多層式網路應用服務之雲端多功能資源管理系統

Multi-objective Resource Management System for Multi-tier Web Service Based on Public Cloud

侯宗佑(Hou, Zong You)

指導教授 ： 黃能富

國立清華大學/電機資訊學院/資訊工程學系/碩士(2015年)

摘要

透過Infrastructure as a service (IaaS)，使用者可以依據自己系統的需求，在任何的時間點租賃不同規格或是數量的虛擬機器來動態的改變系統規模。基於這個優點，許多網路應用服務都已經將系統的佈建從實體伺服器轉移到了IaaS的公有雲環境上。在多層式網路應用服務系統中，通常同時存在可複製和不可複製的應用程式。對於可複製的應用來說，透過增加VM數量達到橫向的擴展相對的簡單。對於像是主資料庫這種因為架構限制而只能單一存在的應用，就只能執行縱向擴展。但是在公有雲的環境中，目前只能透過VM替換來達到縱向擴展的效果，而這又會造成明顯的服務中斷。因此，目前的雲端資源管理服務幾乎都不提供自動縱向擴展的功能，造成多層式網路應用服務很快就會遇到自動擴展的瓶頸
在此篇論文中，為了突破這個自動擴展的瓶頸，我們設計並實作了針對佈建於公有雲的網路應用的資源管理系統。我們實作了模糊控制模組用以處理資源管理的問題。系統也同時具備橫向及縱向擴展的功能，並且我們針對了資料庫實做了動態遷移的機制，用來減輕在對資料庫進行縱向擴展時造成的服務中斷。我們也透過真實的多層式網路應用系統KITs Cloud，來進行實驗分析。實驗結果證明了在公有雲中，多層式系統在缺乏縱向擴展的情況下很快就會達到自動擴展的限制。同時實驗也證明了，相較於目前的自動擴展服務，我們的系統大幅提升了網路應用系統的擴展性。

關鍵字

基礎設施即服務 ； 網路應用服務 ； 自動擴展 ； 即時轉移 ； 公有雲

並列摘要

Infrastructure as a service (IaaS), which provides consumers to rent VMs with different volume and number, allows users to adjust the scale of their application dynamically based on their requirement. Many web service providers have outsourced their application deployment to the IaaS-provided public cloud environment. In a multi-tier web service system, usually there exists both replicable and non-replicable applications. It is relatively simple to perform automatic horizontal scale out for replicable applications. As for non-replicable applications due to the architecture restriction like master database, vertical scaling is required. Nevertheless, replacement is currently the only way to perform vertical scaling in public cloud. This will cause apparent service interruption to the client. Hence, current cloud resource management services do not provide the automation of scale up process. Based on this issue, the web service systems will soon reach their scalability limitation even they adopt the resource management service.
In this thesis, to overcome the scalability limitation, we design and implement a multi-objective resource management system for web service deployed in public cloud. We implement a fuzzy logic controller to deal with the provisioning problem. Both horizontal and vertical scaling are developed in our system. We also implement live migration for database, in order to minimize the service down time when performing vertical scaling. Experiments are conducted with a real-world multi-tier web service, KITs Cloud. The result proves our proposed requirement of automatic vertical scaling for multi-tier web service. Comparing to existing auto-scaling service, our system largely improves the scalability as well.

並列關鍵字

IaaS ； Web Service ； Auto Scaling ； Live Migration ； Public Cloud

參考文獻

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