Deploying a docker image to Azure
You've made something useful, now make use of it!
UPDATE: In trying to get the container running in AKS, I repeatedly ran up against issues with AKS pulling the image from the the Container Registry. I eventually resolved this by changing the region from northeurope to westeurope. This has been reflected in the az group create ... command below.
Back in October I demonstrated how to dockerize an ASP.NET core application. Now to show how to get that image up to the cloud.
One of the many things good things coming out of Azure is the move away from UI to the command line to setup everything. The Azure CLI tools are special because not only are they available to install locally (PC, macOS and many flavours of linux), but they are also available via the Azure Portal (click the icon circled red on your portal toolbar).
The reason that this is important is that it means that setup and deployment can be scripted and repeatable. If you’re clicking around a UI that is not repeatable, and you are prone to having your cheese moved.
If you aren’t running the CLI tools through the portal the first step is to login with az login, you will then be prompted for your account details.
Next ensure that you are working on the correct subscription: az account show --output table. This will generate some output similar to the following:
EnvironmentName IsDefault Name State TenantId
----------------- ----------- ------------- ------- ------------------------------------
AzureCloud True Pay-As-You-Go Enabled <subscription id>
It is entirely possible that you are on the wrong subscription. Maybe you have an old subscription, or you manage multiple subscriptions through the same account. If the default subscription is incorrect you can change to the correct subscription using the account set command: az account set --subscription "<subscription id/name>". This will set all subsequent commands to run against this subscription.
Next we’re going to create a resource group. According to the Azure Cloud Glossary a Resource Group is:
A container in Resource Manager that holds related resources for an application.
Importantly the Reource Group allows us to direct which data centre our resources should be created in, and then manage those resources en-masse. To create the new Resource Group we use the following command: az group create --name "BlogGroup" --location westeurope. This generates the following output:
{
"id": "/subscriptions/<subscription id>/resourceGroups/BlogGroup",
"location": "westeurope",
"managedBy": null,
"name": "BlogGroup",
"properties": {
"provisioningState": "Succeeded"
},
"tags": null
}
The only part worth breaking out here is the --location parameter. To get a list of the locations available to you use az account list-location, which generates output similar to the following:
[
...,
{
"displayName": "North Europe",
"id": "/subscriptions/<subscription id>/locations/northeurope",
"latitude": "53.3478",
"longitude": "-6.2597",
"name": "northeurope",
"subscriptionId": null
},
...
]
The next step is to create a Container Registry, this is where we will put our Images prior to deployment. The command to do this is: az acr create --name "BlogRegistry" --resource-group "BlogGroup" --sku Basic, and this generates the following output:
{
"adminUserEnabled": false,
"creationDate": "2018-12-19T11:50:20.407592+00:00",
"id": "/subscriptions/<subscription id>/resourceGroups/BlogGroup/providers/Microsoft.ContainerRegistry/registries/BlogRegistry",
"location": "northeurope",
"loginServer": "blogregistry.azurecr.io",
"name": "BlogRegistry",
"provisioningState": "Succeeded",
"resourceGroup": "BlogGroup",
"sku": {
"name": "Basic",
"tier": "Basic"
},
"status": null,
"storageAccount": null,
"tags": {},
"type": "Microsoft.ContainerRegistry/registries"
}
The Container Registry SKUs essentially determine how much you pay for the privilege. The Basic registry is the most appropriate for this tutorial.
The next step is to log docker into the Azure Container Registry, this is done with the command az acr login --name BlogRegistry.
N.B. If you try and run this command in the portal CLI you will receive this error:
This command requires running the docker daemon, which is not supported in Azure Cloud Shell.
This command, and the next two commands to upload your docker image need to be run on your machine.
To get our image in to the registry we need to do two more commands, tag and push. But the tag in particular needs several pieces of information. The first piece of information is loginServer that is retured from az acr create. The other piece of information is the image name, you can find this through docker image ls, on my machine this is the list that is generated:
REPOSITORY TAG IMAGE ID CREATED SIZE
<none> <none> 5353701500cc 6 days ago 1.84GB
blog.app 1 c57a36e90398 6 days ago 264MB
<none> <none> 8fe537899022 6 days ago 1.84GB
microsoft/dotnet sdk ea6f66a1e7b7 7 days ago 1.73GB
microsoft/dotnet aspnetcore-runtime 41db56126a6d 7 days ago 260MB
And it is the blog.app image that I’m interested in. The command to correctly tag the image is docker tag blog.app:1 blogregistry.azurecr.io/blog.app:1. After executing this command when we execute docker image ls we now get this output:
REPOSITORY TAG IMAGE ID CREATED SIZE
<none> <none> 5353701500cc 6 days ago 1.84GB
blogregistry.azurecr.io/blog.app 1 c57a36e90398 6 days ago 264MB
blog.app 1 c57a36e90398 6 days ago 264MB
<none> <none> 8fe537899022 6 days ago 1.84GB
microsoft/dotnet sdk ea6f66a1e7b7 7 days ago 1.73GB
microsoft/dotnet aspnetcore-runtime 41db56126a6d 7 days ago 260MB
Notice that there are two blog.app images, but one is shown as belonging to blogregistry.azurecr.io.
To actually get the image in to the ACR we need to docker push blogregistry.azurecr.io/blog.app:1. This will take a few moments, depending on the upstream speed of your internet connection. Once the app has completed uploading you can verify that it has pushed the image up by using this command: az acr repository list --name BlogRegistry. For me the output is:
[
"blog.app"
]
The image is now available in the cloud to be deployed.