Deploy a High Availability Cluster

Ella Core can be deployed as a high-availability cluster to provide redundancy and failover capabilities. See High Availability for more information.

Prerequisites

• Three hosts meeting the standard system requirements.
• Ella Core installed on each host via the Install guide. Do not start the service yet.
• A reachable TCP port on each host for inter-node traffic (this guide uses 7000).

1. Configure node 1

Put this in core.yaml on node 1. Adjust interface names, addresses, and ports to match the host.

core.yaml (node 1)

logging:
  system:
    level: "info"
    output: "stdout"
  audit:
    output: "stdout"
db:
  path: "/var/snap/ella-core/common/ella.db"
interfaces:
  n2:
    address: "10.0.0.1"
    port: 38412
  n3:
    name: "n3"
  n6:
    name: "eth0"
  api:
    address: "10.0.0.1"
    port: 5002
xdp:
  attach-mode: "native"
cluster:
  enabled: true
  node-id: 1
  bind-address: "10.0.0.1:7000"
  peers:
    - "10.0.0.1:7000"
    - "10.0.0.2:7000"
    - "10.0.0.3:7000"

2. Start node 1

sudo snap start --enable ella-core.cored

3. Create the admin user

Open https://10.0.0.1:5002 in a browser, create the admin, and log in.

4. Add node 2

On node 1, open the Cluster page and click Add Node. Select node ID 2, click Mint Token, then copy the token.

Create core.yaml on node 2 using the same shape as node 1, with bind-address: "10.0.0.2:7000". Paste the copied token block over the placeholder:

core.yaml (node 2, cluster block)

cluster:
  enabled: true
  node-id: 2
  bind-address: "10.0.0.2:7000"
  peers:
    - "10.0.0.1:7000"
    - "10.0.0.2:7000"
    - "10.0.0.3:7000"
  join-token: "ejYM..."

Start node 2:

sudo snap start --enable ella-core.cored

5. Add node 3

Repeat step 4 on node 3.

6. Verify

On the Cluster page, all three nodes appear as Voter, one as Leader, all Healthy.