Using Containers in Azure

01 Aug 2020 - Sanjeev

Skills Measured

  1. Create container images for solutions by using Docker
  2. Publish an image to the Azure Container Registry
  3. Run containers by using Azure Container Instance

We will do the following to understand different concepts involved to learn the skill set being measured. Below code assumes windows host machine with docker desktop installed.

Create and publish a .Net Core WebApi project

Run the below code from a command line window

mkdir webapis Create a working directory to host the project

cd webapis make that directory as the working directory

Run the command dotnet new webapi to scaffold a new ASP.NET WebAPI Project

Create webapi result

Execute dotnet run to run the application

run webapi project locally

Application is now running on ports 5000 (http) and 5001 (https). Confirm that the application is running by browsing to url https://localhost:5001/WeatherForecast

webapi output in browser

Package and Push the app as a docker Image to dockerhub

publish the application to out directory using command dotnet publish -c Release -o out

webapi project published

Within the project directory, create a file with name Dockerfile without any extension. Use the command echo FROM > Dockerfile to create a new file. Copy the below content in that file.

  
    FROM mcr.microsoft.com/dotnet/core/aspnet:3.1
    # Use the base image of ASP.Net 3.1
    WORKDIR /app
    # Set app as the working directory
    COPY /out .
    # Copy the content from the published directory
    EXPOSE 80
    EXPOSE 443
    # Expose ports 80 (http) and 443 (https)
    ENTRYPOINT ["dotnet", "webapis.dll"]
    # Starting command for this image

Run the command docker build -f Dockerfile -t webapis:v1 to build the docker image of the application with tag v1

Build docker image of the application

Run the command docker images to make sure you have the container in the local repo

Verifiy the image in local repo

Run the image using the command docker run --rm -it -p 5000:80 -p 5001:443 -e ASPNETCORE_URLS="https://+;http://+" -e ASPNETCORE_HTTPS_PORT=8001 -e ASPNETCORE_Kestrel__Certificates__Default__Password="crypticpassword" -e ASPNETCORE_Kestrel__Certificates__Default__Path=/https/aspnetapp.pfx -v %USERPROFILE%\.aspnet\https:/https/ webapis:v1 and run command docker ps to check if the container is running.

Run the docker image

Navigating to the url https://localhost:5001/WeatherForecast should give the similar out as before

webapi output in browser

Execute command docker tag webapis:v1 <docker account name>/webapis:v1 in preparationg for moving the image to dockerhub. Run command docker push <docker account name>/webapis:v1

webapi output in browser

Create an Azure WebApp and deploy the image

Navigate to Azure Shell and sign-in.

  
    let randomNum=$RANDOM*$RANDOM
    # Generate a random number to use so that we do not have to revisit the names used in the sample
    resourceGroupName="lab-containers"$randomNum"-Group"
    # Resource group name
    az configure --defaults location=eastus
    az configure --defaults group=$resourceGroupName
    # We do not have to pass the location and resource group attribute once configured so the length of the command becomes small
    az group create --name $resourceGroupName
    #Create the resource group
    appServiceName="appService"$randomeNum
    az appservice plan create --name $appServiceName --sku Free --is-linux
    #Create a linux free app service plan
    az webapp create --name webapp$randomNum -p $appServiceName -i <docker account name>/webapis:v1
    #Creates a web application using the docker image. Replace the docker account name in the above command.
    az webapp show --name webapp$randomNum --query enabledHostNames[0]
    # Execute to get the url to the website

Navigating to the /WeatherForecast, should get the similar response from the API

API response from Azure webapp

Create and push the docker image to Azure container registry

  
    #Create an instance of Azure Container Registry with admin user
    az acr create --name acr$randomNum --sku Basic --admin-enabled --query loginServer
    #Above command returns the login server uri. Execute below command will give the password for the admin user
    az acr credential show --name acr$randomNum --query passwords[0].value

From your local machine, execute below docker commands docker login <acr login server>.azurecr.io to upload the image to acr

Login to ACR

Tag the image for acr by executing the command docker tag webapis:v1 <acr login server>.azurecr.io/webapis:v1 and push the image to the registry by executing the command docker push <acr login server>.azurecr.io/webapis:v1

Push image to ACR

Deploy the image from Azure Container Registry to WebApp created earlier

Lets make some change to the code so that we are sure we are deploying the new image only available from ACR image registry. Update the WeatherForecast class with new attributing ReportingTime as public DateTime ReportingTime => DateTime.Now;. This would provide when the weather was reported.Execute below commands to build and push the image to acr.

  
    dotnet build
    dotnet publish -c Release -o out
    docker build -f Dockerfile -t webapis:v2 .
    docker tag webapis:v2 <acr login server>.azurecr.io/webapis:v2
    docker push <acr login server>.azurecr.io/webapis:v2
    az webapp config container set --name webapp$randomNum --docker-custom-image-name acr$randomNum.azurecr.io/webapis:v2 --docker-registry-server-url https://acr$randomNum.azurecr.io --docker-registry-server-user acr$randomNum --docker-registry-server-password <Password for admin user in acr >

When navigate to https://<Webapp url>/WeatherForecast we should see the updated response

Response with Reported time

Create and deploy the image from Azure Container Registry to Azure Container Instance

Create and deploy the container with az container create --name aci$randomNum --os-type Linux --cpu 2 --image acr$randomNum.azurecr.io/webapis:v2 --ports 80 --ip-address public --dns-name-label aci$randomNum

Navigate to url http://.eastus.azurecontainer.io/WeatherForecast to see our familiar output. Please note we are using http not https here.

References


Do let me know if you have any clarification/suggestion on this post. I will be happy to know your feedback!