Docker registry – trying to simplify concept and bit details

Hi All,
Greetings for the day 🙂 LIFE IS BEAUTIFUL 🙂
Background : Since exploring Docker / Kubernetes, recently got an assignment to create Private registry and push our docker images to our private registry
Before discussing private registry and how to create it, here I will discuss first what is Docker Registry? Types of Docker Registry ? and few more details
What is Docker Registry ?
- A Docker registry is the storage for our docker image
- As we discussed in previous articles as well – Docker Image is nothing but read-only template which contains set of instructions for creating container which runs on Docker platform
- These images within registries are available either public – can be downloaded by anyone OR private – restricted access to users
- Registry is nothing but instance of registry image and runs within Docker
- We interact with registry using Push and Pull commands
- Its the service which hosts and distributes Docker images
- We could host Docker registries either in cloud or on-premises
- The Registry is stateless
- The Registry is open-source
- We could have either Public Registry OR Private Registry
- Some example of public Docker registries are
- Googles container registry (GCR)
- It supports only private registries
- It supports automated image build via GitHub
- Amazon’s Elastic Container Registry (ECR)
- It supports only private registries
- It doesn’t support automated image building
- Azure Container Registry (ACR)
- It supports only private registries
- It does not provide automated image building
- Googles container registry (GCR)
- We can create our private registry deriving from Official registry image – registry version 2 – we will discuss this in next article
Prerequisites :
- Docker must be installed to have Docker registry
What is Docker Hub?
- Docker Hub is official cloud based repository for Docker images
- This is default registry
- This registry is ready when we install Docker
- The Registry is compatible with Docker engine version 1.6.0 or higher.
- Docker Hub registry is free to use
- We have very good articles on Docker installation
- Docker Hub supports the integration with Github – we will discuss how this happen in upcoming articles
- It hosts around 8,836,465 images and 170+ official images
Interacting with Registry : (Here using default registry – Docker Hub)
- Pushing our Docker image to registry :
- We have very good article on pushing our image to Docker Hub, please have a look once – Docker : How to push docker image to docker hub – resolving error – “denied: requested access to the resource is denied”
docker push username(dockerid)/imagename
Example:
docker push prashamsabadra/knowledgejunction:latest
here please note - "prashamsabadra" is my docker id / username
- Pulling image from registry :
docker pull <image name>
Example :
docker pull ubuntu => downloads locally image ubuntu
We have very good series of Docker / Kubernetes, trying to simplifying the concepts, please have a look once – https://knowledge-junction.in/category/containerization/
Thanks for reading 🙂 If you think its useful, kindly please like and share 🙂
HAVE A GREAT TIME AHEAD 🙂
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