Meta Service configuration¶

Nebula Graph provides two initial configuration files for the Meta Service: nebula-metad.conf.default and nebula-metad.conf.production. You can use them in different scenarios. The default file path is /usr/local/nebula/etc/.

How to use the configuration files¶

The Meta Service gets its configuration from the nebula-metad.conf file. You have to remove the suffix .default or .production from an initial configuration file for the Meta Service to apply the configuration defined in it.

If you have modified the configuration in the file and want new configuration to take effect, add --local_conf=true at the top of the file. Otherwise, Nebula Graph reads the cached configuration.

About parameter values¶

If a parameter is not set in the configuration file, Nebula Graph uses the default value.

NOTE: The default value of a parameter in Nebula Graph may be different from the predefined value in the .default and .production files.

The predefined parameters in nebula-metad.conf.default and nebula-metad.conf.production are different. And not all parameters are predefined. This topic uses the parameters in nebula-metad.conf.default.

Nebula Graph provides two initial configuration files for the Meta Service: nebula-metad.conf.default and nebula-metad.conf.production. You can use them in different scenarios. The default file path is /usr/local/nebula/etc/.

Basic configurations¶

Name	Predefine Value	Descriptions
`daemonize`	`true`	When set to `true`, the process is a daemon process.
`pid_file`	`pids/nebula-metad.pid`	File to host the process ID.
`timezone_name`	-	Specifies the Nebula Graph time zone. This parameter is not predefined in the initial configuration files. You can manually set it if you need it. The system default value is `UTC+00:00:00`. For the format of the parameter value, see Specifying the Time Zone with TZ. For example, `--timezone_name=CST-8` represents the GMT+8 time zone.

NOTE:

While inserting time-type property values except timestamps, Nebula Graph transforms them to a UTC time according to the time zone specified with the timezone_name parameter in the configuration files. The time-type values returned by nGQL queries are all UTC time.

timezone_name is only used to transform the data stored in Nebula Graph. Other time-related data of the Nebula Graph processes still uses the default time zone of the host, such as the log printing time.

Logging configurations¶

Name	Predefine Value	Descriptions
`log_dir`	`logs`	Directory to the Meta Service log. We recommend that you put logs on a different hard disk from the `data_path`.
`minloglevel`	`0`	Specifies the minimum log level. Available values are `0` (INFO), `1` (WARNING), `2` (ERROR), and `3` (FATAL). We suggest that you set `minloglevel` to `0` for debugging and `1` for production. When you set it to `4`, Nebula Graph does not print any logs.
`v`	`0`	Specifies the verbose log level. Available values are 0-4. The larger the value, the more verbose the log.
`logbufsecs`	`0`	Specifies the maximum time to buffer the logs. The configuration is measured in seconds.
`stdout_log_file`	`metad-stdout.log`	Specifies the filename for the stdout log.
`stderr_log_file`	`metad-stderr.log`	Specifies the filename for the stderr log.
`stderrthreshold`	`2`	Specifies the minimum level to copy the log messages to stderr.

Networking configurations¶

Name	Predefine Value	Descriptions
`meta_server_addrs`	`127.0.0.1:9559`	Specifies the IP addresses and ports of all Meta Services. Separate multiple addresses with commas.
`local_ip`	`127.0.0.1`	Specifies the local IP for the Meta Service.
`port`	`9559`	Specifies RPC daemon listening port. The external port for the Meta Service is predefined to `9559`. The internal port is predefined to `port + 1`, i.e., `9560`. Nebula Graph uses the internal port for multi-replica interactions.
`ws_ip`	`0.0.0.0`	Specifies the IP address for the HTTP service.
`ws_http_port`	`19559`	Specifies the port for the HTTP service.
`ws_h2_port`	`19560`	Specifies the port for the HTTP2 service.
`heartbeat_interval_secs`	`10`	Specifies the default heartbeat interval in seconds. Make sure the `heartbeat_interval_secs` values for all services are the same, otherwise Nebula Graph CANNOT work normally.

NOTE: We recommend that you use the real IP address in your configuration because sometimes 127.0.0.1 can not be parsed correctly.

Storage configurations¶

Name	Predefine Value	Descriptions
`data_path`	data/meta (i.e. /usr/local/nebula/data/meta/)	Directory for cluster metadata persistence

Misc configurations¶

Name	Predefine Value	Descriptions
`default_parts_num`	`100`	Specifies the default partition number when you create a new graph space.
`default_replica_factor`	`1`	Specifies the default replica factor number when you create a new graph space.

RocksDB options¶

Name	Predefine Value	Descriptions
`rocksdb_wal_sync`	`true`	Enable or disable RocksDB WAL synchronization. Available values are `true` (enable) and `false` (disable).

Last update: April 13, 2021