SDN Master Controller Selection via Resource Monitoring
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Solution Overview
Problem
Standalone SDN controllers lack high availability, leading to unmanaged networks in case of controller failure, as they do not consider the current state of slave controllers when selecting a new master, such as disk usage, which affects their ability to manage network devices.
Innovation Solution
Implement a system where the master SDN controller monitors parameters like processing resource, memory, and disk usage across all controllers, ranks them based on these values, and selects a slave controller with the lowest rank as the new master when its own parameter values exceed predefined limits, ensuring a seamless transition and maintaining network management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standalone SDN controller is used, then the system is simple to deploy, but high availability is lost and network management fails upon controller failure
Solution Approach 1:
The system segments controller functionality into a master controller and multiple slave controllers, each with specific roles. The master controller handles primary management tasks while slave controllers provide backup capacity, allowing the system to maintain functionality even when the master fails. This segmentation enables high availability without requiring a completely redundant complex architecture.
Solution Approach 2:
The system performs preliminary actions by pre-configuring slave controllers with backup capabilities and establishing failover protocols before any failure occurs. Slave controllers monitor their own resource states and prepare to assume master responsibilities, ensuring that when failover is needed, the transition is seamless and maintains network management continuity.
2Reliability
If any slave controller is selected as new master without considering current state, then the failover process is simple, but network management capability may be compromised due to poor resource state
Solution Approach 1:
The master controller continuously monitors resource usage parameters (CPU, memory, disk) of slave controllers and uses this feedback to make intelligent selection decisions. When failover is required, the system selects a slave controller based on its current resource state, preferring those with available capacity. This feedback mechanism ensures that the selected slave can effectively assume master responsibilities while maintaining reasonable selection complexity.
Solution Approach 2:
The system changes the selection criterion from simple priority-based or round-robin methods to parameter-based selection, where slave controllers are evaluated on their current resource utilization parameters. This allows dynamic adaptation to changing system conditions, ensuring that the selected slave has the necessary resources to maintain network management capability.
3Reliability
If the master controller does not monitor slave controller states, then the system operation is simpler, but the ability to select a capable backup master is reduced
Solution Approach 1:
The master controller performs partial monitoring by tracking only the essential resource usage parameters (CPU, memory, disk) of slave controllers rather than comprehensive system states. This selective monitoring provides sufficient information for failover decisions while consuming minimal processing resources, achieving a balance between reliability and operational overhead.
Data Source
AI summary
Examples disclosed herein relate to selection of a master controller in a software defined network (SDN). In an example, a master controller may monitor a parameter on each SDN controller in a team of SDN controllers comprising the master controller, wherein the master controller performs a role of master over a group of network devices. In response to a determination that a value of the parameter on the master controller is above a pre-defined limit, master controller may select another SDN controller from the team. Master controller may assign the role of master over network devices in the group to the selected SDN controller based on a ranking of the network devices, wherein the network devices may be assigned in succession until a limit defined for a value of the parameter on the selected SDN controller is reached.