Network Traffic Management Device Cluster Upgrade Without Downtime
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Solution Overview
Problem
Traditional methods for upgrading cluster-based network traffic management devices are costly, vulnerable to failures during upgrades, and face challenges in transferring configuration states between clusters with different software or hardware versions, leading to potential connection drops.
Innovation Solution
The approach involves bifurcating the cluster into an 'old' and 'new' virtual cluster, iteratively upgrading members while maintaining seamless connection processing, and using state mirroring to transfer configuration, session, and connection states, allowing for a smooth failover to the new cluster without downtime or data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional upgrading methods are used for cluster-based network traffic management devices, then the upgrade process is simple, but the system experiences downtime and connection drops during the upgrade
Solution Approach 1:
The cluster is segmented into multiple member devices, allowing selective upgrading of individual members while others continue to handle traffic. The upgrade process divides the cluster into active and upgraded groups, enabling continuous operation during the transition.
Solution Approach 2:
Connection state mirroring is performed in advance before the actual upgrade. The upgraded member device receives and mirrors connection states from the member being upgraded, preparing the system for seamless failover before any traffic interruption occurs.
2Reliability
If cluster members are upgraded one at a time, then system availability is maintained, but the complexity of managing state transfer and failover increases
Solution Approach 1:
The system implements feedback mechanisms where upgraded member devices continuously mirror connection states back to the cluster. This feedback loop ensures that state information is synchronized and available for immediate failover if needed, reducing the complexity of manual state management.
Solution Approach 2:
Connection states are copied from members being upgraded to upgraded member devices through mirroring. This copying mechanism automates the state transfer process, eliminating the need for complex manual configuration and reducing upgrade management complexity.
3Ease of operation
If state mirroring is implemented between clusters with different software versions, then seamless failover is enabled, but the risk of version compatibility issues increases
Solution Approach 1:
The patent introduces a state mirroring mechanism that acts as an intermediary between different software versions. The mirroring process transfers connection states through a standardized interface that abstracts version-specific details, enabling compatibility between different software versions while maintaining seamless failover capability.
4Stability of the object's composition
If all cluster members are upgraded simultaneously, then consistency is maintained, but complete system downtime occurs
Solution Approach 1:
The cluster is segmented into multiple member devices that can be upgraded independently. This segmentation allows the upgrade process to proceed in stages rather than all-at-once, maintaining cluster consistency within each segment while avoiding complete system downtime.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining traffic handling capabilities throughout the upgrade process. Upgraded member devices continue to mirror connection states and can immediately take over traffic handling, ensuring that the cluster's useful action continues without interruption.
Data Source
AI summary
A method, system, machine-readable storage medium, and apparatus are directed towards upgrading a cluster by bifurcating the cluster into two virtual clusters, an “old” virtual cluster (old active cluster) and a “new” virtual cluster (new standby cluster), and iteratively upgrading members of the old cluster while moving them into the new cluster. While members are added to the new cluster, existing connections and new connections are seamlessly processed by the old cluster. Optionally, state mirroring occurs between the old cluster and the new cluster once the number of members of the old and new clusters are approximately equal. Once a threshold number of members have been transferred to the new cluster, control and processing may be taken over by the new cluster. Transfer of control from the old cluster to the new cluster may be performed by failing over connectivity from the old cluster to the new cluster.