6.4 Modifying the pg_hba.conf File

Entries in the pg_hba.conf file control network authentication and authorization. The pg_hba.conf file on the PEM server host must allow connections between the PEM server and PEM-HTTPD, the PEM agent, and the monitored servers.

During the PEM server installation process, you are prompted for the IP address and connection information for hosts that will be monitored by PEM; this information is added to the top of the pg_hba.conf file of the PEM backing database (see Figure 6.3).

Figure 6.3 - PEM entries in the pg_hba.conf file.

You may also need to manually modify the pg_hba.conf file to allow connections between the PEM server and other components. For example, if your PEM-HTTPD installation does not reside on the same host as the PEM server, you must modify the pg_hba.conf file on the PEM server host to allowPEM-HTTPD to connect to the server.

By default, the pg_hba.conf file resides in the data directory, under your Postgres installation; for example, on an Advanced Server 10 host, the default location of the pg_hba.conf is:

/opt/edb/as10/data/pg_hba.conf

You can modify the pg_hba.conf file with your editor of choice. After modifying the file, restart the server for changes to take effect.

The following example shows a pg_hba.conf entry that allows an md5 password authenticated connection from a user named postgres, to the postgres database on the host on which the pg_hba.conf file resides. The connection is coming from an IP address of 192.168.10.102:

# TYPE DATABASE USER CIDR-ADDRESS METHOD

 

# IPv4 local connections:

host postgres postgres 192.168.10.102/32 md5

You may specify the address of a network host, or a network address range. For example, if you wish to allow connections from servers with the addresses 192.168.10.23, 192.168.10.76 and 192.168.10.184, enter a CIDR-ADDRESS of 192.168.10.0/24 to allow connections from all of the hosts in that network:

# TYPE DATABASE USER CIDR-ADDRESS METHOD

 

# IPv4 local connections:

host postgres all 192.168.10.0/24 md5

For more information about formatting a pg_hba.conf file entry, please see the PostgreSQL core documentation at:

http://www.postgresql.org/docs/10/static/auth-pg-hba-conf.html

Before you can connect to a Postgres server with PEM, you must ensure that the pg_hba.conf file on both servers allows the connection (see Figure 6.4).

Figure 6.4 – Connect to Server error.

If you receive this error when connecting to the database server, modify the pg_hba.conf file, adding an entry that allows the connection.