FerretDB/website/docs/configuration/flags.md

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Configuration flags

FerretDB provides numerous configuration flags you can customize to suit your needs and environment. You can always see the complete list by using --help flag. To make user experience cloud native, every flag has its environment variable equivalent. There is no configuration file.

:::info Some default values are overridden in our Docker image. :::

General

Flag	Description	Environment Variable	Default Value
-h, --help	Show context-sensitive help
--version	Print version to stdout and exit

PostgreSQL

Flag	Description	Environment Variable	Default Value
--postgresql-url	PostgreSQL connection URL	FERRETDB_POSTGRESQL_URL	postgres://127.0.0.1:5432/postgres
--postgresql-url-file	Path to a file containing the PostgreSQL connection URL. If non-empty, this overrides --postgresql-url.	FERRETDB_POSTGRESQL_URL_FILE

FerretDB uses pgx v5 library for connecting to PostgreSQL. Supported URL query parameters and default values are documented there:

• https://pkg.go.dev/github.com/jackc/pgx/v5/pgconn#ParseConfig
• https://pkg.go.dev/github.com/jackc/pgx/v5#ParseConfig
• https://pkg.go.dev/github.com/jackc/pgx/v5/pgxpool#ParseConfig

Additionally:

• pool_min_conns is set to 10 if unset (overriding pgx's value of 0);
• pool_max_conns is set to 50 if unset (overriding pgx's value of 4);
• application_name is always set to "FerretDB";
• timezone is always set to "UTC".

Interfaces

Flag	Description	Environment Variable	Default Value
--listen-addr	Listen TCP address for MongoDB protocol (set to empty value or - to disable)	FERRETDB_LISTEN_ADDR	127.0.0.1:27017 (:27017 for Docker)
--listen-unix	Listen Unix domain socket path for MongoDB protocol (set to empty value or - to disable)	FERRETDB_LISTEN_UNIX
--listen-tls	Listen TLS address for MongoDB protocol (see here) (set to empty value or - to disable)	FERRETDB_LISTEN_TLS
--listen-tls-cert-file	TLS cert file path	FERRETDB_LISTEN_TLS_CERT_FILE
--listen-tls-key-file	TLS key file path	FERRETDB_LISTEN_TLS_KEY_FILE
--listen-tls-ca-file	TLS CA file path	FERRETDB_LISTEN_TLS_CA_FILE
--listen-data-api-addr	Listen TCP address for HTTP Data API (set to empty value or - to disable)	FERRETDB_LISTEN_DATA_API_ADDR
--listen-mcp-addr	Listen TCP address for HTTP MCP server (set to empty value or - to disable)	FERRETDB_LISTEN_MCP_ADDR
--proxy-addr	Proxy address for non-normal operation mode	FERRETDB_PROXY_ADDR
--proxy-tls-cert-file	Proxy TLS cert file path	FERRETDB_PROXY_TLS_CERT_FILE
--proxy-tls-key-file	Proxy TLS key file path	FERRETDB_PROXY_TLS_KEY_FILE
--proxy-tls-ca-file	Proxy TLS CA file path	FERRETDB_PROXY_TLS_CA_FILE
--debug-addr	Listen address for HTTP handlers for metrics, pprof, etc (set to empty value or - to disable)	FERRETDB_DEBUG_ADDR	127.0.0.1:8088 (:8088 for Docker)

Miscellaneous

Flag	Description	Environment Variable	Default Value
--mode	Operation mode	FERRETDB_MODE	normal
--state-dir	Path to the FerretDB state directory	FERRETDB_STATE_DIR	. (/state for Docker)
--[no-]auth	Enable authentication	FERRETDB_AUTH	enabled
--log-level	Log level: 'debug', 'info', 'warn', 'error'	FERRETDB_LOG_LEVEL	info
--[no-]log-uuid	Add instance UUID to all log messages	FERRETDB_LOG_UUID	disabled
--[no-]metrics-uuid	Add instance UUID to all metrics	FERRETDB_METRICS_UUID	disabled
--otel-service-name	OpenTelemetry service name	FERRETDB_OTEL_SERVICE_NAME	ferretdb
--otel-traces-url	OpenTelemetry OTLP/HTTP traces endpoint URL (e.g. http://host:4318/v1/traces) (set to empty value or - to disable)	FERRETDB_OTEL_TRACES_URL	disabled
--telemetry	Enable or disable basic telemetry	FERRETDB_TELEMETRY	undecided