Live Migration of Probe-Enabled Load Balanced Endpoints
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Solution Overview
Problem
The live migration of virtual machines in datacenters disrupts health probing processes, leading to potential downtime and inaccuracies in reporting the health status of virtual machines during the migration process, as existing technologies do not effectively manage the transition of probe status from the source to the destination host.
Innovation Solution
The proposed solution involves suspending the evaluation of health probe responses during the live migration period and migrating the probe status from the source to the destination host, ensuring that only healthy probe statuses are transferred to maintain continuity of network flows and minimize downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If health probing continues during live migration, then real-time health monitoring is maintained, but probe responses become inaccurate and false negatives occur
Solution Approach 1:
The system performs preliminary action by suspending health probe evaluation before and during the live migration period. The load balancer proactively identifies the migration event and prevents inaccurate probe responses from being generated during the migration window, thereby avoiding false negatives while maintaining monitoring capability through status migration.
Solution Approach 2:
The load balancer acts as an intermediary between the health probing system and the migrating virtual machine. It intercepts probe requests during migration, suspends their evaluation, and uses the migrated probe status as a mediator to maintain accurate health state information without generating false responses during the migration process.
2Reliability
If probe status is not migrated during live migration, then the destination host has complete health information, but the virtual machine appears unhealthy causing service disruption
Solution Approach 1:
The system performs preliminary action by capturing the probe status before migration begins and proactively migrating it to the destination host. This ensures that the destination host already has the correct health information ready before the virtual machine arrives, preventing service disruption while avoiding information loss.
Solution Approach 2:
The load balancer creates a copy of the probe status state and migrates it to the destination host. This copying mechanism preserves the health status information across the migration boundary, ensuring that the destination host receives accurate health information without requiring the virtual machine to re-establish its health state.
3Measurement precision
If health probing is suspended during migration, then false negatives are avoided, but real-time health monitoring is temporarily interrupted
Solution Approach 1:
The system copies the probe status state during migration rather than suspending monitoring entirely. By migrating the status information, the system maintains continuous health monitoring capability without generating false responses, effectively eliminating the need to choose between accuracy and continuity.
Solution Approach 2:
The load balancer uses the migrated probe status as an intermediary to maintain health monitoring during migration. Instead of suspending monitoring, the system uses the copied status information as a mediator that bridges the gap between source and destination hosts, ensuring continuous accurate monitoring without false negatives.
Data Source
AI summary
Methods, systems, and devices are described herein for modifying the monitoring of the health of a data center IP endpoint (such as VM) during live migration of the data center IP endpoint from a source host to a destination host. In one example, the described techniques may include receiving an indication that a virtual machine is going to be live migrated from a source host to a destination host. Next, evaluation of health probe responses originating from the virtual machine may be suspended for a time period. The time period may be selected based on the live migration. The evaluation of the probe responses originating from the virtual machine may be resumed upon completion of the time period. In some cases, a health probe status of the virtual machine may be migrated from the source host to the destination host.