Warning

This version of ScalarDB is no longer supported. For details, see the Release Support Policy.

Make ScalarDB or ScalarDL deployed in a Kubernetes cluster environment available from applications

This document explains how to make ScalarDB or ScalarDL deployed in a Kubernetes cluster environment available from applications. To make ScalarDB or ScalarDL available from applications, you can use Scalar Envoy via a Kubernetes service resource named <HELM_RELEASE_NAME>-envoy. You can use <HELM_RELEASE_NAME>-envoy in several ways, such as:

  • Directly from inside the same Kubernetes cluster as ScalarDB or ScalarDL.
  • Via a load balancer from outside the Kubernetes cluster.
  • From a bastion server by using the kubectl port-forward command (for testing purposes only).

The resource name <HELM_RELEASE_NAME>-envoy is decided based on the helm release name. You can see the helm release name by running the helm list command.

$ helm list -n ns-scalar
NAME                    NAMESPACE       REVISION        UPDATED                                 STATUS                                                       CHART                    APP VERSION
scalardb                ns-scalar       1               2023-02-09 19:31:40.527130674 +0900 JST deployed                                                     scalardb-2.5.0           3.8.0
scalardl-auditor        ns-scalar       1               2023-02-09 19:32:03.008986045 +0900 JST deployed                                                     scalardl-audit-2.5.1     3.7.1
scalardl-ledger         ns-scalar       1               2023-02-09 19:31:53.459548418 +0900 JST deployed                                                     scalardl-4.5.1           3.7.1

You can also see the envoy service name <HELM_RELEASE_NAME>-envoy by running the kubectl get service command.

$ kubectl get service -n ns-scalar
NAME                             TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)                           AGE
scalardb-envoy                   LoadBalancer   10.99.245.143    <pending>     60051:31110/TCP                   2m2s
scalardb-envoy-metrics           ClusterIP      10.104.56.87     <none>        9001/TCP                          2m2s
scalardb-headless                ClusterIP      None             <none>        60051/TCP                         2m2s
scalardb-metrics                 ClusterIP      10.111.213.194   <none>        8080/TCP                          2m2s
scalardl-auditor-envoy           LoadBalancer   10.111.141.43    <pending>     40051:31553/TCP,40052:31171/TCP   99s
scalardl-auditor-envoy-metrics   ClusterIP      10.104.245.188   <none>        9001/TCP                          99s
scalardl-auditor-headless        ClusterIP      None             <none>        40051/TCP,40053/TCP,40052/TCP     99s
scalardl-auditor-metrics         ClusterIP      10.105.119.158   <none>        8080/TCP                          99s
scalardl-ledger-envoy            LoadBalancer   10.96.239.167    <pending>     50051:32714/TCP,50052:30857/TCP   109s
scalardl-ledger-envoy-metrics    ClusterIP      10.97.204.18     <none>        9001/TCP                          109s
scalardl-ledger-headless         ClusterIP      None             <none>        50051/TCP,50053/TCP,50052/TCP     109s
scalardl-ledger-metrics          ClusterIP      10.104.216.189   <none>        8080/TCP                          109s

Run application (client) requests to ScalarDB or ScalarDL via service resources directly from inside the same Kubernetes cluster

If you deploy your application (client) in the same Kubernetes cluster as ScalarDB or ScalarDL (for example, if you deploy your application [client] on another node group or pool in the same Kubernetes cluster), the application can access ScalarDB or ScalarDL by using Kubernetes service resources. The format of the service resource name (FQDN) is <HELM_RELEASE_NAME>-envoy.<NAMESPACE>.svc.cluster.local.

The following are examples of ScalarDB and ScalarDL deployments on the ns-scalar namespace:

  • ScalarDB Server

      scalardb-envoy.ns-scalar.svc.cluster.local
    
  • ScalarDL Ledger

      scalardl-ledger-envoy.ns-scalar.svc.cluster.local
    
  • ScalarDL Auditor

      scalardl-auditor-envoy.ns-scalar.svc.cluster.local
    

When using the Kubernetes service resource, you must set the above FQDN in the properties file for the application (client) as follows:

  • Client properties file for ScalarDB Server

      scalar.db.contact_points=<HELM_RELEASE_NAME>-envoy.<NAMESPACE>.svc.cluster.local
      scalar.db.contact_port=60051
      scalar.db.storage=grpc
      scalar.db.transaction_manager=grpc
    
  • Client properties file for ScalarDL Ledger

      scalar.dl.client.server.host=<HELM_RELEASE_NAME>-envoy.<NAMESPACE>.svc.cluster.local
      scalar.dl.ledger.server.port=50051
      scalar.dl.ledger.server.privileged_port=50052
    
  • Client properties file for ScalarDL Ledger with ScalarDL Auditor mode enabled

      # Ledger
      scalar.dl.client.server.host=<HELM_RELEASE_NAME>-envoy.<NAMESPACE>.svc.cluster.local
      scalar.dl.ledger.server.port=50051
      scalar.dl.ledger.server.privileged_port=50052
        
      # Auditor
      scalar.dl.client.auditor.enabled=true
      scalar.dl.client.auditor.host=<HELM_RELEASE_NAME>-envoy.<NAMESPACE>.svc.cluster.local
      scalar.dl.auditor.server.port=40051
      scalar.dl.auditor.server.privileged_port=40052
    

Run application (client) requests to ScalarDB or ScalarDL via load balancers from outside the Kubernetes cluster

If you deploy your application (client) in an environment outside the Kubernetes cluster for ScalarDB or ScalarDL (for example, if you deploy your application [client] on another Kubernetes cluster, container platform, or server), the application can access ScalarDB or ScalarDL by using a load balancer that each cloud service provides.

You can create a load balancer by setting envoy.service.type to LoadBalancer in your custom values file. After configuring the custom values file, you can use Scalar Envoy through a Kubernetes service resource by using the load balancer. You can also set the load balancer configurations by using annotations.

For more details on how to configure your custom values file, see Service configurations.

When using a load balancer, you must set the FQDN or IP address of the load balancer in the properties file for the application (client) as follows.

  • Client properties file for ScalarDB Server

      scalar.db.contact_points=<LOAD_BALANCER_FQDN_OR_IP_ADDRESS>
      scalar.db.contact_port=60051
      scalar.db.storage=grpc
      scalar.db.transaction_manager=grpc
    
  • Client properties file for ScalarDL Ledger

      scalar.dl.client.server.host=<LOAD_BALANCER_FQDN_OR_IP_ADDRESS>
      scalar.dl.ledger.server.port=50051
      scalar.dl.ledger.server.privileged_port=50052
    
  • Client properties file for ScalarDL Ledger with ScalarDL Auditor mode enabled

      # Ledger
      scalar.dl.client.server.host=<LOAD_BALANCER_FQDN_OR_IP_ADDRESS>
      scalar.dl.ledger.server.port=50051
      scalar.dl.ledger.server.privileged_port=50052
        
      # Auditor
      scalar.dl.client.auditor.enabled=true
      scalar.dl.client.auditor.host=<LOAD_BALANCER_FQDN_OR_IP_ADDRESS>
      scalar.dl.auditor.server.port=40051
      scalar.dl.auditor.server.privileged_port=40052
    

The concrete implementation of the load balancer and access method depend on the Kubernetes cluster. If you are using a managed Kubernetes cluster, see the following official documentation based on your cloud service provider:

You can run client requests to ScalarDB or ScalarDL from a bastion server by running the kubectl port-forward command. If you create a ScalarDL Auditor mode environment, however, you must run two kubectl port-forward commands with different kubeconfig files from one bastion server to access two Kubernetes clusters.

  1. (ScalarDL Auditor mode only) In the bastion server for ScalarDL Ledger, configure an existing kubeconfig file or add a new kubeconfig file to access the Kubernetes cluster for ScalarDL Auditor. For details on how to configure the kubeconfig file of each managed Kubernetes cluster, see Configure kubeconfig.
  2. Configure port forwarding to each service from the bastion server.
    • ScalarDB Server

      kubectl port-forward -n <NAMESPACE> svc/<RELEASE_NAME>-envoy 60051:60051
      
    • ScalarDL Ledger

      kubectl --context <CONTEXT_IN_KUBERNETES_FOR_SCALARDL_LEDGER> port-forward -n <NAMESPACE> svc/<RELEASE_NAME>-envoy 50051:50051
      kubectl --context <CONTEXT_IN_KUBERNETES_FOR_SCALARDL_LEDGER> port-forward -n <NAMESPACE> svc/<RELEASE_NAME>-envoy 50052:50052
      
    • ScalarDL Auditor

      kubectl --context <CONTEXT_IN_KUBERNETES_FOR_SCALARDL_AUDITOR> port-forward -n <NAMESPACE> svc/<RELEASE_NAME>-envoy 40051:40051
      kubectl --context <CONTEXT_IN_KUBERNETES_FOR_SCALARDL_AUDITOR> port-forward -n <NAMESPACE> svc/<RELEASE_NAME>-envoy 40052:40052
      
  3. Configure the properties file to access ScalarDB or ScalarDL via localhost.
    • Client properties file for ScalarDB Server

      scalar.db.contact_points=localhost
      scalar.db.contact_port=60051
      scalar.db.storage=grpc
      scalar.db.transaction_manager=grpc
      
    • Client properties file for ScalarDL Ledger

      scalar.dl.client.server.host=localhost
      scalar.dl.ledger.server.port=50051
      scalar.dl.ledger.server.privileged_port=50052
      
    • Client properties file for ScalarDL Ledger with ScalarDL Auditor mode enabled

      # Ledger
      scalar.dl.client.server.host=localhost
      scalar.dl.ledger.server.port=50051
      scalar.dl.ledger.server.privileged_port=50052
           
      # Auditor
      scalar.dl.client.auditor.enabled=true
      scalar.dl.client.auditor.host=localhost
      scalar.dl.auditor.server.port=40051
      scalar.dl.auditor.server.privileged_port=40052