Kubernetes on Microsoft Azure Kubernetes Service (AKS)¶

You can create a Kubernetes cluster either through the Azure portal website, or using the Azure command line tools.

This page describes the commands required to setup a Kubernetes cluster using the command line. If you prefer to use the Azure portal see the Azure Kubernetes Service quickstart.

Prepare your Azure shell environment. You have two options, one is to use the Azure interactive shell, the other is to install the Azure command-line tools locally. Instructions for each are below.
- Using the Azure interactive shell. The Azure Portal contains an interactive shell that you can use to communicate with your Kubernetes cluster. To access this shell, go to portal.azure.com and click on the button below.
Note
- If you get errors like could not retrieve token from local cache, try refreshing your browser window.
- The first time you do this, you’ll be asked to create a storage account where your shell filesystem will live.
- Install command-line tools locally. You can access the Azure CLI via a package that you can install locally.
  
  To do so, first follow the installation instructions in the Azure documentation. Then run the following command to connect your local CLI with your account:
```
az login
```
  You’ll need to open a browser and follow the instructions in your terminal to log in.
Activate the correct subscription. Azure uses the concept of subscriptions to manage spending. You can get a list of subscriptions your account has access to by running:
```
az account list --refresh --output table
```
Pick the subscription you want to use for creating the cluster, and set that as your default. If you only have one subscription you can ignore this step.
```
az account set --subscription <YOUR-CHOSEN-SUBSCRIPTION-NAME>
```
Create a resource group. Azure uses the concept of resource groups to group related resources together. We need to create a resource group in a given data center location. We will create computational resources within this resource group.
```
az group create \
              --name=<RESOURCE-GROUP-NAME> \
              --location=centralus \
              --output table
```
where:
- --name specifies the name of your resource group. We recommend using something that uniquely identifies this hub. For example, if you are creating a resource group for UC Berkeley’s 2018 Spring Data100 Course, you may give it a <RESOURCE-GROUP-NAME> of ucb_2018sp_data100_hub.
- --location specifies the location of the data center you want your resource to be in. In this case, we used the centralus location. For other options, see the Azure list of locations that support AKS.
- --output table specifies that the output should be in human readable format, rather than the default JSON output. We shall use this with most commands when executing them by hand.
Note

Consider setting a cloud budget for your Azure account in order to make sure you don’t accidentally spend more than you wish to.
Choose a cluster name.

In the following steps we’ll run commands that ask you to input a cluster name. We recommend using something descriptive and short. We’ll refer to this as <CLUSTER-NAME> for the remainder of this section.

The next step will create a few files on your filesystem, so first create a folder in which these files will go. We recommend giving it the same name as your cluster:
```
mkdir <CLUSTER-NAME>
cd <CLUSTER-NAME>
```
Create an ssh key to secure your cluster.
```
ssh-keygen -f ssh-key-<CLUSTER-NAME>
```
It will prompt you to add a password, which you can leave empty if you wish. This will create a public key named ssh-key-<CLUSTER-NAME>.pub and a private key named ssh-key-<CLUSTER-NAME>. Make sure both go into the folder we created earlier, and keep both of them safe!

Note

This command will also print out something to your terminal screen. You don’t need to do anything with this text.
Create a virtual network and sub-network.

Kubernetes does not by default come with a controller that enforces networkpolicy resources. networkpolicy resources are important as they define how Kubernetes pods can securely communicate with one another and the outside sources, for example, the internet.

To enable this in Azure, we must first create a Virtual Network with Azure’s own network policies enabled.

This section of the documentation is following the Microsoft Azure tutorial on creating an AKS cluster and enabling network policy, which includes information on using Calico network policies.
```
az network vnet create \
    --resource-group <RESOURCE-GROUP-NAME> \
    --name <VNET-NAME> \
    --address-prefixes 10.0.0.0/8 \
    --subnet-name <SUBNET-NAME> \
    --subnet-prefix 10.240.0.0/16
```
where:
- --resource-group is the ResourceGroup you created
- --name is the name you want to assign to your virtual network, for example, hub-vnet
- --address-prefixes are the IP address prefixes for your virtual network
- --subnet-name is your desired name for your subnet, for example, hub-subnet
- --subnet-prefixes are the IP address prefixes in CIDR format for the subnet
We will now retrieve the application IDs of the VNet and subnet we just created and save them to bash variables.
```
VNET_ID=$(az network vnet show \
    --resource-group <RESOURCE-GROUP-NAME> \
    --name <VNET-NAME> \
    --query id \
    --output tsv)
SUBNET_ID=$(az network vnet subnet show \
    --resource-group <RESOURCE-GROUP-NAME> \
    --vnet-name <VNET-NAME> \
    --name <SUBNET-NAME> \
    --query id \
    --output tsv)
```
We will create an Azure Active Directory (Azure AD) service principal for use with the cluster, and assign the Contributor role for use with the VNet. Make sure SERVICE-PRINCIPAL-NAME is something recognisable, for example, binderhub-sp.
```
SP_PASSWD=$(az ad create-for-rbac \
    --name <SERVICE-PRINCIPAL-NAME> \
    --role Contributor \
    --scopes $VNET_ID \
    --query password \
    --output tsv)
SP_ID=$(az ad sp show \
    --id http://<SERVICE-PRINCIPAL-NAME> \
    --query appId \
    --output tsv)
```
Warning

You will need Owner role on your subscription for this step to succeed.
Create an AKS cluster.

The following command will request a Kubernetes cluster within the resource group that we created earlier.
```
az aks create \
    --name <CLUSTER-NAME> \
    --resource-group <RESOURCE-GROUP-NAME> \
    --ssh-key-value ssh-key-<CLUSTER-NAME>.pub \
    --node-count 3 \
    --node-vm-size Standard_D2s_v3 \
    --service-principal $SP_ID \
    --client-secret $SP_PASSWD \
    --dns-service-ip 10.0.0.10 \
    --docker-bridge-address 172.17.0.1/16 \
    --network-plugin azure \
    --network-policy azure \
    --service-cidr 10.0.0.0/16 \
    --vnet-subnet-id $SUBNET_ID \
    --output table
```
where:
- --name is the name you want to use to refer to your cluster
- --resource-group is the ResourceGroup you created
- --ssh-key-value is the ssh public key created
- --node-count is the number of nodes you want in your Kubernetes cluster
- --node-vm-size is the size of the nodes you want to use, which varies based on what you are using your cluster for and how much RAM/CPU each of your users need. There is a list of all possible node sizes for you to choose from, but not all might be available in your location. If you get an error whilst creating the cluster you can try changing either the region or the node size.
- --service-principal is the application ID of the service principal we created
- --client-secret is the password for the service principal we created
- --dns-service-ip is an IP address assigned to the Kubernetes DNS service
- --docker-bridge-address is a specific IP address and netmask for the Docker bridge, using standard CIDR notation
- --network-plugin is the Kubernetes network plugin to use. In this example, we have used Azure’s own implementation.
- --network-policy is the Kubernetes network policy to use. In this example, we have used Azure’s own implementation.
- --service-cidr is a CIDR notation IP range from which to assign service cluster IPs
- vnet-subnet-id is the application ID of the subnet we created
- This command will install the default version of Kubernetes. You can pass --kubernetes-version to install a different version.
This should take a few minutes and provide you with a working Kubernetes cluster!
If you’re using the Azure CLI locally, install kubectl, a tool for accessing the Kubernetes API from the commandline:
```
az aks install-cli
```
Note: kubectl is already installed in Azure Cloud Shell.
Get credentials from Azure for kubectl to work:
```
az aks get-credentials \
             --name <CLUSTER-NAME> \
             --resource-group <RESOURCE-GROUP-NAME> \
             --output table
```
where:
- --name is the name you gave your cluster
- --resource-group is the ResourceGroup you created
This automatically updates your Kubernetes client configuration file.
Check if your cluster is fully functional
```
kubectl get node
```
The response should list three running nodes and their Kubernetes versions! Each node should have the status of Ready, note that this may take a few moments.

Note

If you create the cluster using the Azure Portal you must enable RBAC. RBAC is enabled by default when using the command line tools.

Congrats. Now that you have your Kubernetes cluster running, it’s time to begin Setup JupyterHub.

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