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rakesh kumar
rakesh kumar

Posted on • Updated on

List out the checklist of docker image command

What-are-the-differences-between-a-vm-image-and-a-docker-image
A Docker image is a read-only template that contains a set of instructions for building Docker containers. It’s an executable package (a collection of files or layers) that contains everything you’ll need to set up a fully functional container environment, including application code, dependencies, software packages, and more. A Docker image can be created in one of two ways:

Interactive

Dockerfile
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1. Create a Dockerfile:
Create a Dockerfile in your project directory. This file defines the steps to build the image.
2. Build the Docker Image:
Use the docker build command to build an image from the Dockerfile.

docker build -t myimage:1.0 .
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-t tags the image with a name and version.
3. List Docker Images:
Verify that the image has been created.

docker images
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4. Inspect the Image:
Inspect detailed information about the created image.

docker image inspect myimage:1.0
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5. Remove an Image:
If needed, remove the image.

docker rmi myimage:1.0
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6. Build with Build Arguments:
Use build arguments in the Dockerfile and pass values during the build.

docker build --build-arg MY_VARIABLE=value -t myimage:1.0 .
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7. Build with Cache:
Leverage Docker's layer caching to speed up builds by reusing layers.

docker build -t myimage:1.0 .
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8. Multi-Stage Builds:
Use multi-stage builds to create smaller final images.

FROM node:14 AS builder
WORKDIR /app
COPY . .
RUN npm install
RUN npm run build

FROM nginx:alpine
COPY --from=builder /app/dist /usr/share/nginx/html
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9. Dockerignore:
Create a .dockerignore file to exclude unnecessary files from the build context.

node_modules
.git
.dockerignore
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10. Label the Image:

  • Add metadata labels to the image. 
 LABEL version="1.0" maintainer="yourname@example.com"
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11. Specify the Working Directory:

  • Set the working directory in the Dockerfile. 
 WORKDIR /app
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12. Cleanup Unnecessary Layers:

  • Combine commands and cleanup to minimize the number of layers. 
 RUN apt-get update && \
     apt-get install -y some-package && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
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13. Use Official Base Images:

  • Choose official base images from trusted sources. 
 FROM node:14
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14. Expose Ports:

  • Use the EXPOSE instruction to document which ports the application needs. 
 EXPOSE 3000
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15. Health Checks:

  • Implement a health check in the Dockerfile. 
 HEALTHCHECK CMD curl --fail http://localhost:3000 || exit 1
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This checklist covers the essential steps and commands for creating Docker images. Adjustments can be made based on the specific requirements of your application and development practices.

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