker-image
Key Concepts:
Containers: Docker Engine:
•A container is like a box that holds your app and •This is the software that actually
everything it needs to run. runs and manages containers.
•This box is isolated from other applications running on • It’s like the engine in a car that
the same machine, meaning they don’t interfere with makes everything run smoothly.
each other.
Docker Hub:
Images: •This is like an online store
•An image is a template or blueprint for creating a where you can find ready-made
container. It contains the application code, libraries, and containers or share your own.
other things that the application needs to run. • You can think of it like an app
•You can think of an image like a recipe, and a container store for containers—developers
like a dish that’s made by following that recipe. upload their images, and others
can download and use them.
What is Docker Engine:
Docker Engine is the actual technology behind building,
shipping, and running container applications.
Docker Engine is an open-source technology that includes a
server running a background process.
What is Docker Engine:
The Docker Engine enables containerized applications to run
anywhere consistently on any infrastructure, solving
dependency issues for developers and operations teams.
The Docker Engine encompasses a full set of features and tools
to help users be as efficient as possible when working with
containers.
https://docker.awsworkshop.io/0_introduction/10_docker_engine.html
https://alicanakkus.github.io/blog/docker/docker-containers
https://alicanakkus.github.io/blog/docker/docker-containers
What is Docker Hub?
Docker Hub simplifies development with a powerful container
registry for storing, managing, and sharing Docker images.
Docker Hub simplifies development with the world's largest
container registry for storing, managing, and sharing Docker
images.
https://docs.docker.com/docker-hub/
What is Docker Hub?
Docker Hub is a repository service and it is a cloud-based
service where people push their Docker Container Images and
also pull the Docker Container Images from the Docker
Hub anytime or anywhere via the internet.
https://www.geeksforgeeks.org/what-is-docker-hub/
What is Docker Hub?
• It is an open-source tool and freely available for all operating
systems. It is like storage where we store the images and pull
the images when it is required.
• It provides features such as you can push your images as
private or public.
https://www.geeksforgeeks.org/what-is-docker-hub/
https://www.geeksforgeeks.org/what-is-docker-hub/
Purpose of Docker:
Docker is to make it easier to develop, test, and deploy applications in a way that is consistent, fast, and
portable across different environments.
Makes Apps Work Everywhere: Uses Fewer Resources:
•Docker helps your app run the same way •Docker is light and fast. It doesn't use as much memory
everywhere. Whether it's on your laptop, a friend's or processing power as traditional virtual machines, so
computer, or a cloud server, Docker makes sure the your computer or server can run more apps at once without
app behaves the same, no surprises! slowing down.
Easier to Move Apps Around: Makes Development and Deployment Easy:
•With Docker, you can move your app from one •Developers can build and test apps in Docker and be sure
place to another easily. If you build an app on your they’ll work exactly the same way when they're ready to
computer, you can quickly move it to a server or the launch. It’s also easier to deploy apps to a live server or
cloud without worrying about things not working. cloud because Docker ensures everything is set up
correctly.
Keeps Things Separate:
•Docker keeps apps separate from each other. This Works Well for Big Projects:
means if you have one app that needs special tools, •Docker is great when you have a big app made of smaller
and another one needs different tools, Docker makes parts (called microservices). It makes it easy to manage and
sure they don't mess with each other. scale those parts, so your app can grow smoothly.
Key Features of Docker:
• Open-source platform
• An Easy, lightweight, and consistent way of delivery of applications
• Fast and efficient development life cycle.
• Segregation of duties
• Service-oriented architecture
• Security
• Scalability
• Reduction in size
• Image management
• Networking
• Volume management
Advantages and Disadvantages of Docker:
S.NO Advantages Disadvantages
Increased complexity cost and
1 Flexible & powerful
high-Security restrictions.
Socket-based communications
2 Very sufficient allow only to send packets of
raw data between applications.
Communication can be
Updated Information can be
established with the machine
3 used to send only between
requested not with another
devices
machine.
Low network traffic if efficient Both ends should have the
4
use ability to intercept the data.
Advantages of Docker:
Portability: Containers run consistently across different environments (development, staging,
production).
Lightweight: Containers are faster and consume fewer resources than virtual machines.
Isolation: Containers are isolated, preventing conflicts between applications and dependencies.
Faster Development and Deployment: Quick container creation and deployment accelerate
development cycles.
Scalability: Easy to scale applications using orchestration tools like Kubernetes.
Microservices Support: Ideal for running microservices with separate containers for each service.
CI/CD Integration: Seamless integration with Continuous Integration and Deployment pipelines.
Improved Security: Strong isolation and the ability to restrict container privileges enhance
security.
Cost-Efficient: Better resource utilization reduces infrastructure costs.
Version Control: Docker images can be versioned, allowing easy rollbacks and updates.
Disadvantages of Docker:
Security Concerns: Containers share the host OS kernel, which can lead to potential
security vulnerabilities if not properly managed.
Complexity in Management: Managing large-scale containerized environments can be
complex, especially without tools like Kubernetes.
Limited GUI Support: Docker primarily works through the command line, which may be
challenging for those preferring graphical interfaces.
Performance Overhead: Although lightweight, Docker containers still introduce some
performance overhead compared to running applications natively.
Compatibility Issues: Some applications may not be well-suited for containerization,
especially those requiring direct access to hardware or low-level resources.
Persistent Storage: Handling persistent storage and managing data in containers can be
complex, as containers are designed to be ephemeral.
Learning Curve: For newcomers, understanding containerization concepts and best
practices can take time.
