Getting the most out of Chef with Scalarium and vagrant

Wednesday, March 9. 2011
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Ever since I started playing around with Unix ~13 years ago, I've been a fan of automating things. What started out as writing little (maybe pointless) shell scripts slowly but surely morphed into infrastructure automation today.

As for my, or maybe anyone's, motivation to do these things, I see three main factors:

  • I'm easily bored — because repeating things is dull.
  • I'm easily distracted (when I'm bored).
  • I'm German: Of course we strive for perfection and excellence. ;-)

Being on Unix (or Linux) it's fairly simple to automate things — add some script-fu to bash or csh (or even better zsh) and off you go wrapping things into a small shell script! Then execute again and again!

Before we decided to moved to AWS (and RightScale) in late 2009 we had half a rack of servers (in a Peer1's POP in NYC) and never did any or much infrastructure automation. We had an image and a set of commands to get a server up and running, but it was far from two mouse-clicks today.

At the time, I had read about cfengine a couple of times, but datacenter-grade infrastructure management along with a rather steep learning wall (at that time anyway) seemed overkill. Add to that, that there is not a lot of time for research Fridays when you work in a small company.

Moving to AWS and RightScale required us to write lots of small shell scripts using bash and Ruby. When we moved from RightScale to Scalarium in late 2010, we went from shell scripts to Chef.

Using Chef meant that we created so-called recipes which are used to bootstrap our servers. Recipes are little Ruby scripts which live in a cookbook — open source projects are sometimes so creative. Before this move I had very little, or next to no, experience with Chef, and Chef being Ruby didn't exactly make me want to try it either.

So what exactly is Chef?

A Chef recipe is a tiny bit of Ruby code — essentially a high(er)-level wrapper around calls such as installing certain packages, creating and parsing configuration files and many other things.

Chef offers a robust abstraction about everything you can do with shell and with a little effort it's also possible to write recipes which run on multiple OS'. Supported are Ubuntu, CentOS, FreeBSD and others. For an intro to Chef see the slides of a talk I gave a couple weeks ago; I briefly blogged about it too.

Our Chef recipes currently include things like installing and configuring PHP (from source and through a launchpad repository), nginx, MySQL, CouchDB, haproxy and many other things. The list was literally growing every day for the first few weeks.


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Thoughts on RightScale

Tuesday, October 20. 2009
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RightScale provides all kinds of things — from a pre-configured MySQL master-slave setup (with automatic EBS/s3 backups), to a full LAMP stack, Rails app servers, virtually all kinds of other pre-configured server templates to a nifty auto-scaling feature.

We decided to leverage RightScale when we planned our move to AWS a couple months ago in order to not have to build everything ourselves. I've been writing this blog entry for the past five weeks and here are some observations, thoughts and tips.

RightScale

First off, whatever you think, and do, or have done so far, let me assure you, there's always a RightScale way of doing things. For (maybe) general sanity (and definitely your own), I suggest you don't do it their way — always.

One example for the RightScale way is, that all the so-called RightScripts will attempt to start services on reboot for you, instead of registering them with the init system (e.g., on Ubuntu, update-rc.d foo defaults) when they are set up.

You may argue that RightScale's attempt will provide you with a maybe more detailed protocol of what happened during the boot sequence, but at the same time it provides more potential for errors and introduces another layer around what the operating system provides, and what generally works pretty well already.

PHP and RightScale

RightScale's sales team knows how to charm people, and when I say charm, I do not mean scam (just for clarity)! :-)

The demos are very impressive and the client show cases not any less. Where they really need to excel though are PHP-related demos because not everyone in the world runs Ruby on Rails yet. No, really — there's still us PHP people and also folks who run Python, Java and so on.

Coming from the sales pitch, I felt disappointed a little because a standard PHP setup on RightScale is as standard as you would think three years ago. mod_php, Apache2 and so on. The configuration itself is a downer as well, a lot of unnecessary settings and generally not so speedy choices. Then remember that neither CentOS nor Ubuntu are exactly up to date on packages and add another constraint to the mix — Ubuntu is on 8.04 which is one and half years in the past as I write this entry.

And even though I can relate to RighScale's position — in terms of that supporting customers with all kinds of different software is a burden and messy to say the least — I am also not a fan.

Scaling up

The largest advantage when you select a service provider such as RightScale is, that they turn raw EC2 instances into usable servers out of the box. So far example setting up a lamp stack yourself requires time, while it's still a trivial task for many. With RightScale, it's a matter of a couple clicks — select image, start, provide input variables and done.

Aside from enhanced AMIs RightScale's advantage is auto-scaling. Auto-scaling has been done a couple times before. There are more than one service provider which leverages EC2 and provides scalability on top. Then take a look at Scalr, which is open source, and then recently Amazon themselves added their own Elastic Load Balancer.

In general, I think auto-scaling is something everyone gets, and wants, but of course it's not that dead simple to implement. And especially when you move to a new platform, it's a perfect trade off to sacrifice a flexibility and money for a warm and fuzzy "works out of the box" feeling.


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AddressLimitExceeded: Too many addresses allocated

Tuesday, October 13. 2009
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I got this error message tonight when I tried to allocate another EIP from within RightScale's dashboard. So it turns out there is a maximum of 5 (E)IPs on all AWS accounts, but there's a contact form to request more. Meh.

I wish AWS would make this part slightly easier, e.g. by announcing a customer's own IP space.

CouchDB on Ubuntu on AWS

Friday, August 28. 2009
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Here's a little HowTo on how to setup CouchDB on an AWS EC2 instance. But outside of AWS (and EC2), this setup works on any other Ubuntu server, and I suppose Debian as well.

Getting started

The following steps are a rough draft, or a sketch on how to get started. I suggest that you familiarize yourself with what all of these things do. If you want to skip on the reading and just get started, this should work anyway.

  • you (obviously) need an AWS account (and log into the AWS console).
  • you need a custom security group (make sure to open up for http traffic)
security_group_001

security_group_002

  • create an EBS volume (Take a deep breath and think about the size of the volume. Keep in mind that you don't want to run into space issues right away and that allocated storage (even idle) costs you money (e.g. 400 GB =~ 40 USD (per month), excluding the i/o).)
  • create a keypair (It'll prompt you to download a foobar.pem, I placed mine on my local machine in ~/.ssh/ and ran chmod 400 on it.)
  • get an elastic IP
  • start the instance
    • select an AMI (I selected alestic's 64bit server Ubuntu 9.04 AMI.)
    • assign your own security group AND the defaults one
    • select your keypair

Woo! We made it that far.

The instance should boot and once this is done (green indicates all went well), we want to associate the previously created EBS volume and the elastic IP to said instance.

Once these steps are complete, go on the instance screen, click on your running instance and then click on "Connect". It'll show you the ssh command to connect to your instance -- it should be similar to this:

ssh -i .ssh/foobar.pem [email protected]

The W-X-Y-Z part is most likely replaced with your elastic IP.

This process is not very automated yet, but at least you have an instance up and running. The next step is to try to login and see if the EBS was attached — if all went well, you should have /mnt.


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