azure-votes-postgresql

Azure PostgreSQL Votes Demo App

About this demo

In this demo, we will walk through creating an Azure Postgres Flexible Server and Postgres database. We will create a simple application which records votes and stores them in the database.

Prerequisites

1. An Azure subscription to create Azure resources under.
2. A Kubernetes cluster (at least version 1.21) created and running, and kubectl configured to talk to it. (You can check your cluster version with kubectl version.) This could be a local Kind cluster or an Azure Kubernetes Service cluster running in your subscription.
3. Azure Service Operator set up and running in your cluster of choice. Follow the ASO v2 installation instructions and ensure that you can create and delete a simple ResourceGroup as shown in the usage example.

Demo

Step 1: Create environment variables to hold a few key values

export SERVER=asodemo-postgres
export USERNAME=asoadmin
export PASSWORD=<yourpassword>

Step 2: Create your Azure Resources

We use envsubst here as a quick and simple way to do basic variable replacement.

envsubst < manifests/postgres-votes-demo.yaml | kubectl apply -f -

This command will create a namespace, along with an Azure ResourceGroup along with a PostgreSQL FlexibleServer, FlexibleServerDatabase and FlexibleServerFirewallRule. It also creates a Secret for use later in binding some important connection information into our votes app.

Note: In a future iteration of ASO, the username and password fields of the FlexibleServer will be specified via a linked Secret. See #1471 for more details.

Step 3: Check the status of your resources and wait for them to finish provisioning

watch kubectl get resourcegroups,flexibleservers,flexibleserversdatabases,flexibleserversfirewallrules -n asodemo

It may take a few minutes for the FlexibleServer to successfully deploy, during which time you will see:

NAME               READY   REASON        MESSAGE
asodemo-postgres   False   Reconciling   The resource is in the process of being reconciled by the operator

The FlexibleServersDatabase cannot be successfully deployed until the FlexibleServer it resides in has finished deploying. While the FlexibleServer is being deployed, you will see the database is not deployed and has the following message. This is ok! Once the FlexibleServer has been successfully created in Azure this will resolve itself automatically.

NAME       READY   REASON             MESSAGE
sampledb   False   ResourceNotFound   The specified resource asodemo-postgres was not found.

Step 4: Create a deployment with a single pod running the Azure PostgreSQL Votes App

kubectl apply -f manifests/deploy.yaml

Ensure that the pod is running:

kubectl get pods -n asodemo

Step 5: Port forward to the pod

kubectl port-forward -n asodemo deployment/azure-votes-postgresql-deployment 8080:8080

Step 6: Vote!

Visit localhost:8080 to vote.

Step 7: (Optional) look at the data in the database

You can use the psql command line to look at the "votes" table.

psql -h $SERVER.postgres.database.azure.com -p 5432 -U $USERNAME votedb

SELECT * FROM votes;

Step 7: Delete the asodemo namespace

You don't need to delete the Azure resources individually. The Kubernetes ownership model ensures that when the namespace containing the resources is deleted, the delete is propagated to all resources.

kubectl delete namespace asodemo

Build the Docker Image

We publish the docker image for you, but if you'd like to build it yourself, run the following commands.

docker build -t your_registry.com/your_org_or_user/postgresql_azure_votes:1
docker push your_registry.com/your_org_or_user/postgresql_azure_votes:1