Command Center Administration

Starting and Stopping Greenplum Command Center
•Starting and Stopping Command Center Agents
•Starting and Stopping Command Center Console

Starting and Stopping Command Center Agents
Whenever the Greenplum Database server configuration parameter gp_enable_gpperfmon is enabled in the master postgresql.conf file, the Command Center agents will run and collect data. These agents are automatically stopped and started together along with the Greenplum Database instance.

If you wish to disable the Command Center data collection agents, you must disable the gp_enable_gpperfmon parameter, and restart the Greenplum Database instance.

Starting and Stopping Command Center Console
You can start, stop and restart Greenplum Command Center Console instances with the following commands:

$ gpcmdr --start ["instance name"]
$ gpcmdr --stop ["instance name"]
$ gpcmdr --restart ["instance name"]

If you do not specify an instance name, all instances are started, stopped or restarted at once. You can check the status of instances using:
$ gpcmdr --status ["instance name"]

Configuring Greenplum Command Center
Configuration parameters for Greenplum Command Center are stored in the following configuration files:

Agent Configuration
Changes to these files require a restart of the Greenplum Database instance
(gpstop -r).
•$MASTER_DATA_DIRECTORY/gpperfmon/conf/gpperfmon.conf
•$MASTER_DATA_DIRECTORY/postgresql.conf

Console Configuration
Changes to these files require a restart of Command Center Console (gpcmdr --restart).
•$GPPERFMONHOME/instances/instance_name/conf/gpperfmonui.conf
•$GPPERFMONHOME/instances/instance_name/conf/lighttpd.conf

You should not need to manually edit any of the files. Running the Command Center setup utility will make all the necessary modifications to these configuration files.

Command Center Agent Administration
This section describes basic agent administration tasks, including adding hosts and viewing agent log files.

Adding and Removing Hosts
Segment agents on new hosts are detected automatically by the master agent. Whenever gp_enable_gpperfmon is enabled on the master, the master monitor agent automatically detects, starts, and begins harvesting data from new segment agents.

To verify the addition of a new monitored host, you can check for the new hostname in the Greenplum Command Center Console System Metrics view described in the Greenplum Command Center Console online help. Alternately, you can query the system_now table for the row containing current metrics for each host. For example:

=# SELECT * FROM system_now WHERE hostname='new_hostname';

Viewing and Maintaining Master Agent Log Files
Log messages for the master agent are written to $MASTER_DATA_DIRECTORY/gpperfmon/logs/gpmmon.log by default. To change the log file location, edit the log_location parameter in gpperfmon.conf.

On the segment hosts, agent log messages are written to a gpsmon.log file in the segment instance’s data directory. For a host with multiple segments, the agent log file is located in the data directory of the first segment, as listed in the gp_configuration table by dbid. If the segment agent is unable to log into this directory, it will log messages to the home directory of the user running Command Center (typically gpadmin).

Configuring Log File Rollover
At higher logging levels, the size of the log files may grow dramatically. To prevent the log files from growing to excessive size, you can add an optional log rollover parameter to gpperfmon.conf. The value of this parameter is measured in bytes. For example:
max_log_size = 10485760

With this setting, the log files will grow to 10MB before the system rolls over the log file. The timestamp is added to the log file name when it is rolled over. Administrators must periodically clean out old log files that are no longer needed.

Command Center Database Administration
Data collected by Command Center agents is stored in a dedicated database called gpperfmon within the Greenplum Database instance. This database requires the typical database maintenance tasks such as clean up of old historical data and periodic ANALYZE.

Connecting to the Command Center Database
Database administrators can connect directly to the Command Center database (gpperfmon) using any Greenplum Database-compatible client program (such as psql). For example:

$ psql -d gpperfmon -h master_host -p 5432 -U gpadmin

Backing Up and Restoring the Command Center Database
The history tables of the Command Center database (gpperfmon) can be backed up and restored using the Greenplum Database parallel backup and restore utilities (gp_dump, gp_restore, gpcrondump, gpdbrestore). 

Because the Command Center database has a low number of tables, you may prefer to devise a backup plan using the table-level backup features of gp_dump. For example, you can create scripts to run gp_dump to back up the monthly partitions of the historical data tables on a monthly schedule. Alternately, you can back up your Command Center database at the database level.

Maintaining the Historical Data Tables
All of the *_history tables stored in the Command Center database (gpperfmon) are partitioned into monthly partitions. A January 2010 partition is created at installation time as a template partition (it can be deleted once some current partitions are created). The Command Center agents automatically create new partitions in two month increments as needed. Administrators must periodically drop partitions for the months that are no longer needed in order to maintain the size of the Command Center database.

Web Server Administration
The Lighttpd web server and web service middleware are installed in the www directory of your Greenplum Command Center installation. For detailed information on Lighttpd administration, see http://www.lighttpd.net/.

Configuring the Web Server
The Lighttpd web server configuration file is stored in $GPPERFMONHOME/instances/instance_name/conf/lighttpd.conf. Some of the parameters in this configuration file are set by the gpcmdr setup utility, including the web server port and SSL options. See “Web Server Parameters (lighttpd.conf)” on page 30 for a description of the parameters in this file.

You should not need to manually edit this file, if you do, you may break some functionality. Contact EMC Support if you want to make custom modifications to this file.

Viewing and Maintaining Web Server Log Files
Web server access and error logs are written to $GPPERFMONHOME/instances/instance_name/logs. These two logs are:
  • lighttpd-access.log
  • lighttpd-error.log
If you experience errors viewing the Greenplum Command Center Console, refer to these logs for more information.
To prevent web server logs from growing to excessive size, you can set up log file rotation using logrotate or cronolog, both of which are widely used with Lighttpd.

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