High availability

High available Tempesta FW cluster in a cloud (see Clouds Wiki page for description of using Tempesta FW in different cloud environments) or on bare metal machines can be configured using keepalived. This doc describes cluster configuration of two machines. Each machine must run Tempesta FW and keepalived. Each keepalived instance sends periodic heartbeat messages to the second instance and run failovering process if the instance doesn't respond. It's recommended to use separate network interfaces for ingress HTTP traffic and internal keepalived (VRRP) traffic: if the cluster receives enormous ingress traffic and uses the same interfaces to process ingress traffic and VRRP, then VRRP messages can be dropped by an interfaces and keepalived won't be able to manage possible server failures.

Keepalived is usually available through standard Linux distribution packages. Use

    # yum install keepalived

to install it in CentOS or

    # apt-get install keepalived

to install it in Debian.

If a server fails, then it must restart all required services. Thus, add keepalived to bootup process by:

    # systemctl enable keepalived

During failover process keepalived communicates over the private network and moves virtual (floating) IP addresses, VIPs, from failed node to live node. The next step is adding the VIPs to primary (external) interfaces:

    # ip addr add local 172.16.0.5 dev eth0

Do the same for 172.16.0.6 on the second node.