Alestic.com - A Personal AWS Blog by Eric Hammond

Amazon has announced a new AWS region in Sydney, Australia with the name ap-southeast-2.

The official Ubuntu AMI lookup pages (1, 2) don’t seem to be showing the new location yet, but the official Ubuntu AMI query API does seem to be working, so the new ap-southeast-2 Ubuntu AMIs are available for lookup on Alestic.com.

[Update 2012-11-13: Canonical has fixed the primary Ubuntu AMI lookup page and I understand it should remain more up to date going forward, but the other page is still missing ap-southeast-2]

Point and Click

At the top right of most pages on Alestic.com is an “Ubuntu AMIs” section. Simply select the EC2 region from the pulldown (say “ap-southeast-2” for Sydney, Australia) and you will see a list of the official 64-bit Ubuntu AMI ids for the various active Ubuntu releases.

You may be able to save on future EC2 expenses by selling an unused Reserved Instance for less than its true value or even $0.01, provided it is in the “Heavy Utilization” class.

In the description of the Heavy Utilization Reserved Instance, is this statement:

you pay […] a significantly lower hourly usage fee, and you’re charged that lower hourly rate for every hour in the Reserved Instance term you purchase [emphasis added]

What may not be clear to the casual reader is the fact that when you purchase a Heavy Utilization Reserved Instance, you commit not only to paying the one-time up front cost, but you are also committing to paying the hourly charge for every hour of every month, even if you are not running a matching instance!

The Light Utilization and Medium Utilization descriptions state:

When you need an AWS command line toolset not provided by Ubuntu packages, you can download the tools directly from Amazon and install them locally.

In a previous article I provided instructions on how to install AWS command line tools using Ubuntu packages. That method is slightly easier to set up and easier to upgrade when Ubuntu releases updates. However, the Ubuntu packages aren’t always up to date with the latest from Amazon and there are not yet Ubuntu packages published for every AWS command line tools you might want to use.

Unfortunately, Amazon does not have one single place where you can download all the command line tools for the various services, nor are all of the tools installed in the same way, nor do they all use the same format for accessing the AWS credentials.

The following steps show how I install and configure the AWS command line tools provided by Amazon when I don’t use the packages provided by Ubuntu.

Amazon just announced two related features for getting super-fast, consistent performance with EBS volumes: (1) Provisioned IOPS EBS volumes, and (2) EBS-Optimized Instances.

Starting new instances and EBS volumes with these features is fine, but what if you already have some running instances you’d like to upgrade for faster and more consistent disk performance?

Given the two AWS features, there are two separate powers that need to be engaged to take full advantage:

1. Convert the EBS volume(s) from standard EBS volumes into new Provisioned IOPS EBS volume(s).

2. Convert the standard EC2 instance into an EBS-Optimized instance.

This article demonstrates how to take an existing EBS boot instance that is already running and convert it to use both of these two EBS performance features. Note that there will be some increased costs; please study Amazon’s published pricing before attempting.

Did you know that Amazon includes status messages about the health of availability zones in the output of the ec2-describe-availability-zones command, the associated API call, and the AWS console?

Right now, Amazon is restoring power to a “large number of instances” in one availability zone in the us-east-1 region due to “electrical storms in the area”.

Since the names used for specific availability zones differ between AWS accounts, Amazon can’t just say that the affected zone is us-east-1c as it might be us-east-1e in another account.

During this outage, you can find out what the name of the affected availability zone is in your AWS account by running this command (installation instructions):

See also: Installing AWS Command Line Tools from Amazon Downloads

Here are the steps for installing the AWS command line tools that are currently available as Ubuntu packages. These include:

• EC2 API tools
• EC2 AMI tools
• IAM - Identity and Access Management
• RDS - Relational Database Service
• CloudWatch
• Auto Scaling
• ElastiCache

Starting with Ubuntu 12.04 LTS Precise, these are also available:

• CloudFormation
• ELB - Elastic Load Balancer

Install Packages

I will be attending the Ubuntu Developer Summit (UDS) next week in Oakland, CA.  This event brings people from around the world together in one place every six months to discuss and plan for the next release of Ubuntu.  The May 2012 UDS is for Ubuntu-Q which will eventually be named and become Ubuntu 12.10 when it is released in October (2012-10).

The ssh protocol uses two different keys to keep you secure:

1. The user ssh key is the one we normally think of. This authenticates us to the remote host, proving that we are who we say we are and allowing us to log in.

2. The ssh host key gets less attention, but is also important. This authenticates the remote host to our local computer and proves that the ssh session is encrypted so that nobody can be listening in.

Every time you see a prompt like the following, ssh is checking the host key and asking you to make sure that your session is going to be encrypted securely.

The authenticity of host 'ec2-...' can't be established.
ECDSA key fingerprint is ca:79:72:ea:23:94:5e:f5:f0:b8:c0:5a:17:8c:6f:a8.
Are you sure you want to continue connecting (yes/no)? 

If you answer “yes” without verifying that the remote ssh host key fingerprint is the same, then you are basically saying:

I don’t need this ssh session encrypted. It’s fine for any man-in-the-middle to intercept the communication.

Ouch! (But a lot of people do this.)

Amazon Web Services is such a huge, complex service with so many products and features that sometimes very simple but powerful features fall through the cracks when you’re reading the extensive documentation.

One of these features, which has been around for a very long time, is the ability to use AWS to seed (serve) downloadable files using the BitTorrentâ„¢ protocol. You don’t need to run EC2 instances and set up software. In fact, you don’t need to do anything except upload your files to S3 and make them publicly available.

Any file available for normal HTTP download in S3 is also available for download through a torrent. All you need to do is append the string ?torrent to the end of the URL and Amazon S3 takes care of the rest.

Steps

Let’s walk through uploading a file to S3 and accessing it with a torrent client using Ubuntu as our local system. This approach uses s3cmd to upload the file to S3, but any other S3 software can get the job done, too.

There are a number of CloudCamp events coming up in cities around the world. These are free events, organized around the various concepts, technologies, and services that fall under the “cloud” term.

There’s always some discussion about my favorite topic, Amazon AWS and EC2, but there are sure to be experts and beginners for every other cloud-related flavor as well. You can attend presentations, join in discussions, or hang out in the hallway and make connections with local folks who are interested in the same things you are.

CloudCamp follows somewhat of an unconference format, though the couple I’ve been to in LA tended to have more pre-planned elements than, say, a BarCamp. Glancing through the schedules, it looks like each city also has their own twist and personality for CloudCamp.

Here are two upcoming CloudCamps that are of particular interest to me:

A few hours ago, Amazon AWS announced that all EC2 instance types can now run 64-bit AMIs.

Though t1.micro, m1.small, and c1.medium will continue to also support 32-bit AMIs, it is my opinion that there is virtually no reason to use 32-bit instances on EC2 any more.

This is fantastic news!

The source for ec2-conssitent-snapshot has historically been available here:

ec2-consistent-snapshot on Launchpad.net using Bazaar

For your convenience, it is now also available here:

ec2-consistent-snapshot on GitHub using Git

You are welcome to fork ec2-consistent snapshot under the liberal terms of the Apache License, Version 2.0.

I welcome patch submissions, especially if:

EBS boot vs. instance-store

If you are just getting started with Amazon EC2, then use EBS boot instances and stop reading this article. Forget that you ever heard about instance-store and accept my apology that I just mentioned it. Once you are completely comfortable with using EBS boot instances on EC2, you may (or may not) want to come back here and read why you made a good decision.

EC2 experts may find that there are specific cases, few and far between, where instance-store might make sense, but they don’t attempt to use instance-store without understanding and accounting for all the serious drawbacks and dangers that go with making this choice. For example, experts using instance-store don’t mind losing all of the data on the instance as they have designed the system so that the data is stored elsewhere and so that a new instance can easily and automatically be rebuilt from scratch.

One of the challenges for beginners is that many of the benefits of EBS boot don’t necessarily seem like something you’ll need to use right away. Then they get down the road and into situations where they realize that they would have been much better off if they had gone with EBS boot in the first place and may find it takes some work to make the transition.

Big benefits of EBS boot instances

Here are some of the reasons I use and recommend EBS boot instances. None of these benefits are available with instance-store, so even a single one of these can be an overriding factor for choosing EBS boot.

A serverfault poster had a problem that I thought was a cool challenge. I had so much fun coming up with this answer, I figured I’d share it here as it demonstrates a few handy features of EC2.

Challenge

The basic need is to get the public ssh key from a keypair that exists inside of EC2. You don’t have access to the private key at the moment (but somebody else does or you will at a different location).

The AWS console and EC2 API do not let you ask for the public ssh key associated with a keypair. However, EC2 does pass the public ssh key to a new EC2 instance when you run it with a specific keypair.

The problem is that we don’t currently have the private key, so we can’t log in to the EC2 instance to get the public key. (Besides, if we did have the private key, we could extract the public key from it directly.)

Solution

I proposed creating a user-data script that sends the public ssh key to the EC2 instance console output. You can retrieve the console output without logging in to the EC2 instance.

Do you want to run short jobs on Amazon EC2 on a recurring schedule, but don’t want to pay for an instance running all the time?

Would you like to do this using standard Amazon AWS services without needing an external server to run and terminate the instance?

Amazon EC2 Auto Scaling is normally used to keep a reasonable number of instances running to handle measured or expected load (e.g., web site traffic, queue processing).

In this article I walk through the steps to create an Auto Scaling configuration that runs an instance on a recurring schedule (e.g., four times a day) starting up a pre-defined task and letting that instance shut itself down when it is finished. We tweak the Auto Scaling group so that this uses the minimum cost in instance run time, even though we may not be able to predict in advance exactly how long it will take to complete the job.

Here’s a high level overview for folks familiar with Auto Scaling: