Aws

Amazon S3 is a great place to store static content for your web site. If the content is sensitive you’ll want to prevent the content from being visible while in transit from the S3 servers to the client. The standard way to secure the content during transfer is by https - simply request the content via an https URL. However, this approach has a problem: it does not work for content in S3 buckets that are accessed via a virtual host URL. Here is an examination of the problem and a workaround. ...

If you use AWS’s Elastic Load Balancer to allow your EC2 application to scale, like I do, then you’ll want to know about this gotcha recently reported in the AWS forums. By all appearances, it looks like something that should be fixed by Amazon. Until it is, you can reduce (but not eliminate) your exposure to this problem by keeping a small TTL for your ELB’s DNS CNAME entry. Read on for details. ...

There are many posts about how to mount an EBS volume to your EC2 instance during the startup process. But requiring an instance to use a specific EBS volume has limitations that make the technique unsuitable for large-scale use. In this article I present a more flexible technique that uses an EBS snapshot instead. Update December 2009: Amazon released native support for automatically mounting EBS volumes created from a snapshot, as part of supporting the boot-from-EBS feature. The techniques in this article are no longer necessary. But they’re cool anyway. ...

I discovered an interesting feature of Amazon EC2 Elastic Load Balancing today: you can add an EC2 instance to more than one ELB virtual appliance. Below I demonstrate the steps I took to set up two ELBs each containing the same instance, and afterward I explain how this technique can be used to deliver different classes of service. How to Set Up One Instance Belonging to Multiple ELBs I set this up using the standard EC2 API and EC2 ELB command-line tools. First I launched an instance. I used my favorite Alestic image, the Ubuntu 8.04 Hardy Server AMI: ...

The ElasticFox Firefox extension allows you to tag EC2 instances, EBS volumes, EBS snapshots, Elastic IPs, and AMIs. ElasticFox’s tags are stored locally within Firefox, so if you use ElasticFox from more than one browser your tags from one browser are not visible in any other browser. In this article I demonstrate how to copy tags from one ElasticFox installation to another. Where Are ElasticFox Tags Stored? My article about Tagging EC2 Instances Using Security Groups shows a brief walkthrough of using ElasticFox to tag instances. Under the hood, ElasticFox stores tags in the prefs.js file within your Firefox Profile directory. But instead of poking around in there directly, take a look at Firefox’s built-in interface to these preferences. It’s the about:config screen, and you get there by typing about:config into the address bar: ...

EBS offers the ability to have a “virtual disk drive” whose lifetime is independent of any EC2 instance. You can attach EBS drives to any running instance, and any changes made to the drive will persist even after the instance is terminated. You can also set up an EBS drive to be the root filesystem for an instance - giving you the benefits of an always-on instance but without paying for it when it’s not in use - and this article shows you how to do that. I also explore how to estimate the cost savings you can achieve using this solution. ...

Update March 2012: Amazon published their own official guide to ELB’s architecture and building and testing applications that use it. The official material is very consistent with the presentation offered here, more than two and a half years prior. Elastic Load Balancing is a long-anticipated AWS feature that aims to ease the deployment of highly-scalable web applications. Let’s take a look at how it achieves elasticity, based on experience and based on the information available in the AWS forums (mainly this thread). The goal is to understand how to design and test ELB deployments properly. ...

Update September 2010: AWS has added support for tagging instances, volumes, snapshots, and many other EC2 resource types via the API and the AWS Management Console. The techniques described here are no longer necessary. So you have a bunch of instances running in Amazon EC2 and you want to be able to tell them apart easily. The way to do this is to “tag” each instance with a descriptive tag, such as “database”, “web server”, “memcached”, etc. The easy, human-friendly way to tag your instances is to use ElasticFox, and the robust, programming-friendly way is to use Security Groups. ...

Here you will find practical tips for developers who are using cloud computing. This is me on the Amazon Web Services EC2 support forum, where I’m a frequent poster answering questions and sharing practical advice based on my experience. My nickname there used to be “shl0m0”; you might see that reference in older posts. My experience includes more than 15 years of software development and software architecture. I’ve been building cloud-computing-based applications for clients (including my own company MyDrifts, where I am CTO and co-founder) since 2007.