Cluster Mode

Once you have a single server running, you can add more servers to form a distributed cluster. These additional servers, Leaf Servers, can be used to improve performance by placing clusters close to the users, to provide additional capacity within a location or to provide separation between different teams.

Origin Server

Firstly the original server configuration needs to be updated to allow it to become the Origin Server. The shared_token option needs to be added to the configuration, this should be a random string that is shared with the Leaf Servers, the value needs to be kept secret.

Each Origin and Leaf server requires a unique location value, this is used to identify the server in the web interface and the spaces controlled by the server.

knot.yaml

server:
  shared_token: L5Eh3a2bwZJCIsT7xl6NiPXcLz1aBt5T
  location: origin

After making these changes restart the server.

Leaf Server

Configuration

An example configuration file can be generated using the knot scaffold --server command:

knot.yaml

# Server configuration
server:
  # Address and port to listen on
  listen: http://127.0.0.1:3000

  # Address and port to listen on for agents
  listen_agent: 0.0.0.0:3010

  # Address and port for the agents to connect to
  agent_endpoint: "srv+knot-server-agent.service.consul"

  # The wildcard domain to expose the web interface of spaces on
  # wildcard_domain: '*.example.com'

  # Disable Proxy functionality
  disable_proxy: false

  terminal:
    webgl: true

  # Encryption key for protected variables
  # encrypt: VF9hmdXZyzNF3rcP6M0P

  # Optional server location, defaults to the hostname
  # location: myservers

  # Shared secret when using leaf servers with an origin server
  # shared_token: secret

  # Enables leaf servers to work in a restricted mode using API tokens
  # enable_leaf_api_tokens: true

  # The address of the origin server, when given along with shared_token the server will be configured as a leaf server
  # origin_server: https://knot-origin.ecample.com:3000

  # MySQL storage
  mysql:
    enabled: false
    # MySQL host if prefixed with srv+ then SRV+ lookup will be performed
    host: localhost
    port: 3306
    user: root
    password: ""
    database: knot

  # BadgerDB storage
  badgerdb:
    enabled: false
    path: ./badgerdb/

  # Redis storage
  redis:
    enabled: false
    # Redis host if prefixed with srv+ then SRV+ lookup will be performed
    hosts:
      - localhost:6379
    password: ""
    db: 0

  # Memory database (only used for session storage if enabled)
  memorydb:
    enabled: false

  nomad:
    addr: http://127.0.0.1:4646
    token: ""

# Optional nameservers to use for SRV lookups
#resolver:
#  consul:
#    - 192.168.0.4:8600
#  nameservers:
#    - 192.168.0.2:53

log:
  level: info

The following items need to be configured in the knot.yaml file in addition to the base configuration:

shared_token - The shared token that is used to authenticate the Leaf Server with the Origin Server, this must match the Origin Server.
location - The location of the server.
origin_server - The address of the Origin Server.

Standalone Server Restricted Leaf Server