Kubernetes: Module 2 - Azure Container Registry (ACR)

Kubernetes: Module 2 - Azure Container Registry (ACR)


Azure Container Registry is a secure fully hosted private Docker registry which we will use to both build & store our application container images

Deploying Azure Container Registry

To create a Azure Container Registry (ACR) instance, pick a name for your ACR, this has to be globally DNS unique (e.g. pick something with your name and the year). We will set this in a Bash variable as we’ll be using it a lot

az acr create -n $ACR_NAME -g kube-lab -l westeurope --sku Standard --admin-enabled true

💬 Note. Sept 2018. We will be using a feature called ACR Build this is currently in preview but now quite stable.

Configure Kubernetes to use ACR

Get the ACR login password and set it in a Bash variable

ACR_PWD=`az acr credential show -n $ACR_NAME -g kube-lab --query "passwords[0].value" -o tsv`

As a sanity check you can display the value of the password using echo $ACR_PWD

In order for the Kubernetes nodes to authenticate with ACR we will set up a Secret in Kubernetes which holds the login details for our registry. There are other ways to authenticate between AKS and ACR however they are slightly more complex, so we’ll not use them in this lab.
📘 ACR and AKS Authentication

Create a secret called acr-auth with this command:

kubectl create secret docker-registry acr-auth --docker-server $ACR_NAME.azurecr.io --docker-username $ACR_NAME --docker-password $ACR_PWD --docker-email ignore@dummy.com

We will use this secret later on

📕 Kubernetes Glossary. A Secret is a Kubernetes object that holds any sensitive information, such as passwords, connection strings or API keys. Setting up Secrets lets us refer to them by name in our deployments and avoids having sensitive details held in plain text

Build container images with ACR

For this section we will be using a brand new feature of Azure Container Registry called “ACR Build”, this allows us to build container images in Azure without need access to a Docker host or having Docker installed locally. It also pushes the resulting images directly into your registry.

We will build our images directly from source. The source of Smilr is held on GitHub in this repository https://github.com/benc-uk/microservices-demoapp

To use ACR Build to run our Docker build task in Azure, we call the az acr build sub-command. The first image we’ll build is for the Smilr data API component, the source Dockerfile is in the node/data-api sub-directory and we’ll tag the resulting image smilr/data-api

az acr build --registry $ACR_NAME -g kube-lab --file node/data-api/Dockerfile --image smilr/data-api https://github.com/benc-uk/microservices-demoapp.git

💬 Note. If you are familiar with the Docker command line and the docker build command you notice some similarity in syntax and approach

💬 Note. If the CLI times out with “no more logs” message you can still view the build logs by running az acr build-task logs -r $ACR_NAME -g kube-lab to check on the progress

That should take about a minute or two to run. After that we’ll build the frontend, the command will be very similar just with a different source file image tag

az acr build --registry $ACR_NAME -g kube-lab --file node/frontend/Dockerfile --image smilr/frontend https://github.com/benc-uk/microservices-demoapp.git

This will take slightly longer but should complete in 3-5 minutes

If you want to double check the images have been built and stored in your registry you can run

az acr repository list -g kube-lab --name $ACR_NAME -o table

End of Module 2

We now have the application images we need built & stored in a private registry. We also have the authorization in place to get AKS to pull/run our images, so we can proceed to look at deploying our microservices into Kubernetes

🡸 Module 1: Deploying Kubernetes
🡺 Module 3: Deploying the Data Layer