Securing the gpmon Database User
The Greenplum Database gpmon user is a superuser role used to manage the gpperfmon database. The
gpperfmon_install utility, which must be run before you install Greenplum Command Center Console, creates the gpmon role.
Greenplum Database uses the gpmon role to update the gpperfmon database with data collected by agents running on the segment hosts. The Command Center web server uses the gpmon role to connect to the gpperfmon database as well as databases monitored by the Command Center.
gpperfmon_install creates the gpmon role, it prompts for a password, which it then adds to the
.pgpass file in the gpadmin user’s home directory. The entry in the
.pgpass file is similar to the following:
See The Password File in the PostgreSQL documentation for details about the
.pgpass file is required on the Greenplum Database master host to start the gpperfmon data collection agents. If you run Greenplum Command Center on a different host, you can copy the
.pgpass file to that host, or you can run the Command Center
gpcc management utility with the
-W option to request password entry each time you start or stop Command Center or request status.
$MASTER_DATA_DIRECTORY/pg_hba.conf authentication file,
gpperfmon_install creates these entries:
local gpperfmon gpmon md5 host all gpmon 127.0.0.1/28 md5 host all gpmon ::1/128 md5
If you authenticate users with Kerberos, you can also set up Kerberos authentication for the gpmon role on the Greenplum master and standby hosts. Kerberos authentication is supported with TCP connections only;
local entries use Linux sockets and authenticate with the
.pgpass file password, even if you have enabled Kerberos for
To change the gpmon password, follow these steps:
Log in to Greenplum Database as a superuser and change the gpmon password with the
# ALTER ROLE gpmon WITH ENCRYPTED PASSWORD 'new_password';
On the Greenplum master host, update the password in the
.pgpassfile in the gpadmin home directory (
~/.pgpass). Replace the existing password in the line or lines for gpmon with the new password.
Ensure that the
.pgpassfile is owned by gpadmin and RW-accessible by gpadmin only.
$ chown gpadmin:gpadmin ~/.pgpass $ chmod 600 ~/.pgpass
Restart Greenplum Command Center with the
$ gpcc start
Be sure to also update the
.pgpass file on the standby master host.
If you authenticate Greenplum Database and Command Center users with Kerberos, you can also authenticate the gpmon user with Kerberos.
To prepare for installing Command Center with Kerberos authentication, follow these steps:
Create the gpperfmon database using the Greenplum Database
gpperfmon-installmanagement utility. See Creating the gpperfmon Database.
On the KDC, create a keytab file containing the Kerberos principal for the gpmon user, just as you would for any Kerberos-authenticated client. Install the file on the Greenplum master and standby hosts.
Update the entries for gpmon in the
$MASTER_DATA_DIRECTORY/pg_hba.conffile to use the
host all gpmon 0.0.0.0/0 gss include_realm=0 krb_realm=GPDB.EXAMPLE.COM
pg_hba.confcannot be authenticated with Kerberos. If there is a
localentry for the gpmon user, it will use the
.pgpassfile to authenticate with the database. See The pg_hba.conf file in the PostgreSQL documentation for complete
Log in to the master host as gpadmin and authenticate the gpmon user.
$ kinit gpmon
Install Greenplum Command Center to set up the Kerberos-enabled Command Center.