How-to: Basic HAProxy Active/Backup Example Configuration (keepalived) for CentOS/RHEL 6

I had an earlier post regarding a basic HAProxy install that will work fine if your site(s) can tolerate some down time should something happen to your server/instance running HAProxy. While this might be acceptable for a personal site, it quickly becomes unacceptable should your business rely on your site being up without interruption. Luckily for you, it’s relatively simple to configure an HA pair of HAProxy load balancers.

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Break/Fix: RPM rpmdb: Lock table is out of available locker entries

The full error may look something like this:

-------------------------------------------------------------------------
    rpmdb: Lock table is out of available locker entries
    error: db4 error(22) from db->close: Invalid argument
    error: cannot open Packages index using db3 - Cannot allocate memory (12)
    error: cannot open Packages database in /var/lib/rpm
-------------------------------------------------------------------------

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How-to: Basic HAProxy Example Configuration for CentOS/RHEL 6

This is a basic HAProxy configuration example that should get you up and running with the simplest of setups. This configuration will have the HAProxy Info page listening on 8080 (adjust as needed) with username/password authentication. In addition, it will also look for http://yourip/healthcheck in addition to the TCP 80 HTTP Port Probes. Why is this useful?

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