A Blog of the ZHAW Zurich University of Applied Sciences
There are many different technologies which can increase availability of a cloud infrastructure. In our newest Techcouting paper we evaluate several HA technologies in order to define a HA architecture for an OpenStack deployment which is part of the XiFi project. HA technologies can be grouped in the following classes: Resource monitors that check if […]
Overview Cloud computing means: On-demand self service Virtualization Elastic resource provisioning Cloud computing service is comparable to public utility services like gas, telephone or water supply. Economical value of cloud computing service is determined by reliability, availability and maintainability (RAM) characteristics. Availability impacts the value of cloud computing as it is perceived by end users. […]
In this part of the Dependability Modeling article series we explain how a test framework on an OpenStack architecture can be established. The test procedure has 4 steps: in a first step, we implement the OpenStack environment following the planned system architecture. In the second step we calculate the probabilities of component outages during a given timeframe (e. g. 1 year). Then we start a Chaos Monkey script which “attacks” (randomly disables) the components of the system environment using the calculated probabilities as a base for the attack. As a last step we measure the impact of the Chaos Monkey attack according to the table of failure impact sizes we created in part 2. The impact of the attack should be stored as dataset in a database. Steps 1-4 form one test run. Multiple test runs can be performed on multiple architectures to create a empirical data which allows us to rate the different OpenStack architectures according to their availability.
In the previous article we defined use cases for an OpenStack implementation according to the usage scenario in which the OpenStack environment is deployed. In this part of the Dependability Modeling article series we will show how these use cases relate to functions and services provided by the OpenStack environment and create a set of dependabilities between use cases, functions, services and system components. From this set we will draw the dependency graph and make the impact of component outages computable.
Dependability Modeling is carried out in 4 steps: model the user intercations, model the system functions, model the system services and then model the system components which make system services available. In the first part we will define which interactions could be expected from end users of the OpenStack cloud platform and construct the first part of the dependability graph. Once the dependapility model is constructed, a Dependability Analysis will be performed and several OpenStack HA architectures will be rated according to their outage risk.
In a former article we spoke about testing High Availability in OpenStack with the Chaos Monkey. While the Chaos Monkey is a great tool to test what happens if some system components fail, it does not reveal anything about the general strengths and weaknesses of different system architectures. In order to determine if an architecture with 2 redundant controller nodes and 2 compute nodes offers a higher availability level than an architecture with 3 compute nodes and only 1 controller node, a framework for testing different architectures is required. The “Dependability Modeling Framework” seems to be a great opportunity to evaluate different system architectures on their ability to achieve availability levels required by end users.
While the [ICCLab presented](http://ec.europa.eu/information_society/events/cf/ictpd12/document.cfm?doc_id=23258) at the [ICT Proposer’s Day in Warsaw](http://ec.europa.eu/information_society/events/ictproposersday/2012/index_en.htm), a very interesting announcement was made in relation to Europe’s strategy on Cloud Computing.
On Thursday, the vice president of the European commission, [Neelie Kroes](http://en.wikipedia.org/wiki/Neelie_Kroes), announced [further details](http://europa.eu/rapid/pressReleasesAction.do?reference=IP/12/1025&format=HTML&aged=0&language=EN&guiLanguage=en) on the European Cloud Partnership.
This is a brief summary of the [EU Report:”Advances in Clouds: Report from the CLOUD Computing Expert Working Group.”](http://cordis.europa.eu/fp7/ict/ssai/docs/future-cc-2may-finalreport-experts.pdf) In this report a set of appointed Cloud experts have studied the current cloud computing landscape and have came out with a set of recommendations for advancing the future cloud. They note a large number of challenges present today in cloud computing and where tackled provide an opportunity to European innovators.