Start ArangoDB Cluster to Cluster Synchronization on Kubernetes

This tutorial guides you through the steps needed to configure an ArangoDB datacenter to datacenter replication between two ArangoDB clusters running in Kubernetes.

Requirements

1. This tutorial assumes that you have 2 ArangoDB clusters running in 2 different Kubernetes clusters.
2. Both Kubernetes clusters are equipped with support for Services of type LoadBalancer.
3. You can create (global) DNS names for configured Services with low propagation times. E.g. use Cloudflare.
4. You have 4 DNS names available:
   • One for the database in the source ArangoDB cluster. E.g. src-db.mycompany.com
   • One for the ArangoDB syncmasters in the source ArangoDB cluster. E.g. src-sync.mycompany.com
   • One for the database in the destination ArangoDB cluster. E.g. dst-db.mycompany.com
   • One for the ArangoDB syncmasters in the destination ArangoDB cluster. E.g. dst-sync.mycompany.com

Step 1: Enable Datacenter Replication Support on source ArangoDB cluster

Set your current Kubernetes context to the Kubernetes source cluster.

Edit the ArangoDeployment of the source ArangoDB clusters.

Set:

• spec.tls.altNames to ["src-db.mycompany.com"] (can include more names / IP addresses)
• spec.sync.enabled to true
• spec.sync.externalAccess.masterEndpoint to ["https://src-sync.mycompany.com:8629"]
• spec.sync.externalAccess.accessPackageSecretNames to ["src-accesspackage"]

Step 2: Extract access-package from source ArangoDB cluster

Run:

kubectl get secret src-accesspackage --template='{{index .data "accessPackage.yaml"}}' | \
  base64 -D > accessPackage.yaml

Step 3: Configure source DNS names

Run:

kubectl get service

Find the IP address contained in the LoadBalancer column for the following Services:

• <deployment-name>-ea Use this IP address for the src-db.mycompany.com DNS name.
• <deployment-name>-sync Use this IP address for the src-sync.mycompany.com DNS name.

The process for configuring DNS names is specific to each DNS provider.

Step 4: Enable Datacenter Replication Support on destination ArangoDB cluster

Set your current Kubernetes context to the Kubernetes destination cluster.

Edit the ArangoDeployment of the source ArangoDB clusters.

Set:

• spec.tls.altNames to ["dst-db.mycompany.com"] (can include more names / IP addresses)
• spec.sync.enabled to true
• spec.sync.externalAccess.masterEndpoint to ["https://dst-sync.mycompany.com:8629"]

Step 5: Import access package in destination cluster

Run:

kubectl apply -f accessPackage.yaml

Note: This imports two Secrets, containing TLS information about the source cluster, into the destination cluster

Step 6: Configure destination DNS names

Run:

kubectl get service

Find the IP address contained in the LoadBalancer column for the following Services:

• <deployment-name>-ea Use this IP address for the dst-db.mycompany.com DNS name.
• <deployment-name>-sync Use this IP address for the dst-sync.mycompany.com DNS name.

The process for configuring DNS names is specific to each DNS provider.

Step 7: Create an ArangoDeploymentReplication resource

Create a yaml file (e.g. called src-to-dst-repl.yaml) with the following content:

apiVersion: "replication.database.arangodb.com/v1alpha"
kind: "ArangoDeploymentReplication"
metadata:
  name: "replication-src-to-dst"
spec:
  source:
    masterEndpoint: ["https://src-sync.mycompany.com:8629"]
    auth:
      keyfileSecretName: src-accesspackage-auth
    tls:
      caSecretName: src-accesspackage-ca
  destination:
    deploymentName: <dst-deployment-name>

Step 8: Wait for DNS names to propagate

Wait until the DNS names configured in step 3 and 6 resolve to their configured IP addresses.

Depending on your DNS provides this can take a few minutes up to 24 hours.

Step 9: Activate replication

Run:

kubectl apply -f src-to-dst-repl.yaml

Replication from the source cluster to the destination cluster will now be configured.

Check the status of the replication by inspecting the status of the ArangoDeploymentReplication resource using:

kubectl describe ArangoDeploymentReplication replication-src-to-dst

As soon as the replication is configured, the Add collection button in the Collections page of the web UI (of the destination cluster) will be grayed out.