# Reliable Virtual Machine Placement and Routing in Clouds

## TL;DR

This paper addresses the complex problem of reliably placing virtual machines and routing connections in cloud environments, proposing exact and heuristic solutions for ensuring high availability and low latency under failure conditions.

## Contribution

It introduces a novel formulation for VM placement and routing with availability constraints, providing both exact and heuristic algorithms and analyzing their performance.

## Key findings

- Proposed algorithms outperform existing heuristics in simulations.
- Validated the NP-hardness of VM placement and routing problems.
- Achieved high reliability with optimized placement and routing strategies.

## Abstract

In current cloud computing systems, when leveraging virtualization technology, the customer's requested data computing or storing service is accommodated by a set of communicated virtual machines (VM) in a scalable and elastic manner. These VMs are placed in one or more server nodes according to the node capacities or failure probabilities. The VM placement availability refers to the probability that at least one set of all customer's requested VMs operates during the requested lifetime. In this paper, we first study the problem of placing at most H groups of k requested VMs on a minimum number of nodes, such that the VM placement availability is no less than $\delta$, and that the specified communication delay and connection availability for each VM pair under the same placement group are not violated. We consider this problem with and without Shared-Risk Node Group (SRNG) failures, and prove this problem is NP-hard in both cases. We subsequently propose an exact Integer Nonlinear Program (INLP) and an efficient heuristic to solve this problem. We conduct simulations to compare the proposed algorithms with two existing heuristics in terms of performance. Finally, we study the related reliable routing problem of establishing a connection over at most w link-disjoint paths from a source to a destination, such that the connection availability requirement is satisfied and each path delay is no more than a given value. We devise an exact algorithm and two heuristics to solve this NP-hard problem, and evaluate them via simulations.