Week 1, Day 3

In-class exercise

Break up into groups of three.

1. Using Barroso, Clidaras, and Hölzle’s categories of platform-level software, cluster-level infrastructure, and application-level software, which level would the following most likely fit:

• Software that logs an error from a specific disk drive.
• Software that collects error logs from every disk drive in the cluster.
• A MySQL database server running on a single machine.
• A package management tool (such as yum, npm, or apt-get) that installs software on a machine.
• A database that supports 10,000 queries per second.
• A messaging utility that distributes 100,000 messages per second.

1. Describe one attack that would be prevented by multi-factor authentication on a userid. Describe another attack that would work even with multi-factor authentication.

Discussion of AWS services

See screen listing all AWS services.

Reading guide for next class

Read the following before coming to the next class:

Condos and clouds, pp. 53–55 (from “SaaS: Front end, back end, and decision support” and stop before “A Quick Refresher on Simple Queuing Theory”).

This section begins with the structure of a typical application for the cloud. Online stores such as Amazon or Indigo might have this structure. Then the article focuses on the front-end portion of the application, which interacts directly with the user and therefore has strong response time requirements.

The key points for this week:

• the general-purpose logic outside the grey box in Figure 3.
• the way a single user request is broken into many simpler services.
• the very tight response times required of the lower level services.

The Datacenter as a Computer, 2d. Ed., Sections 2.3–2.4.

These two pages describe the lower two of the three layers of software (see p. 15 for the definitions of the levels), platform-level ad custer-level. We’ll be going into the concrete details of these layers as the course proceeds, using their counterparts on AWS and Cloud474.

The platform level (2.3) and the resource, hardware, and deployment infrastructures (2.4.1–2.4.3) are mostly the concern of the datacenter operators. We won’t consider them in this course. We will consider the programming framework infrastructure (2.4.4). That is the general-purpose logic from Figure 3 of today’s first article.