Failover (HA-cluster) Feature
“High-availability clusters (also known as HA clusters or fail over clusters) are groups of computers (…) that can be reliably utilized with a minimum of down-time. They operate by using high availability software to harness redundant computers in groups or clusters that provide continued service when system components fail. Without clustering, if a server running a particular application crashes, the application will be unavailable until the crashed server is fixed. HA clustering remedies this situation by detecting hardware/software faults, and immediately restarting the application on another system or whole node without requiring administrative intervention, a process known as failover.” (source: Wikipedia)
SMSEagle devices has its own failover mechanism based on HA-cluster. This feature allows you to assure high availability of SMSEagle devices in uptime-critical environments. To enable failover (HA-cluster) you need at least 2 devices (‘aka’ nodes). The failover feature monitors devices and detects faults with the most vital services (web server, database engine, modem software, modem connectivity, SNMP agent, accessibility of whole node).
In the cluster you have one MASTER device and one BACKUP device. HA-cluster is accessed via Virtual IP address.
Every node in HA-cluster can have one of three states:
- MASTER: main healthy node in a cluster, by default accessible through Virtual IP
- BACKUP: second healthy node in a cluster, ready and waiting for replacing Master when needed
- FAULT: node with detected service fault
When HA-cluster detects failure of at least one function of MASTER device it immediately switches cluster’s IP assignment to the BACKUP device (node) providing continuous usage of the SMSEagle HA-cluster for a user.
How to configure Failover (HA-cluster) on SMSEagle device:
Failover cluster can be easily configured using Web-GUI. For each device in failover cluster:
- enter virtual IP address in the field “Virtual IP Address”
- enter Master and Backup IP addresses (these should be physical addresses of your devices)
- set “Enable Failover cluster” to “Yes”
- optionaly you can enable database replication between nodes (feature available only in devices with hardware Rev.2 and higher)
Save configuration. Reboot each device after saving. The configuration should be exactly the same on both devices in HA-cluster.