Configure mongot

Use a YAML configuration file to configure mongot for MongoDB Search and Vector Search deployments. The following example shows the full configuration structure with all available settings:

syncSource:
   replicaSet: <object>
      hostAndPort: <string or list of strings>
      x509: <object>
         caFile: <string>
         tlsCertificateKeyFile: <string>
         tlsCertificateKeyFilePasswordFile: <string>
      scramAuth: <object>
         username: <string>
         passwordFile: <string>
         authSource: <string>
         tls: <object>
            enabled: <boolean>
            caFile: <string>
            tlsCertificateKeyFile: <string>
            tlsCertificateKeyFilePasswordFile: <string>
   router: <object>
      hostAndPort: <string or list of strings>
      x509: <object>
         caFile: <string>
         tlsCertificateKeyFile: <string>
         tlsCertificateKeyFilePasswordFile: <string>
      scramAuth: <object>
         username: <string>
         passwordFile: <string>
         authSource: <string>
         tls: <object>
            enabled: <boolean>
            caFile: <string>
            tlsCertificateKeyFile: <string>
            tlsCertificateKeyFilePasswordFile: <string>
   replicationReader:
      readPreference: <string>
      tagSets: <string or list of strings>
storage: <object>
   dataPath: <string>
server: <object>
   grpc: <object>
      address: <string>
      tls: <object>
         mode: <string>
         certificateKeyFile: <string>
         certificateKeyFilePasswordFile: <string>
         caFile: <string>
   name: <string>
metrics: <object>
   enabled: <boolean>
   address: <string>
healthCheck: <object>
   address: <string>
logging: <object>
   verbosity: <string>
   logPath: <string>
embedding:
   providerEndpoint: <string>
   queryKeyFile: <string>
   indexingKeyFile: <string>
   isAutoEmbeddingViewWriter: <boolean>
advancedConfigs: <object>
   indexing: <object>
      lucene: <object>
         refresh: <object>
            intervalMs: <int>
         mergePolicy: <object>
            tiered: <object>
               vectorMergePolicy: <object>
                  mergeBudgetMb: <int>
         mergeScheduler: <object>
            concurrent: <object>
               maxThreadCount: <int>
         fieldLimit: <int>
   querying: <object>
      lucene: <object>
         maxClauseLimit: <int>
         vectorFloorSegmentMB: <double>
   replication: <object>
      mongodb: <object>
         numConcurrentInitialSyncs: <int>
         numConcurrentChangeStreams: <int>
         numIndexingThreads: <int>
         numConcurrentSynonymSyncs: <int>
   autoEmbedding: <object>
      materializedView: <object>
         numConcurrentChangeStreams: <int>
         numIndexingThreads: <int>
         numEmbeddingThreads: <int>
         numConcurrentInitialSyncs: <int>
         matViewWriterMaxConnections: <int>
         mvWriteRateLimitRps: <int>
         embeddingProviderRpsLimit: <int>
   ftdc: <object>
      enabled: <boolean>
      directorySizeMb: <int>
      fileSizeMb: <int>
      collectionPeriodMillis: <int>

Required Settings

This section describes settings required for all mongot deployments. If you define only the required settings, mongot uses the defaults for all optional settings.

syncSource.replicaSet

Type: Object

Replication connections to mongod for mongot.

syncSource.replicaSet.hostAndPort

Type: String or List of Strings

One or more host and port specifiers used to construct the seed list in the mongod connection string. Regardless of the number of specifiers provided, mongot establishes the connection in replica set mode, not standalone mode.

storage.dataPath

Type: String

Path that mongot must use as a base path for storing index data and the local index catalog.

server

Type: Object

Settings for the mongot query servers.

server.grpc

Type: Object

Listen server settings for gRPC communication between mongot and mongod.

server.grpc.address

Type: String

Address on which the gRPC listen server listens. Use the following format:

<host>:<port>

In self-managed deployments, this address must be reachable by the mongod processes that send search and index management traffic to mongot. Configure it so it matches the host and port that mongod uses for its mongotHost and searchIndexManagementHostAndPort settings.

For single-host development, localhost is the safest default. If mongod and mongot run on different hosts, set server.grpc.address to an interface that mongod can reach.

Warning

Depending on your system topology, it may be necessary to bind the mongot query server to an interface accessible from your MongoDb Cluster. While binding to the 0.0.0.0 IP address is permitted, it exposes the server to all public networks and carries the risk of unauthorized access.

To enhance security, consider restricting server.grpc.address to specific interfaces that are controlled and protected at the network layer such as localhost or other trusted internal addresses.

Optional Settings

This section describes optional and conditionally required settings for mongot. If you omit these settings, mongot uses the specified default value when applicable.

Replica Set Authentication Settings

syncSource.replicaSet.x509

Type: Object

Necessity: Required if you do not use syncSource.replicaSet.scramAuth

X.509 certificate settings for authenticating mongot with mongod.

syncSource.replicaSet.x509.caFile

Type: String

Necessity: Required if you use syncSource.replicaSet.x509

Certificate Authority (CA) file that contains trusted certificates for verifying the certificate presented by mongod. The file must contain an X.509 certificate collection in PEM format.

syncSource.replicaSet.x509.tlsCertificateKeyFile

Type: String

Necessity: Required if you use syncSource.replicaSet.x509

Path to the PEM file that contains the X.509 certificate and private key for authenticating mongot with mongod. Required when you configure syncSource.replicaSet.x509.

syncSource.replicaSet.x509.tlsCertificateKeyFilePasswordFile

Type: String

Necessity: Optional

Path to the file that contains the password to decrypt the certificate key file specified in syncSource.replicaSet.x509.tlsCertificateKeyFile.

syncSource.replicaSet.scramAuth

Type: Object

Necessity: Required if you do not use syncSource.replicaSet.x509

Settings for SCRAM authentication.

syncSource.replicaSet.scramAuth.username

Type: String

Necessity: Required

The username to authenticate with.

syncSource.replicaSet.scramAuth.passwordFile

Type: String

Necessity: Required

Path to a file that contains the password to authenticate with.

syncSource.replicaSet.scramAuth.authSource

Type: String

Necessity: Optional

Default: admin

Name of the database associated with the mongot authentication credentials.

syncSource.replicaSet.scramAuth.tls

Type: Object

Necessity: Optional

Default: false

Settings for TLS.

syncSource.replicaSet.scramAuth.tls.enabled

Type: Boolean

Necessity: Required if you specify syncSource.replicaSet.scramAuth.tls

Flag to enable TLS authentication. Set to true to enable TLS authentication.

syncSource.replicaSet.scramAuth.tls.caFile

Type: String

Necessity: Optional

Certificate Authority (CA) file that contains trusted certificates for verifying the certificate presented by mongod. The file must contain an X.509 certificate collection in PEM format.

syncSource.replicaSet.scramAuth.tls.tlsCertificateKeyFile

Type: String

Necessity: Optional

Path to the PEM file that contains the X.509 certificate and private key for authenticating mongot with mongod.

syncSource.replicaSet.scramAuth.tls.tlsCertificateKeyFilePasswordFile

Type: String

Necessity: Optional

Path to the file that contains the password to decrypt the certificate key file specified in syncSource.replicaSet.scramAuth.tls.tlsCertificateKeyFile.

Sharded Clusters Settings

syncSource.router

Type: Object

Replication connections to mongos for mongot. If omitted, mongot assumes it is running in a non-sharded environment. Required for sharded cluster deployments.

syncSource.router.x509

Type: Object

Necessity: Required if you do not use syncSource.router.scramAuth

X.509 certificate settings for authenticating mongot with mongos.

syncSource.router.x509.caFile

Type: String

Necessity: Required if you use syncSource.router.x509

Certificate Authority (CA) file that contains trusted certificates for verifying the certificate presented by mongos. The file must contain an X.509 certificate collection in PEM format.

syncSource.router.x509.tlsCertificateKeyFile

Type: String

Necessity: Required if you use syncSource.router.x509

Path to the PEM file that contains the X.509 certificate and private key for authenticating mongot with mongos. Required when you configure syncSource.router.x509.

syncSource.router.x509.tlsCertificateKeyFilePasswordFile

Type: String

Necessity: Optional

Path to the file that contains the password to decrypt the certificate key file specified in syncSource.router.x509.tlsCertificateKeyFile.

syncSource.router.scramAuth

Type: Object

Necessity: Required if you do not use syncSource.router.x509

Settings for SCRAM authentication.

syncSource.router.scramAuth.username

Type: String

Necessity: Required

The username to authenticate with.

syncSource.router.scramAuth.passwordFile

Type: String

Necessity: Required

Path to a file that contains the password to authenticate with.

syncSource.router.scramAuth.authSource

Type: String

Necessity: Optional

Name of the database associated with the mongot authentication credentials. If unspecified, authSource defaults to admin.

syncSource.router.scramAuth.tls

Type: Object

Necessity: Optional

Default: false

Settings for TLS.

syncSource.router.scramAuth.tls.enabled

Type: Boolean

Necessity: Required if you specify syncSource.router.scramAuth.tls

Flag to enable TLS authentication. Set to true to enable TLS authentication.

syncSource.router.scramAuth.tls.caFile

Type: String

Necessity: Optional

Certificate Authority (CA) file that contains trusted certificates for verifying the certificate presented by mongos. The file must contain an X.509 certificate collection in PEM format.

syncSource.router.scramAuth.tls.tlsCertificateKeyFile

Type: String

Necessity: Optional.

Path to the PEM file that contains the X.509 certificate and private key for authenticating mongot with mongos.

syncSource.router.scramAuth.tls.tlsCertificateKeyFilePasswordFile

Type: String

Path to the file that contains the password to decrypt the certificate key file specified in syncSource.router.scramAuth.tls.tlsCertificateKeyFile.

Replication Read Preference Settings

syncSource.replicationReader

Type: Object

Controls the read preference that mongot uses when reading from the replica set for replication.

To filter reads by replica set member tags, specify syncSource.replicationReader.tagSets.

syncSource.replicationReader.readPreference

Type: String

Default: secondaryPreferred

Read preference mongot uses for replication operations. You can specify the following values:

primary
primaryPreferred
secondary
secondaryPreferred
nearest

Note

Index management commands always use primary read preference, regardless of this setting.

syncSource.replicationReader.tagSets

Type: Array

Array of tag sets that filter which replica set members receive replication reads. You cannot configure this setting if syncSource.replicationReader.readPreference is primary.

Each element of tagSets is an array of { name: <name>, value: <value> } objects that match replica set member tags. mongot evaluates tag sets in order and uses the first tag set that matches a member. For example:

tagSets:
  - [ { name: hostname, value: mongod1 },
      { name: region, value: us-east-1 } ]

gRPC Server Settings

The server.grpc.address setting is required. All other server.grpc settings are optional.

server.grpc.tls

Type: Object

TLS configuration options for the gRPC listen server.

server.grpc.tls.mode

Type: String

TLS mode for the gRPC server. Must be one of the following values:

"TLS"
"mTLS"
"disabled"

Required when you configure server.grpc.tls.

server.grpc.tls.certificateKeyFile

Type: String

PEM file that contains a valid X.509 certificate for mongot using a PKCS#8 private key. mongod validates this certificate using a Certificate Authority (CA) file that you specify with the --tlsCAFile option. Required when server.grpc.tls.mode is "TLS" or "mTLS".

server.grpc.tls.certificateKeyFilePasswordFile

Type: String

Path to the file that contains the password to decrypt the certificate key file specified in server.grpc.tls.certificateKeyFile.

server.grpc.tls.caFile

Type: String

Certificate Authority (CA) file that contains trusted certificates for verifying the certificate presented by mongod. The file must contain an X.509 certificate collection in PEM format. Required when server.grpc.tls.mode is "mTLS".

server.name

Type: String

User-provided name to identify a mongot instance. MongoDB uses server.name to identify mongot hosts across programmatic interfaces such as $listSearchIndexes. If you omit this setting, MongoDB generates a name automatically.

Metrics Settings

metrics

Type: Object

Settings for the mongot Prometheus metrics endpoint listener.

metrics.enabled

Type: Boolean

Flag that enables the Prometheus metrics endpoint. If you set this to false, MongoDB parses and validates the syntax of the other settings in the metrics block but does not start the Prometheus metrics listener. Required when you configure metrics.

metrics.address

Type: String

Default: localhost:9946

Socket address (IPv4 or IPv6) on which the Prometheus /metrics endpoint is exposed. Use the following format:

<host>:<port>

Health Checks Settings

healthCheck

Type: Object

Settings for the mongot health check endpoint. You cannot disable the health check endpoint, but you can configure its listen address.

healthCheck.address

Type: String

Default: localhost:8080

Address on which the health check listener listens. Use the following format:

<host>:<port>

Logging Settings

logging

Type: Object

Options for logging.

logging.verbosity

Type: String

Default: INFO

Verbosity of logging. The value must be a valid Logback log level.

logging.logPath

Type: String

Path to a file where mongot writes logs using a Logback file appender. If you omit this setting, MongoDB does not create or configure a log file appender.

Automated Embedding Settings

Basic Settings

Configure the following settings to enable Automated Embedding.

Note

queryKeyFile and indexingKeyFile work as a pair. If you do not configure either file, mongot logs a warning and disables auto-embedding.
providerEndpoint is optional. When set, mongot applies it as an override for the configured embedding service endpoint.
isAutoEmbeddingViewWriter defaults to false if you omit it.

embedding.providerEndpoint

Type: String

URL of the embedding provider endpoint. Optional override for the default embedding provider endpoint. Use this if you want mongot to send embedding requests to a specific provider endpoint instead of the default endpoint.

embedding.queryKeyFile

Type: String

Path to the file that contains the key for the query-time embedding requests. Required for Automated Embedding.

embedding.indexingKeyFile

Type: String

Path to the file that contains the key for the index-time embedding requests. Required for Automated Embedding.

embedding.isAutoEmbeddingViewWriter

Type: Boolean

Flag to designate the leader mongot instance responsible for writing the automated embedding View. If true, this mongot instance acts as the writer for auto-embedding materialized-view updates.

For single-instance deployments, set this to true to enable the instance to write the automated embeddings View.

If you have multiple mongot instances for replica sets or sharded clusters, ensure that only one instance writes the automated embedding View to prevent duplication or conflicts. Set the value to:

true to designate a mongot instance as the leader responsible for writing the auto-embeddings View.
false to designate a mongot instance as a follower that does not write the auto-embeddings View.

Advanced Settings

advancedConfigs.autoEmbedding.materializedView.numConcurrentChangeStreams

Type: Integer

Necessity: Optional

Default: 2 times the host's CPU core count

Maximum number of steady-state change streams that the materialized view replication process can have outstanding at any one time. Must be a positive integer.

advancedConfigs.autoEmbedding.materializedView.numIndexingThreads

Type: Integer

Necessity: Optional

Default: The host's CPU core count, with a minimum of 1

Number of threads used to write embedding data into the materialized view's indexes. Must be a positive integer.

advancedConfigs.autoEmbedding.materializedView.numEmbeddingThreads

Type: Integer

Necessity: Optional

Default: The host's CPU core count, with a minimum of 1

Number of threads used to request embeddings from the embedding provider. Must be a positive integer.

advancedConfigs.autoEmbedding.materializedView.numConcurrentInitialSyncs

Type: Integer

Necessity: Optional

Default: Half of advancedConfigs.replication.mongodb.numConcurrentInitialSyncs. If the result is less than 1, then it uses 1. If you don not setn advancedConfigs.replication.mongodb.numConcurrentInitialSyncsn also, then it defaults to 1.

Maximum number of Automated Embedding indexes that can run their initial sync at the same time. Limiting concurrency reduces the load placed on the source mongod node and embedding provider during initial builds. Must be a positive integer.

advancedConfigs.autoEmbedding.materializedView.matViewWriterMaxConnections

Type: Integer

Necessity: Optional

Default: 4

Maximum number of connections used to write to the materialized view collection. Must be a positive integer no greater than 16.

advancedConfigs.autoEmbedding.materializedView.mvWriteRateLimitRps

Type: Integer

Necessity: Optional

Default: No limit

Maximum number of bulk write commits per second to the materialized view collection on this node. Use this setting to limit write throughput to the source mongod node. Must be a positive integer.

advancedConfigs.autoEmbedding.materializedView.embeddingProviderRpsLimit

Type: Integer

Necessity: Optional

Default: No limit

Maximum number of requests per second this node can send to the embedding provider. This is a node-level limit. Must be a positive integer no greater than 100.

Advanced Indexing Settings

advancedConfigs.indexing.lucene.refresh.intervalMs

Type: Integer

Necessity: Optional

Default: 1000

Interval, in milliseconds, that mongot waits before refreshing an index to make recently indexed changes visible to queries. Lower values reduce the delay between writing a document and being able to query it, at the cost of more frequent refresh work. Must be a positive integer.

advancedConfigs.indexing.lucene.mergePolicy.tiered.vectorMergePolicy.mergeBudgetMb

Type: Integer

Necessity: Optional

Default: 10% of the host's total memory

Memory budget, in megabytes, available to background merges of vector index segments. A larger budget allows more segments to be merged together at once, which can improve query performance but uses more memory during merges. Must be a positive integer.

advancedConfigs.indexing.lucene.mergeScheduler.concurrent.maxThreadCount

Type: Integer

Necessity: Optional

Default: The number of CPU cores available to the host

Maximum number of threads that can perform index segment merges concurrently. Higher values allow more merges to run in parallel. Must be a positive integer.

advancedConfigs.indexing.lucene.fieldLimit

Type: Integer

Necessity: Optional

Default: No limit

Maximum number of indexed fields allowed in an index. Use this setting to guard against unbounded field growth in indexes. Must be at least 3.

Advanced Querying Settings

advancedConfigs.querying.lucene.maxClauseLimit

Type: Integer

Necessity: Optional

Default: 1024

Maximum number of clauses a single query can expand to. mongot rejects queries that expand beyond this limit. Raising this limit allows larger queries but increases their memory and CPU cost. Must be a positive integer.

advancedConfigs.querying.lucene.vectorFloorSegmentMB

Type: Double

Necessity: Optional

Default: 64.0

Floor segment size, in megabytes, used by the merge policy for MongoDB Vector Search indexes. mongot merges segments smaller than advancedConfigs.querying.lucene.vectorFloorSegmentMB together more aggressively to reduce the total number of segments and improve query performance. Value must be a positive number.

Advanced Replication Settings

advancedConfigs.replication.mongodb.numConcurrentInitialSyncs

Type: Integer

Necessity: Optional

Default: The lesser of the host's CPU core count and 2

Maximum number of indexes that can run their initial sync at the same time. Limiting concurrency reduces the load placed on the source mongod node while many indexes build simultaneously. Must be a positive integer.

advancedConfigs.replication.mongodb.numConcurrentChangeStreams

Type: Integer

Necessity: Optional

Default: 2 times the host's CPU core count

Maximum number of steady-state change streams that can have outstanding requests to the source mongod node at any one time. This setting controls how many indexes can pull updates concurrently after their initial sync completes. Must be a positive integer.

advancedConfigs.replication.mongodb.numIndexingThreads

Type: Integer

Necessity: Optional

Default: Half the host's CPU core count, with a minimum of 1

Number of threads used to write replicated documents and changes into indexes. Higher values can improve indexing throughput but might increase CPU and memory usage. Value must be a positive integer.

advancedConfigs.replication.mongodb.numConcurrentSynonymSyncs

Type: Integer

Necessity: Optional

Default: 2

Maximum number of synonym source collections that can sync concurrently. Must be a positive integer.

Advanced FTDC Settings

advancedConfigs.ftdc.enabled

Type: Boolean

Necessity: Optional

Default: true

Flag that enables full-time diagnostic data capture (FTDC). FTDC diagnostic data collection is enabled by default. When false, mongot creates no FTDC reporter at bootstrap, so it captures no diagnostic data.

advancedConfigs.ftdc.directorySizeMb

Type: Integer

Necessity: Optional

Default: 100

Maximum total size, in megabytes, of the FTDC archive directory. Must be at least 10 and greater than advancedConfigs.ftdc.fileSizeMb.

advancedConfigs.ftdc.fileSizeMb

Type: Integer

Necessity: Optional

Default: 10

Maximum size, in megabytes, of an individual FTDC archive file. Must be at least 1 and less than advancedConfigs.ftdc.directorySizeMb.

advancedConfigs.ftdc.collectionPeriodMillis

Type: Integer

Necessity: Optional

Default: 1000

Sampling interval, in milliseconds, that controls how often mongot collects metrics into FTDC. Must be at least 100.

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