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Cluster-Wide Config

Learn how to configure the Cluster-Wide Config settings to fine tune and control proxy cluster’s behavior with performance enhancing configurations.


In API Connectivity Manager, you can apply cluster policies to API Gateways and Developer Portals to further enhance their configuration to meet your requirements. A proxy cluster is a group of instances configured as API Gateways or Developer Portals. Any cluster policy will apply to all instances in a group.

If a proxy cluster is shared between environments, updating cluster policies will effect all the environments.

See the Learn about Policies topic for an overview of the different policy types and available policies.

About the Policy

Use the Cluster-Wide Config settings to fine tune the worker connections, hash table size, and keepalive settings to speed up data processing and improve the performance of the API proxy for large number of connections. When applied, the settings are applicable to all the instances in a proxy cluster. If the proxy cluster is shared between environments, the changes made in any environment will be reflected in all the other environments.

Intended Audience

This guide is meant for Infrastructure Administrators.

Infrastructure Administrators ensure uniform governance across an organization’s infrastructure by setting policies at the infrastructure level, enabling teams to build APIs without interruption while adhering to the organization’s standards.

Workflow for Applying Policy

To apply the policy or make changes to it, here’s what you need to do:

  • Create an environment or edit an existing one.
  • Check the cluster config settings for the environment to see if the policy has been applied.
  • Edit the policy to make changes for each cluster. Save and publish the changes.

Policy Settings

The following table lists the configurable settings and their default values for the policy.

Field Datatype Possible Values Description Required Default
mapHashBucketSize integer example: 256 Sets the bucket size for the map hash table. No 128
mapHashMaxSize integer example: 2048 Sets the maximum bucket size for the map hash table. No 2048
serverNamesHashBucket integer example: 256 Sets the bucket size for the server names hash tables No 256
serverNamesHashMaxSize integer example: 1024 Sets the maximum size of the server names hash tables. No 1024
workersConfig.connections integer In range 256–65536 Sets the maximum number of simultaneous connections that can be opened by a worker process. No 8192
workersConfig.maxProcesses string ^(auto|[1-9]|[1-2][0-9]|3[0-2])$ Defines the number of worker processes. No auto
workersConfig.maxLimitForOpenFile integer In range 512–262144 Changes the limit on the maximum number of open files (RLIMIT_NOFILE) for worker processes. Used to increase the limit without restarting the main process. No 20000
clientConnection.keepaliveTimeout string ^([0-9]+)(([h|m|s]){1})$ The first parameter sets a timeout during which a keep-alive client connection will stay open on the server side. No 75s
clientConnection.keepaliveHeaderTimeout string ^([0-9]+)(([h|m|s]){1})$ ? No
clientConnection.keepaliveRequests integer In range 50–20000 Sets the maximum number of requests that can be served through one keepalive connection. No 1000
clientConnection.keepaliveTime string ^([0-9]+)(([h|m|s]){1})$ Maximum time during which requests can be processed through one keepalive connection. No “1h”
clientHeaderBuffer.size string ([.\d]+)(?:M|K) Sets the maximum size of buffers used for reading a large client request header. No 8K
clientHeaderBuffer.number integer In range 1–64 Sets the maximum number of buffers used for reading a large client request header. No 4
clientHeaderBuffer.timeout string ^[0-9]+[h|m|s]{1}$ Defines a timeout for reading client request header. No “60s”

Updating Cluster-Wide Policy

See Also:
You can use tools such as curl or Postman to interact with the API Connectivity Manager REST API. The API URL follows the format https://<NMS_FQDN>/api/acm/<API_VERSION> and must include authentication information with each call. For more information about authentication options, please refer to the API Overview.

To create an Cluster-Wide Config settings using the REST API, send an HTTP PUT request to the Add-Endpoint-Name-Here endpoint.

Method Endpoint
PUT /infrastructure/workspaces/{infraWorkspaceName}/proxy-clusters/{clusterName}
JSON request - Cluster-Wide Config with minimum configuration
    "policies": {
      "cluster-wide-config": [],
JSON request - Cluster-Wide Config with all options specified
  "policies": {
    "cluster-wide-config": [
        "action": {
            "clientConnection": {
                "keepaliveRequests": 1000,
                "keepaliveTime": "1h",
                "keepaliveTimeout": "75s"
            "clientHeaderBuffer": {
                "number": 4,
                "size": "8K",
                "timeout": "60s"
            "mapHashBucketSize": 128,
            "mapHashMaxSize": 2048,
            "serverNamesHashBucket": 256,
            "serverNamesHashMaxSize": 1024,
            "workersConfig": {
                "connections": 8192,
                "maxLimitForOpenFile": 20000,
                "maxProcesses": "auto"

To create a Cluster-Wide Config setting using the web interface:

  1. In a web browser, go to the FQDN for your NGINX Management Suite host and log in. Then, from the Launchpad menu, select API Connectivity Manager.
  2. On the left menu, select Infrastructure.
  3. Choose the workspace that contains your cluster’s environment from the list of workspaces.
  4. In the Environments section, select the environment name for your cluster.
  5. In the list of clusters, locate the cluster you want to add the policy to. On the Actions menu (represented by an ellipsis, ...), select Edit Cluster Config.
  6. On the left menu, select Cluster Policies.
  7. In the list of Cluster Policies, the Cluster-Wide Config setting should be enabled by default. To edit the policy, select the ellipsis icon (...), then select Edit Cluster Config.
  8. Customize the policy settings to suit your requirements. Refer to the Policy Settings section for an overview of the available options and their possible configurations.
  9. Select Save to save the changes.
  10. Select Save and Submit to publish the policy changes to the environment.

Verify the Policy

Confirm that the policy has been set up and configured correctly by taking these steps:

  • Verify the NGINX configuration was applied by this policy.