Having a custom image allows applications to be scaled on-demand via orchestration tools (Kubernetes, Rancher, Kasm, etc.) because containers can be spun up in milliseconds straight from an image.<\/p>\n
MAIN STEPS<\/strong><\/p>\n Additional instructions can be added as needed:<\/p>\n Note:<\/strong> INSTALL LATEST DOCKER FROM OFFICIAL REPOSITORY<\/strong><\/p>\n EXAMPLES<\/strong><\/p>\n Create a file named BUILD<\/strong><\/p>\n RUN<\/strong><\/p>\n RUN STAGE<\/strong><\/p>\n PUBLISHING IMAGES<\/strong><\/p>\n Images (also referred to as Artifacts) can be published to a remote registry for public or private use, with access control support.<\/p>\n The two most popular container registries are Docker Hub<\/strong> and GitHub Container Registry<\/strong>. See the examples below for pushing images to both using GitHub Actions<\/strong>.<\/p>\n\n
Dockerfile<\/code>.<\/li>\n\n
FROM<\/code> – specifies the base image to build from.<\/li>\nRUN<\/code> – executes commands during the image build process.<\/li>\nCOPY<\/code> \/ ADD<\/code> – copies files or directories into the image.<\/li>\nCMD<\/code> – specifies the command to run when a container is started from the image.<\/li>\n<\/ul>\n<\/li>\ndocker build<\/code> with the -t<\/code> flag to assign it a name.<\/li>\n<\/ul>\n\n
ENV<\/code> – sets environment variables in the image.<\/li>\nEXPOSE<\/code> – declares which ports the container will listen on at runtime.<\/li>\nUSER<\/code> – sets the UID and\/or GID that CMD<\/code> will run as.<\/li>\nWORKDIR<\/code> – sets the working directory for subsequent instructions like RUN<\/code> and CMD<\/code>.<\/li>\nVOLUME<\/code> – creates a persistent volume that survives container restarts.<\/li>\nCOPY<\/code> and ADD<\/code> are not the same. COPY<\/code> only copies local files and directories from the build context into the image. ADD<\/code> also supports extracting compressed archives (such as tar or zip files) and copying files from a remote URL.<\/p>\n
\nsudo apt update\r\nsudo apt install ca-certificates curl\r\nsudo install -m 0755 -d \/etc\/apt\/keyrings\r\nsudo curl -fsSL https:\/\/download.docker.com\/linux\/ubuntu\/gpg -o \/etc\/apt\/keyrings\/docker.asc\r\nsudo chmod a+r \/etc\/apt\/keyrings\/docker.asc\r\nsudo nano \/etc\/apt\/sources.list.d\/docker.sources<\/pre>\n
Types: deb\r\nURIs: https:\/\/download.docker.com\/linux\/ubuntu\r\nSuites: $(. \/etc\/os-release && echo \"${UBUNTU_CODENAME:-$VERSION_CODENAME}\")\r\nComponents: stable\r\nArchitectures: amd64\r\nSigned-By: \/etc\/apt\/keyrings\/docker.asc<\/pre>\nsudo apt update\r\nsudo apt install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin -y\r\nsudo systemctl status docker<\/pre>\n
\nDockerfile<\/code> and add the build instructions. See examples below:<\/p>\n\n
FROM alpine:latest\r\nCOPY .\/hello.sh \/usr\/local\/bin\/hello\r\nRUN chmod +x \/usr\/local\/bin\/hello\r\nCMD [\"\/usr\/local\/bin\/hello\"]<\/pre>\n
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FROM python:3.9-alpine\r\nENV PYTHONUNBUFFERED 1\r\nCOPY . \/app\r\nWORKDIR \/app\r\nRUN pip install --upgrade pip\r\nRUN pip install -r requirements.txt\r\nEXPOSE 80:5000\/tcp\r\nCMD [\"flask\", \"run\", \"--host=0.0.0.0\"]<\/pre>\n
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FROM louislam\/uptime-kuma\r\nRUN apt update \r\nRUN apt install nano htop curl -y\r\nEXPOSE 3001\/tcp\r\n<\/pre>\n
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FROM postgres:17.7\r\nENV POSTGRES_DB dbHost\r\nENV POSTGRES_USER dbUser\r\nENV POSTGRES_PASSWORD dbPassword\r\nCOPY init.sql \/docker-entrypoint-initdb.d\/\r\nEXPOSE 5432<\/pre>\n
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FROM registry.access.redhat.com\/ubi10\/ubi:latest\r\nRUN dnf install -y httpd && \\\r\n dnf clean all && \\\r\n rm -rf \/var\/cache\/dnf\r\nENV CACHE=\/tmp\/cache\r\nRUN mkdir -p \/devenv\r\nADD . \/devenv\r\nWORKDIR \/devenv\r\nRUN \/devenv\/script.sh\r\nEXPOSE 8080:80\r\nCMD [\"\/dev\/entry-point.sh\"]<\/pre>\n
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FROM registry.access.redhat.com\/ubi10\/ubi-init\r\nRUN dnf install -y --nodocs --setopt install_weak_deps=false http mariadb && \\\r\n dnf clean all\r\nEXPOSE 80 3306\r\nRUN systemctl enable httpd mariadb<\/pre>\n
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FROM fedora:latest\r\nENV LIBGUESTFS_BACKEND=direct\r\nRUN dnf -y install virt-v2v dnf-plugins-core wget\r\nRUN wget https:\/\/fedorapeople.org\/groups\/virt\/virtio-win\/virtio-win.repo -O \/etc\/yum.repos.d\/virtio-win.repo && \\\r\n dnf -y install virtio-win\r\nRUN dnf clean all && \\\r\n rm -rf \/var\/cache\/dnf\r\n<\/pre>\n
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FROM debian:12\r\nRUN apt update\r\nRUN apt install nano htop curl wget -y\r\nRUN wget -O \/tmp\/cloudflared.deb -q https:\/\/github.com\/cloudflare\/cloudflared\/releases\/latest\/download\/cloudflared-linux-amd64.deb\r\nRUN dpkg -i \/tmp\/cloudflared.deb && rm \/tmp\/cloudflared.deb\r\nCMD [\"sh\", \"-c\", \"\/usr\/bin\/cloudflared --no-autoupdate tunnel run --token
sudo docker build -t customImageName:v1.0<\/strong> .<\/pre>\n
sudo docker run --name containerName<\/strong> customImageName:v1.0<\/pre>\n
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FROM php:8-apache-trixie AS base<\/strong>\r\nRUN a2enmod rewrite\r\nWORKDIR \/var\/www\/\r\nEXPOSE 80\/tcp\r\nCMD [\"apache2-foreground\"]\r\n\r\nFROM base AS dev<\/strong>\r\nRUN apt update && apt install -y curl nano htop\r\nFROM base AS final<\/pre>\n
sudo docker run --target base<\/strong> customImageName<\/pre>\n
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name: Build and Push Multi-Arch Docker Image\r\n\r\non:\r\n push:\r\n branches:\r\n - main\r\n\r\njobs:\r\n build-and-push:\r\n runs-on: ubuntu-latest\r\n\r\n steps:\r\n - name: Checkout code\r\n uses: actions\/checkout@v3\r\n\r\n - name: Set up Docker Buildx\r\n uses: docker\/setup-buildx-action@v2\r\n\r\n - name: Log in to Docker Hub\r\n uses: docker\/login-action@v2\r\n with:\r\n username: ${{ secrets.DOCKER_USERNAME }}\r\n password: ${{ secrets.DOCKER_PASSWORD }}\r\n\r\n - name: Build and push multi-arch image\r\n uses: docker\/build-push-action@v5\r\n with:\r\n context: .\r\n platforms: linux\/amd64,linux\/arm64\r\n push: true\r\n tags: ${{ secrets.DOCKER_USERNAME }}\/${{ github.event.repository.name }}:latest<\/pre>\n