ASP.NET Core & Docker
In this guide, I will help you create your first app with ASP.NET Core and Docker. I believe that if you are here you are familiar with ASP.NET, but what is ASP.NET Core? What is Docker? How will they change my work?
ASP.NET Core
ASP .NET Core is a new technology, separated from the already known .NET Framework. Besides, Core works same as ASP.NET, so what are the main reasons for working with it?
- Multi-Platform: The apps we create will work on Windows, Linux and Mac.
- Cloud oriented: .NET Core was designed to work combined with cloud and with this comes a higher performance than the ‘traditional’ ASP.NET.
For installation click here, download the package and install it in a few minutes.
So we can say that this is an improvement from the ASP.NET Freamework where we can work with the cloud and have less problems with other platforms. Now, how can we take more advantage of this? Here is where we meet Docker.
Docker
So, what is Docker and how is this related with the cloud service?
Besides of the official web page description, we can say Docker is a software platform that holds everything as a container. That’s why we see these containers on the top of the whale. So what are this containers?
Containers
Containers are the essential part of Docker, they contain:
- The Operating System
- The app that we are building
- An environment variable
So with this, we can name and work with them. Also, we can freely download these containers on Docker’s official page. We can start running in the environment that we are working on and start working in our app in no time.
In another words, we can think of them as a box with the essential things that we need to start a project and we will have unlimited amount of them so we can start our work with the same base project many times.
For more detailed guide on containers, click here
Images
While we talk about containers there’s a word that comes with it: Images. So, What are images?
Images are the base of the containers which hold files that will run the container. The images can’t turn on or off as well as they can not connect with each other like containers . There are many images on Docker’s official page that you can download. So, you will read, listen and see many times that they are the same thing, but they are surely not.
Here I leave you the official Docker where you can find a more detailed information.
Let’s go deeper in Docker
So this containers are Virtual Machine images? NO
The virtual machines, having an infrastructure, will have a host Operating System and on top of it comes the Hypervisor which can be the virtual machine or the Hyper-V, then they have to work with the Guest Operating System to deliver our app. Also, all of this makes a huge amount of GBs to be working with.
The Containers include the application and all of its dependencies, running as isolated processes in user’s space on the host Operating System.
With Docker we forget about working for different platforms and the Docker Engine makes all the magic for us to forget about the guest OS.
This is getting interesting, isn’t it? Now, if we work with this plus ASP. Net Core there will be a free environment. Let’s try, shall we?
Get ready your Docker
Unlike ASP.NET Core, Docker is a little bit more complicated to install. First of all, we have to download it here.
Now, personally I don’t recommend using the Windows containers just because they didn’t work fine in my computer and by not choosing this option in the settings I could start working in my app. But this doesn’t mean you can’t try and use them. Just keep this in mind if you are using Windows containers.
And if you are on Windows please don’t forget to activate the Hyper-V. Docker will ask you to activate it but if you are distracted remember this.
Now that we have Docker installed we need to get into it by learning some of the basic commands that you may use before starting our project.
Docker Commands
First of all you can use the Command Console or PowerShell if you are in Windows. If you have the possibility to choose use PowerShell as it will be easier to write with than the Command Console.
Let’s have a quick view of the commands, you can write docker in the console and you will get the full list of the commands with their description.
Remember that for cleaning the console you just have to enter cls.
First Page with ASP.NET Core & Docker
Now lets make a simple example.
Open Visual Studio and start a new project ASP.NET Core Web Application. You will see two options: One to Enable Docker Support and another where you can select what container you want to use. I will make the same suggestion than before, use Linux.
Having created the project, you will see a new document called Dockerfile that, as you imagine, is where we will connect with Docker.
Now the start button says Docker. If we click, the button will automatically build an image using our application,creating a container using that same image, and our application will start running inside the container.
We can check all of this with the command ps in Power Shell where we will see the Containers ID and the command images to see the images of our project.
Let’ s Make Something More Difficult
Now we will create two containers and make them connect, all by commands with Docker.
First of all, let’s download the images that we will use.
One option is to go to Docker’s page and download them right there, if not, it can be done from the commands. If you know what image you want to use for your container you have to type docker run imageName, by doing this, docker will see that we don’t have the image so it will start downloading and installing it.
We will download MySQL and WordPress. Another command to download the images is the command Docker pull imageName.
Next step is running the MySQL servers with the command:
docker run — name mysqlname -e MYSQL_ROOT_PASSWORD=abc123 -d mysql:latest
Also, you can see in this example where I remove a container with the command rm and for that I must use the Container ID. At the end, I was checking the images and the containers were all right to continue.
Finally, we will connect the two containers to run the WordPress, first login our account and then with the command:
docker run — name mylocalPage — link mysqlname:mysql -p port -d wordpress
As you can see, the wordpress container is running in the 8080 port and we can see it by using the command port with the Container ID.
Now, we can install WordPress in our container and also there is a connection between the container and the mysql container Data Base.
Personal Opinion
If you followed me from the beginning you can see now the potential of Docker with ASP.NET Core. I think this is a way to have less problems while working on multi-platforms and only thinking about our app. It’s also easy to understand. While doing this I had a ton of problems connecting and downloading, but all of this was solved by different forums that had the same problems as I did with many solutions. Docker is a power full tool and with Core you can make great apps, so don’t give up here.
Finally, the links that helped me making this guide
My job here was to make an introduction, but if you want to know more you can click this links to understand how I worked here. Thanks for reading and keep improving!
