How to Build Docker Image from a Dockerfile

Posted on

Introduction

This is an article showing how to build a docker image using a Dockerfile file. But in this article, it will just show a minimum requirement for building the docker image. By executing a certain command using a Dockerfile, it will generate docker image. Building the image is possible in any kind of operating system as long as the requirement is available.

Build Docker Image from a Dockerfile

So, how is the process for building a docker image using docker command with the definition of a Dockerfile file ?. Basically, there are several requirements which is very important to do that. The following are those requirements to be able to do that :

  1. Check whether docker tool is avaiable or not. It is very easy to do it. Just execute ‘docker’ in the command line. If there is no docker tool available in the operating system, just install it first. There are so many articles in this site discussing about how to install docker. The first one is ‘How to Install Docker CE in Linux CentOS 7’ in this link. Furthermore, there is an article with the title of ‘How to Install Docker in Linux CentOS 8’ in this link. Another one is an article with the title of ‘How to Install Docker in Linux Ubuntu 18.04 Bionic Beaver’ in this link. The last one is ‘Install Docker in CentOS 7 via command line’ in this link. Otherwise, just search by googling it.

  2. Test it again by executing the command ‘docker’ as follows :

    Microsoft Windows [Version 10.0.18363.628]
    (c) 2019 Microsoft Corporation. All rights reserved.
    
    C:\Users\Administrator>docker
    
    Usage: docker [OPTIONS] COMMAND
    
    A self-sufficient runtime for containers
    
    Options:
    --config string Location of client config files (default
    "C:\\Users\\Administrator\\.docker")
    -c, --context string Name of the context to use to connect to the
    daemon (overrides DOCKER_HOST env var and
    default context set with "docker context use")
    -D, --debug Enable debug mode
    -H, --host list Daemon socket(s) to connect to
    -l, --log-level string Set the logging level
    ("debug"|"info"|"warn"|"error"|"fatal")
    (default "info")
    --tls Use TLS; implied by --tlsverify
    --tlscacert string Trust certs signed only by this CA (default
    "C:\\Users\\Administrator\\.docker\\ca.pem")
    --tlscert string Path to TLS certificate file (default
    "C:\\Users\\Administrator\\.docker\\cert.pem")
    --tlskey string Path to TLS key file (default
    "C:\\Users\\Administrator\\.docker\\key.pem")
    --tlsverify Use TLS and verify the remote
    -v, --version Print version information and quit
    
    Management Commands:
    builder Manage builds
    buildx* Build with BuildKit (Docker Inc., v0.6.3)
    compose* Docker Compose (Docker Inc., v2.1.1)
    config Manage Docker configs
    container Manage containers
    context Manage contexts
    image Manage images
    manifest Manage Docker image manifests and manifest lists
    network Manage networks
    node Manage Swarm nodes
    plugin Manage plugins
    scan* Docker Scan (Docker Inc., 0.9.0)
    secret Manage Docker secrets
    service Manage services
    stack Manage Docker stacks
    swarm Manage Swarm
    system Manage Docker
    trust Manage trust on Docker images
    volume Manage volumes
    
    Commands:
    attach Attach local standard input, output, and error streams to a running container
    build Build an image from a Dockerfile
    commit Create a new image from a container's changes
    cp Copy files/folders between a container and the local filesystem
    create Create a new container
    diff Inspect changes to files or directories on a container's filesystem
    events Get real time events from the server
    exec Run a command in a running container
    export Export a container's filesystem as a tar archive
    history Show the history of an image
    images List images
    import Import the contents from a tarball to create a filesystem image
    info Display system-wide information
    inspect Return low-level information on Docker objects
    kill Kill one or more running containers
    load Load an image from a tar archive or STDIN
    login Log in to a Docker registry
    logout Log out from a Docker registry
    logs Fetch the logs of a container
    pause Pause all processes within one or more containers
    port List port mappings or a specific mapping for the container
    ps List containers
    pull Pull an image or a repository from a registry
    push Push an image or a repository to a registry
    rename Rename a container
    restart Restart one or more containers
    rm Remove one or more containers
    rmi Remove one or more images
    run Run a command in a new container
    save Save one or more images to a tar archive (streamed to STDOUT by default)
    search Search the Docker Hub for images
    start Start one or more stopped containers
    stats Display a live stream of container(s) resource usage statistics
    stop Stop one or more running containers
    tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
    top Display the running processes of a container
    unpause Unpause all processes within one or more containers
    update Update configuration of one or more containers
    version Show the Docker version information
    wait Block until one or more containers stop, then print their exit codes
    
    Run 'docker COMMAND --help' for more information on a command.
    
    To get more help with docker, check out our guides at https://docs.docker.com/go/guides/
    
    C:\Users\Administrator>
    
  3. Next, since docker is available just create the file with the name of ‘Dockerfile’ with the following content :

    # pull image
    FROM centos
    
  4. Finally, execute the following command to build the image :

    C:\Users\Administrator>docker build .
    [+] Building 0.6s (5/5) FINISHED
    => [internal] load build definition from Dockerfile 0.7s
    => => transferring dockerfile: 32B 0.1s
    => [internal] load .dockerignore 0.6s
    => => transferring context: 2B 0.1s
    => [internal] load metadata for hub.docker.local:5000/centos:latest 0.0s
    => CACHED [1/1] FROM hub.docker.local:5000/centos 0.0s
    => exporting to image 0.0s
    => => exporting layers 0.0s
    => => writing image sha256:22773018c04267669821153cd42ef21101902b10a8a16f340fbef85a77821d03 0.0s
    
    Use 'docker scan' to run Snyk tests against images to find vulnerabilities and learn how to fix them
    
    C:\Users\Administrator>
  5. Finally, the following is the command to check the image built from the previous process :
    C:\Users\Administrator>docker image list --all
    REPOSITORY                   TAG    IMAGE ID     CREATED      SIZE
    registry                     latest b8604a3fe854 3 weeks ago  26.2MB
    bash                         latest bacfc038bc2c 3 weeks ago  12.9MB
    <none>                       <none> 22773018c042 2 months ago 231MB
    centos                       latest 5d0da3dc9764 2 months ago 231MB
    hub.docker.local:5000/centos latest 5d0da3dc9764 2 months ago 231MB
    
    C:\Users\Administrator>

    In the above output, the one without any name in the repository and tag column is the new created image.

One thought on “How to Build Docker Image from a Dockerfile

Leave a Reply