It's a busy week for JBossians. We're all (well, almost) in Boston attending JUDCon and JBoss World/Red Hat Summit. StormGrind was represented by Bob at JUDCon. We had two presentations: Cooling Tower/CirrAS and BoxGrinder. If you hadn't chance to attend JUDCon – we uploaded slides especially for you!
In case you missed our previous announcement: today we'll talk about two of our projects: BoxGrinder (Bob McWhirter) and CoolingTower (Michael Neale) at Red Hat's Open Source Cloud Computing Forum. It's a free online event. Hurry up and register here!
Full agenda is posted here. The Cloud Forum starts on 9:30 AM EST.
You can read more about BoxGrinder and CoolingTower projects on our wiki.
I you were unable to attend the Forum you can listen to all talks from the archive for Red Hat's 2nd Open Source Cloud Computing Forum.
Inspired by the good folks at Rackspace (specifically, this post), I realised how important it was to have a easily programmable DNS api for cloud applications and services.
Why do I need to care about DNS ?
Well, its all very well deploying your fantastic app to a fantastic elastic cluster, but its not so fun when it has urls like
(I hope I haven't offended anyone by using those addresses - there was one time Van Halen put a serial number on the back of an album that happened to be someones phone number, so crazed fans called the number, over and over, until Van Halen was sued over it. But I digress). So to avoid being sued due to over zealous Van Halen fans, you need to have a naming service: DNS. The fabric of the internet, full of quaint terms like "bailiwick" (I wish I wasn't making this up). For single apps, you can use either your own DNS server(s), or use a pay for service etc (there are many options of course). Running your own DNS is nice, it gives you flexibility to run many apps under one domain (using subdomains for specific apps), use it to "move" apps around whenever you need (which is pretty common in clouds - servers can come and go, change data centres, change IPs as you bring up a new one etc).
A simple API
Wouldn't it be nice to have some near API to make it as simple as:
curl -d subdomain=applicationName&address=126.96.36.199 http://coolingtower/api/naming/domains/samplezone.org curl -d subdomain=applicationName&address=somewhere.com http://coolingtower/api/naming/domains/samplezone.org
Well you would be in luck! (It is a nice rule of thumb that a RESTful interface can be driven from the command line - the above using the excellent curl tool - you can use anything of course). However, DNS is full of traps for young players, and really, what we want is to be a big Map<String, IP> in the sky, magically guiding browsers to the right server.
Where and when would I use this?
Mainly for the entry points that end users will see in their browser- but it can also be useful for internal resources like databases, and other services that your applications consume (to avoid binding to IPs directly). For example, imagine you have your own cloud service, you register name for the top level domain: stormgrind.com. With a DNS service you can have:
http://demo.stormgrind.com http://db1.stormgrind.com http://www.stormgrind.com
...and so on, you get the idea.
A RESTful API for DNS management
CoolingTower has a programmatic (RESTful) interface to manage DNS mappings, and also an (optional) authoritative DNS server (if you don't have one already). DNS data is stored in standard "zone files". It will validate and store the changes in zone files - and those changes can be propagated to the DNS servers. If you use the EagleDNS service it will instantly pick up the changes and apply them - applying sensible defaults, updating serial numbers, setting short time to live values (so changes are applied quickly) - all are done automatically to keep things easy and less error prone. There is much more to the RESTful api, and it is being documented.
More info and some links
Red Hat is hosting its 2nd Open Source Cloud Computing Forum on 10 February. This is a free, online event, so prepare some time on 10th February. We'll have two sessions there:
- BoxGrinder on 10:00 AM, 10 Feb 2010 - Bob McWhirter
- Cooling Tower on 3:30 AM, 10 Feb 2010 - Michael Neale
We're happy to meet you there!