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Deploy a High Available Cache Cluster on Local Storage

Previously, we covered how to deploy a single node EloqKV cluster using eloqctl. In this document, we will focus on deploying a highly available cache cluster on local storage (RocksDB).

1. Prerequisites​

Please ensure you've reviewed the following document:

2. Deploy Eloqctl on the control machine​

For step-by-step guidance, please check out the previous document:

3. Enable Persistent Data Store for Durability​

Template EloqKV configuration file EloqKv.ini can be found in the .eloqctl/config/ directory.

To deploy a highly available cache cluster on local storage, you need to first enable persistent data dtore feature in EloqKv.ini.

# set it to `on` to turn on persistent storage
enable_data_store=on

4. Initialize the cluster topology file​

Example cluster topology files can be found in the .eloqctl/config/examples/ directory.

To deploy a highly available cluster, use eloqkv_rocksdb_standby_with_voter.yaml as the default configuration template.

# example yaml file
.eloqctl/config/examples/eloqkv_rocksdb_standby_with_voter.yaml

To enable high availability, edit the eloqkv_rocksdb_standby_with_voter.yaml file. Setup primary, standby and voter nodes among different machines.

connection:
  username: "${USER}"
  auth_type: "keypair"
  auth:
    keypair: "/home/${USER}/.ssh/id_rsa"
deployment:
  cluster_name: "eloqkv_with_hot_standby_and_voter"
  product: "EloqKV"
  version: "latest"
  install_dir: "/home/${USER}"
  tx_service:
    tx_host_ports: [10.0.0.1:6379]
    standby_host_ports: [10.0.0.2:6379]
    voter_host_ports: [10.0.0.3:6379]

  storage_service:
    rocksdb: Local

For detailed explanations for each configuration option in the YAML file, please refer to the previous document Deploy Single Node Cluster. In this document, we will focus specifically on the high availability aspects of the configuration file.

  • tx_service.tx_host_ports:
    Type: List of Strings
    List of primary nodes. Each primary node handles both read and write operations, continuously replicating new changes to the standby nodes.

  • tx_service.standby_host_ports:
    Type: List of Strings
    List of hot standby nodes. Each standby node handles read operations and automatically takes over as the primary node in case of a primary node failure.

  • tx_service.voter_host_ports:
    Type: Integer
    List of voter nodes. In the event of a primary node failure, voters participate in electing a new primary node. Voter nodes do not store any data and are not eligible for election as the primary node.

  • storage_service.rocksdb:
    Type: String
    Local indicates that an embedded RocksDB engine is used for on-disk data storage.

5. Run the deployment command​

After you modified the eloqkv_rocksdb_standby_with_voter.yaml. Use the eloqctl launch command to provision an EloqKV cluster

eloqctl launch ${HOME}/.eloqctl/config/examples/eloqkv_rocksdb_standby_with_voter.yaml

The command will installed the EloqKV componnets in the specified cluster.

If you see the following message, the EloqKV cluster has been successfully provisioned:

Launch cluster finished, Enjoy!

Feel free to use eloqkv-cli or any other Redis client to connect to EloqKV and enjoy exploring its features.