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Create an OpenSearch Multinode Cluster (Optional)

If you have an extra-large or custom deployment that requires more scale than those referenced in Apstra Flow Scaling Considerations, we recommend that you create an OpenSearch multinode cluster. A multinode cluster is a collection of nodes, that work together as a single unit. A multinode cluster can scale to hundreds of nodes, ensures high availability, and prevents downtime.

Create a Multinode Cluster

To create a multinode OpenSearch cluster, follow these steps:

  1. Configure the node type and associated roles.
    1. From the CLI, run /usr/local/bin/startup.
    2. Select the node type in the TUI (text-based UI).
      You can choose from Data Node, Cluster Manager Node, or Coordinating Node. For descriptions about the different node types, see Multinode Roles and Configurations.
    3. Select Quit.
      When the TUI closes, the node name and node type are automatically set. Open your opensearch.yml file to see the results depending on node type:

      Single node

      		 
      node.roles: ["master", "data", "data_content", "data_hot",
    "data_warm", "data_cold", "data_frozen", "ingest",
    "ml", "remote_cluster_client", "transform"]

      Data node

      		 node.roles: ["data" "ingest"]

      Cluster manager node

      		 node.roles: ["data" "ingest"]

      Coodinating node

      		 node.roles: []
    4. Repeat steps 1 through 3 for each node in your configuration.
  2. Configure the cluster.
    Edit the OpenSearch config file with <sudo vi/etc/opensearch/opensearch.yml> to set the IP address on all nodes in the cluster. For example:
  3. Restart OpenSearch for the changes to take affect.
  4. Run the following command to verify that cluster was successfully created.

    In the results output, the status has three possible values as described in Table 1. In our example, the green signifies that the cluster we created is healthy.

    Table 1: Status Values

    green

    All primary and replica shards are active.

    yellow

    All primary shards are active, but some replica shards are unassigned.

    red

    Some primary shards are not active.
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Multinode Roles and Configurations

Table 2 and Table 3 describe the various roles and configurations you can use when configuring a multinode cluster.

Table 2: Multinode Roles

Type of Role

Description

Data node

The data node stores data and participates in the cluster's indexing and search capabilities. Start with 2+ nodes and add more as data volumes grow.

Cluster manager node

The cluster manager node manages the overall operation of a cluster and keeps track of the cluster state. Use odd numbers (3 or 5) for quorum. Avoid using an even number, which can cause instability.

Coordinating (client) node

The coordinating client node manages search and indexing requests, and helps distribute the load across the cluster. Use 2 to 3 nodes to offload data nodes.
Table 3: Scaling Considerations

Sizing Option

Scaling Recommendations

Extra large or custom sizing options

If you are processing over 1 TB of data, or more than 15,000 FPS, consider a multinode cluster. A multinode cluster is also a good option if high availability of OpenSearch is a priority.

Odd versus even number of nodes

For cluster manager nodes, always maintain an odd number to ensure a quorum. You can configure data, ingest and client nodes based on workload without this restriction.
Minimum node counts

For a production environment, a minimum of 3 nodes is recommended to ensure fault tolerance (3 cluster manager nodes and at least 2 data nodes).