Use OpenFaaS on Azure Kubernetes Service (AKS)

OpenFaaS is a framework that uses containers to build serverless functions. As an open source project, it has gained large-scale adoption within the community. This document details installing and using OpenFaas on an Azure Kubernetes Service (AKS) cluster.

Before you begin

• This article assumes a basic understanding of Kubernetes concepts. For more information, see Kubernetes core concepts for Azure Kubernetes Service (AKS).
• You need an active Azure subscription. If you don't have one, create a free account before you begin.
• You need an AKS cluster. If you don't have an existing cluster, you can create one using the Azure CLI, Azure PowerShell, or Azure portal.
• You need to install the OpenFaaS CLI. For installation options, see the OpenFaaS CLI documentation.

Add the OpenFaaS helm chart repo

1. Navigate to Azure Cloud Shell.

2. Add the OpenFaaS helm chart repo and update to the latest version using the following helm commands.

   helm repo add openfaas https://openfaas.github.io/faas-netes/
   helm repo update
   

Deploy OpenFaaS

As a good practice, OpenFaaS and OpenFaaS functions should be stored in their own Kubernetes namespace.

1. Create a namespace for the OpenFaaS system and functions using the kubectl apply command.

   kubectl apply -f https://raw.githubusercontent.com/openfaas/faas-netes/master/namespaces.yml
   

2. Generate a password for the OpenFaaS UI Portal and REST API using the following commands. The helm chart uses this password to enable basic authentication on the OpenFaaS Gateway, which is exposed to the Internet through a cloud LoadBalancer.

   # generate a random password
   PASSWORD=$(head -c 12 /dev/urandom | shasum| cut -d' ' -f1)
   
   kubectl -n openfaas create secret generic basic-auth \
   --from-literal=basic-auth-user=admin \
   --from-literal=basic-auth-password="$PASSWORD"
   

   Important

   Using a username and password for authentication is an insecure pattern. If you have an OpenFaaS enterprise license, we recommend using Identity and Access Management (IAM) for OpenFaaS instead.

3. Get the value for your password using the following echo command.

   echo $PASSWORD
   

4. Deploy OpenFaaS into your AKS cluster using the helm upgrade command.

   helm upgrade openfaas --install openfaas/openfaas \
       --namespace openfaas  \
       --set basic_auth=true \
       --set functionNamespace=openfaas-fn \
       --set serviceType=LoadBalancer
   

   Your output should look similar to the following condensed example output:

   NAME: openfaas
   LAST DEPLOYED: Tue Aug 29 08:26:11 2023
   NAMESPACE: openfaas
   STATUS: deployed
   ...
   NOTES:
   To verify that openfaas has started, run:
   
   kubectl --namespace=openfaas get deployments -l "release=openfaas, app=openfaas"
   ...
   

5. A public IP address is created for accessing the OpenFaaS gateway. Get the IP address using the kubectl get service command.

   kubectl get service -l component=gateway --namespace openfaas
   

   Your output should look similar to the following example output:

   NAME               TYPE           CLUSTER-IP     EXTERNAL-IP    PORT(S)          AGE
   gateway            ClusterIP      10.0.156.194   <none>         8080/TCP         7m
   gateway-external   LoadBalancer   10.0.28.18     52.186.64.52   8080:30800/TCP   7m
   

6. Test the OpenFaaS system by browsing to the external IP address on port 8080, http://52.186.64.52:8080 in this example, where you're prompted to log in. The default user is admin and your password can be retrieved using echo $PASSWORD.

   

7. Set $OPENFAAS_URL to the URL of the external IP address on port 8080 and log in with the Azure CLI using the following commands.

   export OPENFAAS_URL=http://52.186.64.52:8080
   echo -n $PASSWORD | ./faas-cli login -g $OPENFAAS_URL -u admin --password-stdin
   

Create first function

1. Navigate to the OpenFaaS system using your OpenFaaS URL.

2. Create a function using the OpenFaas portal by selecting Deploy A New Function and search for Figlet.

3. Select the Figlet function, and then select Deploy.

   

4. Invoke the function using the following curl command. Make sure you replace the IP address in the following example with your OpenFaaS gateway address.

   curl -X POST http://52.186.64.52:8080/function/figlet -d "Hello Azure"
   

   Your output should look similar to the following example output:

    _   _      _ _            _
   | | | | ___| | | ___      / \    _____   _ _ __ ___
   | |_| |/ _ \ | |/ _ \    / _ \  |_  / | | | '__/ _ \
   |  _  |  __/ | | (_) |  / ___ \  / /| |_| | | |  __/
   |_| |_|\___|_|_|\___/  /_/   \_\/___|\__,_|_|  \___|
   

Create second function

Configure your Azure Cosmos DB instance

1. Navigate to Azure Cloud Shell.

2. Create a new resource group for the Azure Cosmos DB instance using the az group create command.

   az group create --name serverless-backing --location eastus
   

3. Deploy an Azure Cosmos DB instance of kind MongoDB using the az cosmosdb create command. Replace openfaas-cosmos with your own unique instance name.

   az cosmosdb create --resource-group serverless-backing --name openfaas-cosmos --kind MongoDB
   

4. Get the Azure Cosmos DB database connection string and store it in a variable using the az cosmosdb keys list command. Make sure you replace the value for the --resource-group argument with the name of your resource group, and the --name argument with the name of your Azure Cosmos DB instance.

   COSMOS=$(az cosmosdb keys list \
     --type connection-strings \
     --resource-group serverless-backing \
     --name openfaas-cosmos \
     --output tsv)
   

5. Populate the Azure Cosmos DB with test data by creating a file named plans.json and copying in the following json.

   {
       "name" : "two_person",
       "friendlyName" : "Two Person Plan",
       "portionSize" : "1-2 Person",
       "mealsPerWeek" : "3 Unique meals per week",
       "price" : 72,
       "description" : "Our basic plan, delivering 3 meals per week, which will feed 1-2 people.",
       "__v" : 0
   }
   

Create the function

1. Install the MongoDB tools. The following example command installs these tools using brew. For more installation options, see the MongoDB documentation.

   brew install mongodb
   

2. Load the Azure Cosmos DB instance with data using the mongoimport tool.

   mongoimport --uri=$COSMOS -c plans < plans.json
   

   Your output should look similar to the following example output:

   2018-02-19T14:42:14.313+0000    connected to: localhost
   2018-02-19T14:42:14.918+0000    imported 1 document
   

3. Create the function using the faas-cli deploy command. Make sure you update the value of the -g argument with your OpenFaaS gateway address.

   faas-cli deploy -g http://52.186.64.52:8080 --image=shanepeckham/openfaascosmos --name=cosmos-query --env=NODE_ENV=$COSMOS
   

   Once deployed, your output should look similar to the following example output:

   Deployed. 202 Accepted.
   URL: http://52.186.64.52:8080/function/cosmos-query
   

4. Test the function using the following curl command. Make sure you update the IP address with the OpenFaaS gateway address.

   curl -s http://52.186.64.52:8080/function/cosmos-query
   

   Your output should look similar to the following example output:

   [{"ID":"","Name":"two_person","FriendlyName":"","PortionSize":"","MealsPerWeek":"","Price":72,"Description":"Our basic plan, delivering 3 meals per week, which will feed 1-2 people."}]
   

   Note

   You can also test the function within the OpenFaaS UI:

   

Next steps

Continue to learn with the OpenFaaS workshop, which includes a set of hands-on labs that cover topics such as how to create your own GitHub bot, consuming secrets, viewing metrics, and autoscaling.