keepalived #3


keepalived is used for monitoring real servers within a Linux Virtual
Server (LVS) cluster. keepalived can be configured to remove real
servers from the cluster pool if it stops responding, as well as send
a notification email to make the admin aware of the service failure.
In addition, keepalived implements an independent Virtual Router
Redundancy Protocol (VRRPv2; see rfc2338 for additional info)
framework for director failover.


Keepalived is a routing software written in C. The main goal of this project is
to provide simple and robust facilities for loadbalancing and high-availability
to Linux system and Linux based infrastructures. Loadbalancing framework relies
on well-known and widely used Linux Virtual Server (IPVS) kernel module
providing Layer4 loadbalancing. Keepalived implements a set of checkers to
dynamically and adaptively maintain and manage loadbalanced server pool
according their health. On the other hand high-availability is achieved by VRRP
protocol. VRRP is a fundamental brick for router failover. In addition,
Keepalived implements a set of hooks to the VRRP finite state machine providing
low-level and high-speed protocol interactions. Keepalived frameworks can be
used independently or all together to provide resilient infrastructures.


Once ready, deploy as follows:

juju deploy keepalived
juju add-relation haproxy keepalived


(string) Virtual IP/netmask that will be moved between instances, e.g.:
(int) Virtual router identifier - a number between 1 and 255 that's unique within the network segment