Meta Service configuration¶

NebulaGraph provides two initial configuration files for the Meta Service, nebula-metad.conf.default and nebula-metad.conf.production. Users can use them in different scenarios conveniently. The default file path is /usr/local/nebula/etc/.

Caution

It is not recommended to modify the value of local_config to false. If modified, the NebulaGraph service will first read the cached configurations, which may cause configuration inconsistencies between clusters and cause unknown risks.
It is not recommended to modify the configurations that are not introduced in this topic, unless you are familiar with the source code and fully understand the function of configurations.

How to use the configuration files¶

To use the initial configuration file, choose one of the above two files and delete the suffix .default or .production from the initial configuration file for the Meta Service to apply the configurations defined in it.

About parameter values¶

If a parameter is not set in the configuration file, NebulaGraph uses the default value. Not all parameters are predefined. And the predefined parameters in the two initial configuration files are different. This topic uses the parameters in nebula-metad.conf.default.

Caution

Some parameter values in the configuration file can be dynamically modified during runtime. We label these parameters as Yes that supports runtime dynamic modification in this article. When the local_config value is set to true, the dynamically modified configuration is not persisted, and the configuration will be restored to the initial configuration after the service is restarted. For more information, see Modify configurations.

For all parameters and their current values, see Configurations.

Basics configurations¶

Name	Predefined value	Description	Whether supports runtime dynamic modifications
`daemonize`	`true`	When set to `true`, the process is a daemon process.	No
`pid_file`	`pids/nebula-metad.pid`	The file that records the process ID.	No
`timezone_name`	-	Specifies the NebulaGraph 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=UTC+08:00` represents the GMT+8 time zone.	No

Note

While inserting property values of time types, NebulaGraph transforms time types (except TIMESTAMP) to the corresponding UTC according to the time zone specified by timezone_name. The time-type values returned by nGQL queries are all UTC time.
timezone_name is only used to transform the data stored in NebulaGraph. Other time-related data of the NebulaGraph processes still uses the default time zone of the host, such as the log printing time.

License configurations¶

Enterpriseonly

The license configurations are for the Enterprise Edition only.

Name	Predefined value	Description	Whether supports runtime dynamic modifications
`license_manager_url`	-	The address of license manager. Set the value to the host IP and port number `9119` where the license management tool is located in the Meta service configuration file of NebulaGraph (`nebula-metad.conf`), e.g. `192.168.8.100:9119`.	No

Logging configurations¶

Name	Predefined value	Description	Whether supports runtime dynamic modifications
`log_dir`	`logs`	The directory that stores the Meta Service log. It is recommended to put logs on a different hard disk from the data.	No
`minloglevel`	`0`	Specifies the minimum level of the log. That is, log messages at or above this level. Optional values are `0` (INFO), `1` (WARNING), `2` (ERROR), `3` (FATAL). It is recommended to set it to `0` during debugging and `1` in a production environment. If it is set to `4`, NebulaGraph will not print any logs.	Yes
`v`	`0`	Specifies the detailed level of VLOG. That is, log all VLOG messages less or equal to the level. Optional values are `0`, `1`, `2`, `3`, `4`, `5`. The VLOG macro provided by glog allows users to define their own numeric logging levels and control verbose messages that are logged with the parameter `v`. For details, see Verbose Logging.	Yes
`logbufsecs`	`0`	Specifies the maximum time to buffer the logs. If there is a timeout, it will output the buffered log to the log file. `0` means real-time output. This configuration is measured in seconds.	No
`redirect_stdout`	`true`	When set to `true`, the process redirects the`stdout` and `stderr` to separate output files.	No
`stdout_log_file`	`metad-stdout.log`	Specifies the filename for the `stdout` log.	No
`stderr_log_file`	`metad-stderr.log`	Specifies the filename for the `stderr` log.	No
`stderrthreshold`	`3`	Specifies the `minloglevel` to be copied to the `stderr` log.	No
`timestamp_in_logfile_name`	`true`	Specifies if the log file name contains a timestamp. `true` indicates yes, `false` indicates no.	No

Networking configurations¶

Name	Predefined value	Description	Whether supports runtime dynamic modifications
`meta_server_addrs`	`127.0.0.1:9559`	Specifies the IP addresses and ports of all Meta Services. Multiple addresses are separated with commas.	No
`local_ip`	`127.0.0.1`	Specifies the local IP for the Meta Service. The local IP address is used to identify the nebula-metad process. If it is a distributed cluster or requires remote access, modify it to the corresponding address.	No
`port`	`9559`	Specifies RPC daemon listening port of the Meta service. 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.	No
`ws_ip`	`0.0.0.0`	Specifies the IP address for the HTTP service.	No
`ws_http_port`	`19559`	Specifies the port for the HTTP service.	No
`ws_storage_http_port`	`19779`	Specifies the Storage service listening port used by the HTTP protocol. It must be consistent with the `ws_http_port` in the Storage service configuration file. This parameter only applies to standalone NebulaGraph.	No
`heartbeat_interval_secs`	`10`	Specifies the default heartbeat interval. Make sure the `heartbeat_interval_secs` values for all services are the same, otherwise NebulaGraph CANNOT work normally. This configuration is measured in seconds.	Yes

Caution

The real IP address must be used in the configuration file. Otherwise, 127.0.0.1/0.0.0.0 cannot be parsed correctly in some cases.

Storage configurations¶

Name	Predefined Value	Description	Whether supports runtime dynamic modifications
`data_path`	`data/meta`	The storage path for Meta data.	No

Misc configurations¶

Name	Predefined Value	Description	Whether supports runtime dynamic modifications
`default_parts_num`	`100`	Specifies the default partition number when creating a new graph space.	No
`default_replica_factor`	`1`	Specifies the default replica number when creating a new graph space.	No

RocksDB options configurations¶

Name	Predefined Value	Description	Whether supports runtime dynamic modifications
`rocksdb_wal_sync`	`true`	Enables or disables RocksDB WAL synchronization. Available values are `true` (enable) and `false` (disable).	No

Black box configurations¶

Enterpriseonly

The Nebula-BBox configurations are for the Enterprise Edition only.

Name	Predefined Value	Description	Whether supports runtime dynamic modifications
`ng_black_box_switch`	`true`	Whether to enable the Nebula-BBox feature.	No
`ng_black_box_home`	`black_box`	The name of the directory to store Nebula-BBox file data.	No
`ng_black_box_dump_period_seconds`	`5`	The time interval for Nebula-BBox to collect metric data. Unit: Second.	No
`ng_black_box_file_lifetime_seconds`	`1800`	Storage time for Nebula-BBox files generated after collecting metric data. Unit: Second.	Yes

Last update: July 5, 2023