ClusterManager Settings - Storm Streaming Server

The ClusterManager is the central coordination module of a Storm Streaming Server cluster. It tracks all active streams, coordinates distributed transcoding, and handles authentication between cluster nodes. Every origin, transcode, and edge application in the cluster connects to at least one ClusterManager instance.

Sample Configuration

The ClusterManager is configured within the <ClusterManager> block of the config/preferences.xml file. This is a server-level setting, not an application-level one.

config/preferences.xml - ClusterManager configuration

xml

<ClusterManager enabled="true">
    <Identity>ClusterManager01</Identity>
    <GlobalStatistics>true</GlobalStatistics>
    <Authentication>
        <IPWhiteList>192.168.10.2, 192.168.10.3, 192.168.10.4</IPWhiteList>
        <Secret>MySecretKey123!</Secret>
    </Authentication>
    <ClusterTranscoding enabled="true" active="true">
        <MinimalSourceResolution>1280x720</MinimalSourceResolution>
        <StreamGraceTimeout>300</StreamGraceTimeout>
        <StreamEvaluationInterval>30</StreamEvaluationInterval>
        <AliasMode>false</AliasMode>
        <StreamWeightOverrides enabled="false" />
    </ClusterTranscoding>
    <AWSModule enabled="false">
        <AccessKeyID>AKIAIOSFODNN7EXAMPLE</AccessKeyID>
        <SecretAccessKey>wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY</SecretAccessKey>
        <Regions>
            <Region>us-east-1</Region>
            <Region>eu-west-1</Region>
        </Regions>
    </AWSModule>
</ClusterManager>

General Settings

Parameter	Description	Required
`enabled`	Enables or disables the ClusterManager module. Attribute on the `<ClusterManager>` element.	Yes
`<Identity>`	A unique identifier for this ClusterManager instance (minimum 3 characters). Useful for distinguishing between primary and secondary instances in redundant setups (e.g. `Primary`, `Secondary`).	Yes
`<GlobalStatistics>`	If set to `true`, the ClusterManager collects and aggregates statistics from all connected nodes.	No

Authentication

The <Authentication> block controls how cluster nodes authenticate when connecting to the ClusterManager.

Authentication block

xml

<Authentication>
    <IPWhiteList>192.168.10.2, 192.168.10.3, 192.168.10.4</IPWhiteList>
    <Secret>MySecretKey123!</Secret>
</Authentication>

Parameter	Description	Required
`<IPWhiteList>`	Comma-separated list of IP addresses or CIDR ranges allowed to connect. If empty, all IPs are permitted.	No
`<Secret>`	Shared secret that all applications must present when connecting to this ClusterManager. Minimum 8 characters, must contain at least one special character.	Yes

Security Warning

Leaving the IP whitelist empty is not recommended for production environments. Restrict access to known cluster node IPs whenever possible.

Cluster Transcoding

The <ClusterTranscoding> block configures distributed transcoding — the ClusterManager's ability to dynamically assign and revoke transcoding tasks across transcode nodes based on stream demand.

ClusterTranscoding block

xml

<ClusterTranscoding enabled="true" active="true">
    <MinimalSourceResolution>1280x720</MinimalSourceResolution>
    <StreamGraceTimeout>300</StreamGraceTimeout>
    <StreamEvaluationInterval>30</StreamEvaluationInterval>
    <AliasMode>false</AliasMode>
    <StreamWeightOverrides enabled="false" />
</ClusterTranscoding>

Parameter	Description	Default
`enabled`	Enables or disables distributed transcoding within the cluster.	`false`
`active`	Runtime state of transcoding. Can be toggled via the Control Panel without restarting the server. When `false`, no new transcoding tasks are assigned.	`false`
`<MinimalSourceResolution>`	Minimum source resolution (e.g. `1280x720`) required for a stream to qualify for transcoding. Streams below this resolution are skipped.	—
`<StreamGraceTimeout>`	Grace period in seconds during which a stream, once assigned for transcoding, is protected from having its transcoding revoked.	`300`
`<StreamEvaluationInterval>`	Interval in seconds at which the ClusterManager re-evaluates all streams to determine whether transcoding should be assigned or revoked.	`30`
`<AliasMode>`	If set to `true`, alias-based stream identification is used for transcoding decisions.	`false`

The ClusterManager dynamically allocates transcoding based on demand. Each transcode node has a defined maximum number of concurrent tasks. When capacity is limited, the ClusterManager prioritizes streams with the highest number of viewers (or based on the weight system, if enabled).

Stream Weight Overrides

By default, the ClusterManager uses the number of viewers to prioritize which streams should be transcoded. The <StreamWeightOverrides> system allows you to override this behavior by fetching custom weights from an external API.

StreamWeightOverrides block

xml

<StreamWeightOverrides enabled="true">
    <WeightTimeout>3600</WeightTimeout>
    <RequestURL>https://api.example.com/weights/{streamKey}</RequestURL>
    <XApiKey>your-api-key</XApiKey>
</StreamWeightOverrides>

Parameter	Description	Default
`enabled`	Enables weight-based transcoding prioritization via an external API.	`false`
`<WeightTimeout>`	Cache timeout in seconds — how long a fetched weight is valid before the ClusterManager requests fresh data.	—
`<RequestURL>`	API endpoint for weight queries. Use `{streamKey}` as a placeholder for the stream key.	—
`<XApiKey>`	API key sent as `X-Api-Key` header with each request.	—

The {streamKey} placeholder in the URL is replaced with the actual stream key at request time.

Expected JSON response:

Weight API response

json

{
  "weight": 10,
  "weightStrategy": "value"
}

Available weight strategies:

Strategy	Description
`add`	Adds the number of viewers to the provided weight.
`multiply`	Multiplies the number of viewers by the provided weight.
`set`	Uses the provided weight directly, ignoring the viewer count.
`value`	Uses the number of viewers as the weight (default behavior).

AWS Module

The <AWSModule> block enables integration with Amazon Web Services for cloud-based cluster deployments.

AWSModule block

xml

<AWSModule enabled="true">
    <AccessKeyID>AKIAIOSFODNN7EXAMPLE</AccessKeyID>
    <SecretAccessKey>wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY</SecretAccessKey>
    <Regions>
        <Region>us-east-1</Region>
        <Region>eu-west-1</Region>
    </Regions>
</AWSModule>

Parameter	Description	Required
`enabled`	Enables or disables AWS integration.	Yes
`<AccessKeyID>`	AWS IAM access key ID.	Yes
`<SecretAccessKey>`	AWS IAM secret access key.	Yes
`<Regions>`	List of AWS regions where cluster resources can be deployed.	Yes

Security Tip

Use environment variables for AWS credentials to keep them out of configuration files: <AccessKeyID>${EV:AWS_ACCESS_KEY_ID}</AccessKeyID>.

Environment Variables

All parameters (except enabled and active attributes) support environment variables using the ${EV:VARIABLE_NAME} syntax. This is particularly recommended for sensitive values like the cluster secret and AWS credentials.

Environment variable examples

xml

<Authentication>
    <Secret>${EV:CLUSTER_SECRET}</Secret>
</Authentication>

Note

Fields locked by environment variables cannot be modified via the REST API.

Support Needed?

If you have any questions or need assistance, please create a support ticket and our team will help you.