The newest LTS version of Ubuntu is scheduled to release on April 23. Once it’s released, upgrading is as easy as running a few commands. In this article, we’ll walk through the process of updating the current system and then performing the upgrade.
Before you upgrade, make sure your system is as up to date as possible. Do this by running the follwing commands:
If you receive a No new release found message, it means the upgrade hasn’t been made available to you. It’s been noted that the upgrade path from 19.10 will not be enabled until a few days after release, and the upgrade from 18.04 LTS will not be enabled until a few days after the 20.04.1 release expected in late July. However, you can force the upgrade at your own risk by using the -d flag.
I was all geared up to explore unit testing in Angular this morning–something I’ve been putting off learning for quite some time–and quickly hit an problem. I started by installing Angular CLI using apt install ng-common, but trying to use the Angular CLI’s ng command was launching Emacs!
It took me a minute to figure this out, and here’s what it took. First, I uninstalled:
sudo apt remove ng-common
Next, I installed using npm:
sudo npm install -g @angular/cli
This was common how-to-fix-it advice, but this didn’t resolve the problem for me. At this point ng was no longer launching an editor, but instead it was an unrecognized command. Luckily, I found the solution here.
I noticed in the install output that the bin location was listed. I was able to verify where the ng binary was located and add an alias. After that, ng --version worked successfully.
Here’s the alias I added to ~/.bashrc:
alias ng='/usr/local/lib/node_modules/@angular/cli/bin/ng'
In my last article, I wrote about how to create a single-page Angular app using the .NET Core CLI, create a Docker image, and run it as a container in about 4 steps that take just minutes to execute. By modifying a single line in your Dockerfile, you can target the 32-bit ARM architecture needed to run the image as a container on a Raspberry Pi.
Here’s the one line that needs to change in the Dockerfile to make it runnable on ARM32 (old line is commented for reference):
# FROM mcr.microsoft.com/dotnet/core/aspnet:3.1 AS base
FROM mcr.microsoft.com/dotnet/core/aspnet:3.1.2-buster-slim-arm32v7 AS base
WORKDIR /app
EXPOSE 80
EXPOSE 443
FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build
WORKDIR /src
COPY ["my-app.csproj", "./"]
RUN dotnet restore "./my-app.csproj"
COPY . .
WORKDIR "/src/."
RUN dotnet build "my-app.csproj" -c Release -o /app/build
RUN apt-get update && \
apt-get install -y wget && \
apt-get install -y gnupg2 && \
wget -qO- https://deb.nodesource.com/setup_10.x | bash - && \
apt-get install -y build-essential nodejs
FROM build AS publish
RUN dotnet publish "my-app.csproj" -c Release -o /app/publish
FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "my-app.dll"]
Note that the official list of available tags for different architectures can be found here. Consult this list to determine if newer images are available.
That’s it, though. Create your image, push it to Docker Hub, pull it on your Raspberry Pi, and run it just as you would locally. If you haven’t used Docker Hub before, you’ll need to login and create a repository. Check out the Docker Hub Quickstart for help. You may also need to run docker login on both machines to access your new repo.
# dev machine
docker build -t <dockerID>/repo .
docker push <dockerID>/repo
# raspberry pi
docker pull <dockerID>/repo
docker run -d -p 5000:80 <dockerID>/repo
The default dotnet new Angular app running locally on Raspberry Pi.
In this article, I’ll demonstrate how to create an ASP.NET Core Angular single-page application using the .NET Core CLI, create a Docker image, and run it as a container. The entire process is just 4 steps, each of which takes about a minute to perform–although creating the Docker image takes a couple minutes to complete. Note, also, that these same steps work from both Linux and Windows.
Create Angular application
Create Dockerfile
Create Docker image
Run container
Before you start, make sure you have the following prerequisites installed.
.NET Core SDK
Visual Studio Code with Docker extension
Docker
Installation can be verified by running these commands:
We begin by creating our Angular application using the dotnet new command and specifying the angular template. The -o argument will cause the new project to be created in a sub-folder named my-app. This will create a .NET Core ASP.NET project with an Angular app in its ClientApp folder. After running the command, go into the new directory and launch Visual Studio Code.
dotnet new angular -o my-app
cd my-app
code .
Add Docker Files
With the Docker extension for VS Code installed, you can add Docker files easily via the command palette. Open the command palette using ctrl+shift+P or View > Command Palette menu options, and run the command Docker: Add Docker Files to Workspace. (Tip: type “docker” to filter commands.)
Selecting the command will ask you a series of questions:
Application Platform: ASP.NET Core
Operating System: Linux
What port(s) does your app listen on? 80, 443
If you’re running Docker on Windows, it’s important to make sure Docker is configured to run the right type of containers (Windows vs Linux). I answered “Linux” above, and I can confirm that my Docker for Windows is configured to run Linux containers by clicking the Docker icon in my system tray, as shown in the screenshot below. It shows “Switch to Windows containers” which means it’s currently using Linux containers. It’s fine to use Windows containers, too, but you’ll need to adjust installation instructions for NodeJS in the Dockerfile further down.
Once you’ve answered the Docker extention’s questions, a Dockerfile is generated. One modification is needed to also install NodeJS for our client app. The lines needed to do this are highlighted in the complete Dockerfile below.
FROM mcr.microsoft.com/dotnet/core/aspnet:3.1 AS base
WORKDIR /app
EXPOSE 80
EXPOSE 443
FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build
WORKDIR /src
COPY ["my-app.csproj", "./"]
RUN dotnet restore "./my-app.csproj"
COPY . .
WORKDIR "/src/."
RUN dotnet build "my-app.csproj" -c Release -o /app/build
RUN apt-get update && \
apt-get install -y wget && \
apt-get install -y gnupg2 && \
wget -qO- https://deb.nodesource.com/setup_10.x | bash - && \
apt-get install -y build-essential nodejs
FROM build AS publish
RUN dotnet publish "my-app.csproj" -c Release -o /app/publish
FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "my-app.dll"]
Build the Image
When you’re done editing your Dockerfile in VS Code, save changes and head back to the command line. Run the following command to build your image:
docker build -t my-app .
Verify that the image was created by running another command:
docker image ls my-app
Run a Container
Now we’ll use the docker run command to run a container using our image. We’ll specify two arguments: -d to run in detached mode and -p to map ports on the local machine to the container.
docker run -d -p 5000:80 my-app
Verify that the app is running by browsing to the localhost:5000:
I have a complicated relationship with Linux. Every few years, I get nostalgic about my Solaris days back in college. So I build a machine, struggle through getting all the hardware & whatnot working, and invest tons of time trying to get the Windows apps I know & love running on it. Then I give up and go back to Windows.
And that’s about where I’m at now, in the nostalgia/fascination stage with fantasies of leaving my familiar Microsoft pastures. At work, we’re moving more & more toward containerization and Kubernetes with the goal of reducing cost by hosting services on Linux. Maybe its relevance to work will give the effort more legs this time?
So I embarked on the journey (again) and have been pleased with how much the experience has matured. Doing a clean install of Ubuntu on my old laptop was completely painless. I didn’t need to do any special setup or troubleshooting to get hardware running. In fact, it was 100% as easy as installing Windows, which I was forced to do a few weeks earlier presumably due to some botched updates that had me blue-screening every few minutes.
Keeping the momentum going, I jumped right into installing .NET Core and setting up Visual Studio Code. The whole thing–from beginning to end; from formatting and installing the OS to running my first console app–took about an hour.
It was easy enough that just about anybody capable of doing a clean OS install should be able to manage it. In fact, let’s go through all the steps, right now! I’ll walk you through what’s needed from installing the OS, .NET Core, and VS Code all the way through to creating and running a new project.
Alternatively, you could use a virtual machine. Since I’m retracing my own steps as I write this, I’m using VirtualBox which is freely available to everybody–so no excuses about not having a spare computer laying around! If you’re going this route, download VirtualBox, fire it up, and create a new virtual machine. For reference, I picked Linux/Ubuntu (64-bit) and used all defaults*. You still need to download the Ubuntu ISO, and select it as the boot media the first time you start the VM.
*My VM kept hanging during install until I increased memory from the default 1024 MB to 2048 MB.
Alright, now we’ve got our Linux machine running, and it’s time to install .NET Core. Follow Microsoft’s instructions to install the .NET Core SDK, or open a terminal and run the following commands:
That’s it! Who’s ready to run some code? Use the dotnet CLI to create a new console app, open the code in VS Code, and run it using F5 or Debug > Start Debugging. (If it’s your first run with the C# extensions installed, you may need to wait while it downloads dependencies.) VS Code will ask you which environment to use; pick .NET Core to add a launch.json file which tells VS Code how to run your app.
dotnet new console -o HelloConsole
cd HelloConsole
code .
And there you have it. Reproducing the setup on a VM, I was able to download the Ubuntu ISO, create a clean install, install .NET Core SDK & runtime along with VS Code, and create & run a new C# console app in under an hour. Not bad!