What is a Docker image? A Docker image is the runtime environment for your application. By ‘tagging" it, you can create and version specific images which ensures that each one of them has all the dependencies needed to run on any given platform.
The “docker build from dockerfile” is a command that allows you to create a Docker Windows image with the help of Docker.
Do you have any experience with Docker Windows Images? Do you operate in a Windows environment and want to learn more about Docker builds for container images? You’ve arrived to the correct location. Doing with the docker build and docker build “tag” commands is the greatest method to learn about new things!
In this tutorial, you’ll learn how to use the docker build command to construct your first Windows Docker image using a Dockerfile.
Let’s get going!
Docker Container Images: An Overview
For years, having numerous dedicated physical or virtual workstations imaged with the OS version of your choosing was the only method to test or develop on different operating systems (OS). Provisioning fresh workstations for each software and OS specification needed additional hardware and costs with this process.
However, the popularity of micro-service architecture has boosted the use of Docker container images in recent years. Microsoft has begun to officially offer Docker images for numerous marquee products on its Docker Hub website in response to the growing popularity of Docker. They’ve even included native support for pictures in Windows 10 and Windows Server 2016 as a product feature!
The Docker Engine is used to execute a Docker image on a container. Docker images provide several advantages, including mobility (applicable to a variety of settings and platforms), customization, and scalability. The Docker engine, unlike conventional virtual machines, operates on a layer between the host OS kernel and the separated application services being containerized, as seen below.
Docker Build and Image Understanding
You may use the docker build command to automate container image generation, adopt a container-as-code DevOps methodology, and incorporate containerization into your project’s development cycle. Dockerfiles are just text files that provide Docker’s build instructions for creating a new container image based on an existing image.
When a container image is deployed or started for the first time, the user may provide the base image and a list of commands to perform. In this post, you’ll learn how to use a Windows container to construct a Windows-based Docker image from a Dockerfile.
Using this method instead of a pre-built container image offers various advantages:
- You can recreate a container image for several Windows versions, which is useful for testing code changes across many platforms.
- You will have more control over the contents of the container. This will enable you to reduce the size of your container.
- You should verify the container for vulnerabilities and add security hardening to the base image for security reasons.
Prerequisites/Requirements
This article will lead you through the steps of creating a Docker image using a Dockerfile. If you want to follow along, make sure you have the following things in order.
- Installed Docker for Windows. In my setup, I’ll be utilizing Docker Community Edition (CE) version 2.1.0.4.
- The Docker images must be downloaded via the internet.
- Operating System: Windows 10+ (version 1709 is being used for this tutorial)
- Enabled nested virtualization
- On your local system, you have 5 GB of free storage space.
- 5.0+ PowerShell
- The Visual Studio Code IDE is used in this course. However, you are free to use any IDE you like.
When installing Docker, make sure Windows Containers Configuration is turned on.
Making Preparations
You’ll need a folder to keep track of all the Docker images and containers you’ll be creating from them. Create a new directory named C:Containers in a Powershell or cmd prompt (you’ll be using PowerShell throughout this post).
Change to that directory after the folder has been created. This sets the console’s current working directory to C:Containers, which will be the default location for all downloads.
PS51> mkdir C:Containers PS51> cd C:Containers
You’ll gain a head start in this article. The majority of the files needed to complete this project are already on hand. Perform a Git pull to transfer the files required for this post from the TechSnips Github repository to the C:Containers folder after the folder has been established. After that, double-check that the C:Containers folder looks like this.
Files with instructions
The IIS Windows Docker Image may be downloaded here.
Downloading a “template” or “base image” is the first step. Later, you’ll create your own Docker image, but initially, you’ll need an image to work with. For this lesson, you’ll need to obtain the most recent IIS and Windows Server Core Images. The official Microsoft Docker hub image page has an updated collection of images.
Examining the Existing Docker Base Images
Let’s have a look at the existing Docker base images you have on your local machine before downloading the image from the image repository. To do so, open a PowerShell console as Administrator and enter docker images in the command prompt. This command displays all photos on your computer.
The photographs accessible are originally empty, as you can see below.
Docker images that are currently available
The Base Image is being downloaded.
The basic IIS image may now be downloaded from Docker Hub. Run docker pull as stated below to do this. Depending on your internet speed, this procedure may take some time to complete.
PS51> docker pull mcr.microsoft.com/windows/servercore/iis
Using the Docker Hub to download an image
Now, run docker images to get the most recent Microsoft Windows Core IIS image for this tutorial.
Docker images that are currently available
Examination of the Dockerfile
You downloaded an existing Dockerfile for this lesson in a previous stage. Let’s take a closer look at what it implies.
In your preferred editor, open the C:ContainersContainer1Dockerfile file. This Dockerfile specifies how the container image will be configured during the construction process.
The in-line comments provide an explanation of what each component of this file accomplishes.
# Specifies that the newest microsoft/iis image will be used as the base image # Used to tell the construction process the base container image to use. # Notice how the naming pattern is “**owner/application name: tag name**” # (seen as microsoft/iis:latest); in our example, the image’s owner is Microsoft, and the application is IIS, with the “latest” tag name indicating that you will retrieve the most current image version available. # retrieved from microsoft/iis:latest Copies the contents of the wwwroot folder to the new container image’s inetpub/wwwroot folder. # Specifies that the WWWroot folder should be copied to the IIS inetpub WWWroot # folder in the container. Because docker already has the logic built-in to reference files and folders relative to the docker file location on your system, you don’t have to supply the entire path to your local # files. Also, since this is a Windows-based container rather than a Linux-based container, # docker will only detect forward slashes for file paths. wwwroot c:/inetpub/wwwroot COPY # To set up the image, run some PowerShell commands within the new container. Remove the default IIS files and build a new # application pool named TestPool using the PowerShell instructions. RUN powershell Remove-Item c:/inetpub/wwwroot/iisstart.htm Remove-Item c:/inetpub/wwwroot/iisstart.png -force RUN powershell RUN powershell with -force RUN powershell New-WebAppPool -Name ‘TestPool’ # Import-Module WebAdministration This line is commented out since the IIS container already has this port open by default. # Used to open TCP port 80 for permitting a http connection to the website. #EXPOSE 80 # Sets the container image’s primary command. When this option is selected, the image will run a service monitor for the w3svc service, and the container will immediately cease executing if the w3svc service stops. Because the # IIS container already has this entrypoint in place by default, this line is commented out. [“C:ServiceMonitor.exe”, “w3svc”] #ENTRYPOINT
Creating a Docker Image
You’ve obtained a basic IIS image and have the Dockerfile ready to launch. It’s now time to use the Dockerfile to create your new Docker image.
Use the docker build “tag” command to create a new image. The picture is created using this command. You can see below that you’re also using the -t ** option to replace the “tag” element in this post. This option enables you to name your new image and reference the Dockerfile by giving the folder path where it is located.
An example of making sure the console is in the C:Containers directory and then creating a new image from the Dockerfile in the C:ContainersContainer1 directory is shown below.
PS51> cd C:Containers PS51> docker build -t container1 .Container1
Once the command is running, you can see its progress as it goes over each line of the docker file:
As the command explores each instruction in the docker filenew, a progress bar is built. Image for Docker
You should now have a brand new Docker image!
To see the images that are available, execute the docker images command. Below is an example of the container1 image that was made.
Docker images that are currently available
Note: The docker build —help command may be used to get more information about the docker command you’re running.
Docker Container Execution
A new picture should be produced at this point. It’s now time to create a container based on that picture. Use the docker run command to start a new container.
The docker run command will start a new Docker container based on the image container1 that you previously produced. Below is an illustration of this.
It’s worth noting that the -d option is utilized. This instructs the Docker runtime to start the image in detached mode and then quit when the container’s root process terminates.
Docker run returns the ID of the container generated after it finishes. This ID is captured in the $containerID variable in the example below so that we may simply access it later.
PS51> $containerID = docker run -d container1 PS51> $containerID
Docker container execution
Run the docker ps command once the container has been started. This command displays which images are presently being used by which containers. Notice how the running picture has an automatically created moniker (in this example, busy habit). To manage the container, this nickname is often used instead of the container ID.
Docker containers that are now running
Code Execution in a Docker Container
A new container is produced from a newly created image. Let’s put the container to work and execute some code. The docker exec command is used to run programs within a Docker container.
Using the command syntax below, run docker exec to inspect PowerShell output for the Get-ChildItem command in the container. This ensures that the Dockerfile’s instructions to delete the default IIS files were followed.
PS51> docker exec $containerID powershell Get-ChildItem c:inetpubwwwroot
The only file that exists is index.html, indicating that the default files have been erased.
In a Docker container, running PowerShell commands
Now, in the container, execute the ipconfig command to get the container image’s local IP address, which you can use to access to the IIS website.
PS51> docker exec $containerID ipconfig
You can see below that ipconfig was ran in the container and returned all of the IP information, exactly as it would on your local machine.
In a Docker container, run ipconfig
Examining the IIS Web Site
It’s now time to show off your hard work! It’s time to check whether the Docker container’s IIS server is correctly providing the index.html page.
Copy the IP4 Address from ipconfig and paste it into your browser’s address bar. If everything is in order, you should see a notice similar to the one below.
In a Docker container, an IIS website is executing.
Examining Docker’s Past
The docker history command is a valuable tool when dealing with Docker containers. The docker history command, although not directly connected to producing an image or container, is a valuable tool for reviewing changes made to the container image.
PS51> docker history container1
As you can see in the screenshot below, the docker history command returns every Dockerfile and PowerShell activity on the container1 container you’ve been dealing with.
Using Docker history to inspect container changes
Cleaning up the Docker Images in Use
To clear out all halted containers on your computer, follow the procedures below. This frees up storage space as well as system resources.
To get a list of the containers operating on your system, use the docker ps command:
Docker containers that are currently available
Now use the docker stop command to stop the running containers:
PS51> docker stop <image nick name: busy_haibt in my case> PS51> docker stop <image nick name: unruffled_driscoll in my case>
Docker container shutdown
Finally, you may use the docker system prune command to permanently remove the halted containers.
PS51> docker system prune
Docker images being removed
Additional Reading
Docker Windows Container on Linux is a container that allows you to create a Docker image with the command “docker build”. This tutorial will show you how to use this command. Reference: docker windows container on linux.
Related Tags
- docker build windows image
- build windows docker image on linux
- docker windows container
- windows dockerfile example
- windows 10 docker image
