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Synchronized Operating State (Erl, Naserpour)

How can the availability and reliability of virtual servers be ensured when high availability and clustering technology is unavailable?

Synchronized Operating State

Problem

A cloud consumer may be prevented from utilizing high availability and clustering technology for its virtual servers or operating systems, thereby making them more vulnerable to failure.

Solution

A composite failover system is created to not rely on clustering or high availability features but instead use heartbeat messages to synchronize virtual servers.

Application

The heartbeat messages are processed by a specialized service agent and are exchanged between hypervisors, the hypervisor and virtual server, and the hypervisor and VIM.
Synchronized Operating State: Special heartbeat agents are employed to monitor heartbeat messages exchanged between the servers.

Special heartbeat agents are employed to monitor heartbeat messages exchanged between the servers.

Synchronized Operating State: The cloud architecture resulting from the application of this pattern.

The cloud architecture resulting from the application of this pattern.

Synchronized Operating State: When the primary virtual server fails, along with its hosted cloud service, heartbeat messages are no longer transmitted. As a result, the hypervisor recognizes the failure and switches activity to the secondary virtual server that maintains the synchronized state. After the primary virtual server is back online, the hypervisor creates a new secondary for the new primary, and proceeds to save it as a synchronized non-active state.

When the primary virtual server fails, along with its hosted cloud service, heartbeat messages are no longer transmitted. As a result, the hypervisor recognizes the failure and switches activity to the secondary virtual server that maintains the synchronized state. After the primary virtual server is back online, the hypervisor creates a new secondary for the new primary, and proceeds to save it as a synchronized non-active state.

NIST Reference Architecture Mapping

This pattern relates to the highlighted parts of the NIST reference architecture, as follows:

Synchronized Operating State: NIST Reference Architecture Mapping
Synchronized Operating State: NIST Reference Architecture Mapping