Run full-stack workloads at scale on GKE


This tutorial shows you how to run a web application that is backed by a highly-available relational database at scale in Google Kubernetes Engine (GKE).

The sample application used in this tutorial is Bank of Anthos, an HTTP-based web application that simulates a bank's payment processing network. Bank of Anthos uses multiple services to function. This tutorial focuses on the website frontend and the relational PostgreSQL databases that backs the Bank of Anthos services. To learn more about Bank of Anthos, including its architecture and the services it deploys, refer to Bank of Anthos on GitHub.

Objectives

  • Create and configure a GKE cluster.
  • Deploy a sample web application and a highly-available PostgreSQL database.
  • Configure autoscaling of the web application and the database.
  • Simulate spikes in traffic using a load generator.
  • Observe how the services scale up and down.

Costs

In this document, you use the following billable components of Google Cloud:

To generate a cost estimate based on your projected usage, use the pricing calculator. New Google Cloud users might be eligible for a free trial.

When you finish the tasks that are described in this document, you can avoid continued billing by deleting the resources that you created. For more information, see Clean up.

Before you begin

  1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.
  2. Install the Google Cloud CLI.
  3. To initialize the gcloud CLI, run the following command:

    gcloud init
  4. Create or select a Google Cloud project.

    • Create a Google Cloud project:

      gcloud projects create PROJECT_ID
    • Select the Google Cloud project that you created:

      gcloud config set project PROJECT_ID
  5. Make sure that billing is enabled for your Google Cloud project.

  6. Enable the GKE API:

    gcloud services enable container.googleapis.com
  7. Install the Google Cloud CLI.
  8. To initialize the gcloud CLI, run the following command:

    gcloud init
  9. Create or select a Google Cloud project.

    • Create a Google Cloud project:

      gcloud projects create PROJECT_ID
    • Select the Google Cloud project that you created:

      gcloud config set project PROJECT_ID
  10. Make sure that billing is enabled for your Google Cloud project.

  11. Enable the GKE API:

    gcloud services enable container.googleapis.com
  12. Install the Helm CLI.

Prepare the environment

  1. Clone the sample repository used in this tutorial:

    git clone https://github.com/GoogleCloudPlatform/bank-of-anthos.git
    cd bank-of-anthos/
    
  2. Set environment variables:

    PROJECT_ID=PROJECT_ID
    GSA_NAME=bank-of-anthos
    GSA_EMAIL=bank-of-anthos@${PROJECT_ID}.iam.gserviceaccount.com
    KSA_NAME=default
    

    Replace PROJECT_ID with your Google Cloud project ID.

Set up the cluster and service accounts

  1. Create a cluster:

    gcloud container clusters create-auto bank-of-anthos --region=us-central1
    

    The cluster might take up to five minutes to start.

  2. Create an IAM service account:

    gcloud iam service-accounts create bank-of-anthos
    
  3. Grant access to the IAM service account:

    gcloud projects add-iam-policy-binding PROJECT_ID \
      --role roles/cloudtrace.agent \
      --member "serviceAccount:bank-of-anthos@PROJECT_ID.iam.gserviceaccount.com"
    gcloud projects add-iam-policy-binding PROJECT_ID \
      --role roles/monitoring.metricWriter \
      --member "serviceAccount:bank-of-anthos@PROJECT_ID.iam.gserviceaccount.com"
    gcloud iam service-accounts add-iam-policy-binding "bank-of-anthos@PROJECT_ID.iam.gserviceaccount.com" \
      --role roles/iam.workloadIdentityUser \
      --member "serviceAccount:PROJECT_ID.svc.id.goog[default/default]"
    

    This step grants the following access:

    • roles/cloudtrace.agent: Write trace data such as latency information to Trace.
    • roles/monitoring.metricWriter: Write metrics to Cloud Monitoring.
    • roles/iam.workloadIdentityUser: Allow a Kubernetes service account to use workload identity federation for GKE to act as the IAM service account.
  4. Configure the default Kubernetes service account in the default namespace to act as the IAM service account that you created:

    kubectl annotate serviceaccount default \
        iam.gke.io/gcp-service-account=bank-of-anthos@PROJECT_ID.iam.gserviceaccount.com
    

    This allows Pods that use the default Kubernetes service account in the default namespace to access the same Google Cloud resources as the IAM service account.

Deploy Bank of Anthos and PostgreSQL

In this section, you install Bank of Anthos and a PostgreSQL database in highly-available (HA) mode, which lets you autoscale replicas of the database server. If you want to view the scripts, Helm chart, and Kubernetes manifests used in this section, check the Bank of Anthos repository on GitHub.

  1. Deploy the database schema and a data definition language (DDL) script:

    kubectl create configmap initdb \
        --from-file=src/accounts/accounts-db/initdb/0-accounts-schema.sql \
        --from-file=src/accounts/accounts-db/initdb/1-load-testdata.sql \
        --from-file=src/ledger/ledger-db/initdb/0_init_tables.sql \
        --from-file=src/ledger/ledger-db/initdb/1_create_transactions.sh
    
  2. Install PostgreSQL using the sample Helm chart:

    helm repo add bitnami https://charts.bitnami.com/bitnami
    helm install accounts-db bitnami/postgresql-ha \
        --version 10.0.1 \
        --values extras/postgres-hpa/helm-postgres-ha/values.yaml \
        --set="postgresql.initdbScriptsCM=initdb" \
        --set="postgresql.replicaCount=1" \
        --wait
    

    This command creates a PostgreSQL cluster with a starting replica count of 1. Later in this tutorial, you'll scale the cluster based on incoming connections. This operation might take ten minutes or more to complete.

  3. Deploy Bank of Anthos:

    kubectl apply -f extras/jwt/jwt-secret.yaml
    kubectl apply -f extras/postgres-hpa/kubernetes-manifests
    

    This operation might take a few minutes to complete.

Checkpoint: Validate your setup

  1. Check that all Bank of Anthos Pods are running:

    kubectl get pods
    

    The output is similar to the following:

    NAME                                  READY   STATUS
    accounts-db-pgpool-57ffc9d685-c7xs8   3/3     Running
    accounts-db-postgresql-0              1/1     Running
    balancereader-57b59769f8-xvp5k        1/1     Running
    contacts-54f59bb669-mgsqc             1/1     Running
    frontend-6f7fdc5b65-h48rs             1/1     Running
    ledgerwriter-cd74db4cd-jdqql          1/1     Running
    pgpool-operator-5f678457cd-cwbhs      1/1     Running
    transactionhistory-5b9b56b5c6-sz9qz   1/1     Running
    userservice-f45b46b49-fj7vm           1/1     Running
    
  2. Check that you can access the website frontend:

    1. Get the external IP address of the frontend service:

      kubectl get ingress frontend
      

      The output is similar to the following:

      NAME       CLASS    HOSTS   ADDRESS         PORTS   AGE
      frontend   <none>   *       203.0.113.9     80      12m
      
    2. In a browser, go to the external IP address. The Bank of Anthos sign in page displays. If you're curious, explore the application.

      If you get a 404 error, wait a few minutes for the microservices to provision and try again.

Autoscale the web app and PostgreSQL database

GKE Autopilot autoscales the cluster compute resources based on the number of workloads in the cluster. To automatically scale the number of Pods in the cluster based on resource metrics, you must implement Kubernetes horizontal Pod autoscaling. You can use the built-in Kubernetes CPU and memory metrics or you can use custom metrics such as HTTP requests per second or the quantity of SELECT statements, taken from Cloud Monitoring.

In this section, you do the following:

  1. Configure horizontal Pod autoscaling for the Bank of Anthos microservices using both built-in metrics and custom metrics.
  2. Simulate load to the Bank of Anthos application to trigger autoscaling events.
  3. Observe how the number of Pods and the nodes in your cluster automatically scale up and down in response to your load.

Set up custom metrics collection

To read custom metrics from Monitoring, you must deploy the Custom Metrics - Stackdriver Adapter adapter in your cluster.

  1. Deploy the adapter:

    kubectl apply -f https://raw.githubusercontent.com/GoogleCloudPlatform/k8s-stackdriver/master/custom-metrics-stackdriver-adapter/deploy/production/adapter.yaml
    
  2. Configure the adapter to use workload identity federation for GKE to get metrics:

    1. Configure the IAM service account:

      gcloud projects add-iam-policy-binding PROJECT_ID \
          --member "serviceAccount:bank-of-anthos@PROJECT_ID.iam.gserviceaccount.com" \
          --role roles/monitoring.viewer
      gcloud iam service-accounts add-iam-policy-binding bank-of-anthos@PROJECT_ID.iam.gserviceaccount.com \
          --role roles/iam.workloadIdentityUser \
          --member "serviceAccount:PROJECT_ID.svc.id.goog[custom-metrics/custom-metrics-stackdriver-adapter]"
      
    2. Annotate the Kubernetes service account that the adapter uses:

      kubectl annotate serviceaccount custom-metrics-stackdriver-adapter \
          --namespace=custom-metrics \
        iam.gke.io/gcp-service-account=bank-of-anthos@PROJECT_ID.iam.gserviceaccount.com
      
    3. Restart the adapter Deployment to propagate the changes:

      kubectl rollout restart deployment custom-metrics-stackdriver-adapter \
          --namespace=custom-metrics
      

Configure autoscaling for the database

When you deployed Bank of Anthos and PostgreSQL earlier in this tutorial,, you deployed the database as a StatefulSet with one primary read/write replica to handle all incoming SQL statements. In this section, you configure horizontal Pod autoscaling to add new standby read-only replicas to handle incoming SELECT statements. A good way to reduce the load on each replica is to distribute SELECT statements, which are read operations. The PostgreSQL deployment includes a tool named Pgpool-II that achieves this load balancing and improves the system's throughput.

PostgreSQL exports the SELECT statement metric as a Prometheus metric. You'll use a lightweight metrics exporter named prometheus-to-sd to send these metrics to Cloud Monitoring in a supported format.

  1. Review the HorizontalPodAutoscaler object:

    # Copyright 2022 Google LLC
    #
    # Licensed under the Apache License, Version 2.0 (the "License");
    # you may not use this file except in compliance with the License.
    # You may obtain a copy of the License at
    #
    #      http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS,
    # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    # See the License for the specific language governing permissions and
    # limitations under the License.
    
    ---
    apiVersion: autoscaling/v2
    kind: HorizontalPodAutoscaler
    metadata:
      name: accounts-db-postgresql
    spec:
      behavior:
        scaleUp:
          stabilizationWindowSeconds: 0
          policies:
          - type: Percent
            value: 100
            periodSeconds: 5
          selectPolicy: Max
      scaleTargetRef:
        apiVersion: apps/v1
        kind: StatefulSet
        name: accounts-db-postgresql
      minReplicas: 1
      maxReplicas: 5
      metrics:
      - type: External
        external:
          metric:
            name: custom.googleapis.com|mypgpool|pgpool2_pool_backend_stats_select_cnt
          target:
              type: AverageValue
              averageValue: "15"
    

    This manifest does the following:

    • Sets the maximum number of replicas during a scale-up to 5.
    • Sets the minimum number of during a scale-down to 1.
    • Uses an external metric to make scaling decisions. In this sample, the metric is the number of SELECT statements. A scale-up event occurs if the incoming SELECT statement count surpasses 15.
  2. Apply the manifest to the cluster:

    kubectl apply -f extras/postgres-hpa/hpa/postgresql-hpa.yaml
    

Configure autoscaling for the web interface

In Deploy Bank of Anthos and PostgreSQL, you deployed the Bank of Anthos web interface. When the number of users increases, the userservice Service consumes more CPU resources. In this section, you configure horizontal Pod autoscaling for the userservice Deployment when the existing Pods use more than 60% of their requested CPU, and for the frontend Deployment when the number of incoming HTTP requests to the load balancer is more than 5 per second.

Configure autoscaling for the userservice Deployment

  1. Review the HorizontalPodAutoscaler manifest for the userservice Deployment:

    # Copyright 2022 Google LLC
    #
    # Licensed under the Apache License, Version 2.0 (the "License");
    # you may not use this file except in compliance with the License.
    # You may obtain a copy of the License at
    #
    #      http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS,
    # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    # See the License for the specific language governing permissions and
    # limitations under the License.
    
    ---
    apiVersion: autoscaling/v2
    kind: HorizontalPodAutoscaler
    metadata:
      name: userservice
    spec:
      behavior:
        scaleUp:
          stabilizationWindowSeconds: 0
          policies:
            - type: Percent
              value: 100
              periodSeconds: 5
          selectPolicy: Max
      scaleTargetRef:
        apiVersion: apps/v1
        kind: Deployment
        name: userservice
      minReplicas: 5
      maxReplicas: 50
      metrics:
        - type: Resource
          resource:
            name: cpu
            target:
              type: Utilization
              averageUtilization: 60
    

    This manifest does the following:

    • Sets the maximum number of replicas during a scale-up to 50.
    • Sets the minimum number of during a scale-down to 5.
    • Uses a built-in Kubernetes metric to make scaling decisions. In this sample, the metric is CPU utilization, and the target utilization is 60%, which avoids both over- and under-utilization.
  2. Apply the manifest to the cluster:

    kubectl apply -f extras/postgres-hpa/hpa/userservice.yaml
    

Configure autoscaling for the frontend deployment

  1. Review the HorizontalPodAutoscaler manifest for the userservice Deployment:

    # Copyright 2022 Google LLC
    #
    # Licensed under the Apache License, Version 2.0 (the "License");
    # you may not use this file except in compliance with the License.
    # You may obtain a copy of the License at
    #
    #      http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS,
    # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    # See the License for the specific language governing permissions and
    # limitations under the License.
    
    ---
    apiVersion: autoscaling/v2
    kind: HorizontalPodAutoscaler
    metadata:
      name: frontend
    spec:
      behavior:
        scaleUp:
          stabilizationWindowSeconds: 0
          policies:
            - type: Percent
              value: 100
              periodSeconds: 5
          selectPolicy: Max
      scaleTargetRef:
        apiVersion: apps/v1
        kind: Deployment
        name: frontend
      minReplicas: 5
      maxReplicas: 25
      metrics:
        - type: External
          external:
            metric:
              name: loadbalancing.googleapis.com|https|request_count
              selector:
                matchLabels:
                  resource.labels.forwarding_rule_name: FORWARDING_RULE_NAME
            target:
              type: AverageValue
              averageValue: "5"
    

    This manifest uses the following fields:

    • spec.scaleTargetRef: The Kubernetes resource to scale.
    • spec.minReplicas: The minimum number of replicas, which is 5 in this sample.
    • spec.maxReplicas: The maximum number of replicas, which is 25 in this sample.
    • spec.metrics.*: The metric to use. In this sample, this is the number of HTTP requests per second, which is a custom metric from Cloud Monitoring provided by the adapter that you deployed.
    • spec.metrics.external.metric.selector.matchLabels: The specific resource label to filter when autoscaling.
  2. Find the name of the forwarding rule from the load balancer to the frontend Deployment:

    export FW_RULE=$(kubectl get ingress frontend -o=jsonpath='{.metadata.annotations.ingress\.kubernetes\.io/forwarding-rule}')
    echo $FW_RULE
    

    The output is similar to the following:

    k8s2-fr-j76hrtv4-default-frontend-wvvf7381
    
  3. Add your forwarding rule to the manifest:

    sed -i "s/FORWARDING_RULE_NAME/$FW_RULE/g" "extras/postgres-hpa/hpa/frontend.yaml"
    

    This command replaces FORWARDING_RULE_NAME with your saved forwarding rule.

  4. Apply the manifest to the cluster:

    kubectl apply -f extras/postgres-hpa/hpa/frontend.yaml
    

Checkpoint: Validate autoscaling setup

Get the state of your HorizontalPodAutoscaler resources:

kubectl get hpa

The output is similar to the following:

NAME                     REFERENCE                            TARGETS             MINPODS   MAXPODS   REPLICAS   AGE
accounts-db-postgresql   StatefulSet/accounts-db-postgresql   10905m/15 (avg)     1         5         2          5m2s
contacts                 Deployment/contacts                  1%/70%              1         5         1          11m
frontend                 Deployment/frontend                  <unknown>/5 (avg)   5         25        1          34s
userservice              Deployment/userservice               0%/60%              5         50        5          4m56s

At this point, you've set up your application and configured autoscaling. Your frontend and database can now scale based on the metrics that you provided.

Simulate load and observe GKE scaling

Bank of Anthos includes a loadgenerator Service that lets you simulate traffic to test your application scaling under load. In this section, you'll deploy the loadgenerator Service, generate a load, and observe the resulting scaling.

Deploy the load testing generator

  1. Create an environment variable with the IP address of the Bank of Anthos load balancer:

    export LB_IP=$(kubectl get ingress frontend -o=jsonpath='{.status.loadBalancer.ingress[0].ip}')
    echo $LB_IP
    

    The output is similar to the following:

    203.0.113.9
    
  2. Add the IP address of the load balancer to the manifest:

    sed -i "s/FRONTEND_IP_ADDRESS/$LB_IP/g" "extras/postgres-hpa/loadgenerator.yaml"
    
  3. Apply the manifest to the cluster:

    kubectl apply -f  extras/postgres-hpa/loadgenerator.yaml
    

The load generator begins adding one user every second, up to 250 users.

Simulate load

In this section, you use a load generator to simulate spikes in traffic and observe your replica count and node count scale up to accommodate the increased load over time. You then end the test and observe the replica and node count scale down in response.

  1. Expose the load generator web interface locally:

    kubectl port-forward svc/loadgenerator 8080
    

    If you see an error message, try again when the Pod is running.

  2. In a browser, open the load generator web interface.

    • If you're using a local shell, open a browser and go to http://127.0.0.1:8080.
    • If you're using Cloud Shell, click Web preview, and then click Preview on port 8080.
  3. Click the Charts tab to observe performance over time.

  4. Open a new terminal window and watch the replica count of your horizontal Pod autoscalers:

    kubectl get hpa -w
    

    The number of replicas increases as the load increases. The scaleup might take approximately ten minutes.

    NAME                     REFERENCE                            TARGETS          MINPODS   MAXPODS   REPLICAS
    accounts-db-postgresql   StatefulSet/accounts-db-postgresql   8326m/15 (avg)   1         5         5
    contacts                 Deployment/contacts                  51%/70%          1         5         2
    frontend                 Deployment/frontend                  5200m/5 (avg)    5         25        13
    userservice              Deployment/userservice               71%/60%          5         50        17
    
  5. Open another terminal window and check the number of nodes in the cluster:

    gcloud container clusters list \
        --filter='name=bank-of-anthos' \
        --format='table(name, currentMasterVersion, currentNodeVersion, currentNodeCount)' \
        --region="us-central1"
    
  6. The number of nodes increased from the starting quantity of three nodes to accommodate the new replicas.

  7. Open the load generator interface and click Stop to end the test.

  8. Check the replica count and node count again and observe as the numbers reduce with the reduced load. The scale down might take some time, because the default stabilization window for replicas in the Kubernetes HorizontalPodAutoscaler resource is five minutes. For more information, refer to Stabilization window.

Clean up

To avoid incurring charges to your Google Cloud account for the resources used in this tutorial, either delete the project that contains the resources, or keep the project and delete the individual resources.

Delete individual resources

Google Cloud creates resources, such as load balancers, based on the Kubernetes objects that you create. To delete all the resources in this tutorial, do the following:

  1. Delete the sample Kubernetes resources:

    kubectl delete \
        -f extras/postgres-hpa/loadgenerator.yaml \
        -f extras/postgres-hpa/hpa \
        -f extras/postgres-hpa/kubernetes-manifests \
        -f extras/jwt/jwt-secret.yaml \
        -f https://raw.githubusercontent.com/GoogleCloudPlatform/k8s-stackdriver/master/custom-metrics-stackdriver-adapter/deploy/production/adapter.yaml
    
  2. Delete the PostgreSQL database:

    helm uninstall accounts-db
    kubectl delete pvc -l "app.kubernetes.io/instance=accounts-db"
    kubectl delete configmaps initdb
    
  3. Delete the GKE cluster and the IAM service account:

    gcloud iam service-accounts delete "bank-of-anthos@PROJECT_ID.iam.gserviceaccount.com" --quiet
    gcloud container clusters delete "bank-of-anthos" --region="us-central1" --quiet
    

Delete the project

    Delete a Google Cloud project:

    gcloud projects delete PROJECT_ID

What's next