abstraction

Excellent talk from Pat Helland, “Immutability Changes Everything” :

via igrigorik's twitter

this google+ hangout, combined with this post and all it's links, provides plenty of good discussion and ideas for Chef.

Unfortunately I forget where I found this link - Hacker News? The Edge Newsletter? I dunno, but it's a pretty interesting one -

A debate between an MIT professor, Erik Brynjolfsson, and an Economist, Tyler Cowen, about the the role of technology in driving economic growth. My views side with the MIT professor, as does most of the audience in the debate.

I won't repeat any of the arguments made in the debate, but what I will add is that the unequal distribution of wealth we see around today is not a symptom of lack of technological growth, it is purely down to good old fashioned political manipulation and deep rooted traditions of cronyism, a tradition thousands of years old.

Technology on the other hand: absolutely it's what will drive the economy, but even that view completely misses the big picture, which is the Medium itself, The Universal Network. I believe we have created a whole new dimension, an evolutionary mathematical abstracted form of biology. This is the beginning of History, Year Zero.

One hundred years from now, or two thousand - people will be able to look back in time and know with a rich level of detail what our life is like now. Thousands, upon millions of instances of video and audio, images, writings, geo locations, online trails, all readily accessible, interlinked and searchable. This level of detail will only increase, as we start recording every aspect of life.

With such archives of data, I can easily imagine the kids of 2123 being able to walk through and interact with a virtual London in the swinging 2020′s, or San Francisco's roaring 2030′s. Whereas, for future generations, any time predating the late 1990′s will essentially be a static foreign place in comparison. We have created time-travel - we just don't know it yet.

This Network has already achieved a basic level of independence from humanity - where now it is possible for a Something to exist outwith a single containing computer system using techniques like redundancy and geographic load-balancing. I don't mean to imply there is any intelligence there, but there is a level of resilience we've never seen in nature before. To give a more concrete example, I'm referring to something like you as a user interacting with the amazon website to purchase something, meanwhile the power goes out in the datacentre hosting the server your browser was communicating with, and, if engineered correctly, your interaction could continue, picked up by a secondary datacentre with no loss of data, nor interruption of service. This isn't exactly life as we know it, but if you squint your eyes just a little, its not too hard to see an analogy to biological cell life.

Over the next few years, Society's experience of reality is going to go through the biggest change in history, as our physical world merges completely with this new virtual world of realtime interconnected information and communication, completely warping our sense of time and geography.

The iPhone was stage one, Google Glasses or something very similar will be stage two, and its right around the corner.

This is an excellent talk about the interaction between the various layers of memory abstraction from the a machine's physical memory down through the Hypervisor's view, to the Guest OS's and down into the JVM:

// found via Marakana //

I finished reading James Gleick's The Information tonite - so good!

Really, the central character is Claude Shannon, who I'm ashamed to admit I didn't previously know much about. Had a quick search when i finished it and found this decent little 30 min documentary which gives a good overview -

found via Boing Boing, excellent 20min short from 1923 -

I've been reading through ThoughtWorks' latest ‘technology radar‘ which led me to look up Vagrant, one of the tools they list as worth exploring.

Vagrant is a framework for building and deploying Virtual Machine environments, using Oracle VirtualBox for the actual VMs and utilizing Chef for configuration management.

Watching through this intro video:

http://vimeo.com/9976342

i was quite intrigued as it is very similar to what i was looking to achieve earlier when i was experimenting with installing Xen and configuring with Puppet.

So here's what I experienced during the setup of Vagrant on my Macbook - I decided to start with a simple Chef install to familiarise myself with Chef itself and it's own requirements CouchDB, RabbitMQ and Solr, mostly by following these instructions -

-CHEF INSTALL-

sudo gem install chef
sudo gem install ohai

Chef uses couchDB as it's datastore, so we need to install it using the instructions here

brew install couchdb

The instructions I list above also contains steps to install a couchDB user and set it up as a daemon. They didn't work for me, and after 30mins of troubleshooting, i gave up and went with the simpler option of running it under my own user - in production this will be running on a Linux server rather than my Macbook, so it seemed fair enough -

cp /usr/local/Cellar/couchdb/1.1.0/Library/LaunchDaemons/org.apache.couchdb.plist ~/Library/LaunchAgents/

launchctl load -w ~/Library/LaunchAgents/org.apache.couchdb.plist

Check its running okay by going to
http://127.0.0.1:5984/

which should provide something akin to :
{“couchdb”:”Welcome”,”version”:”1.1.0″}

- INSTALL RABBITMQ -

brew install rabbitmq
/usr/local/sbin/rabbitmq-server -detached

sudo rabbitmqctl add_vhost /chef
sudo rabbitmqctl add_user chef testing
sudo rabbitmqctl set_permissions -p /chef chef “.*” “.*” “.*”

Ok, Gettin' back to my mission, break out the whipped cream and the cherries, then I go through all the fly positions - oh, wrong mission!

Ok..

brew install gecode
brew install solr

sudo gem install chef-server chef-server-api chef-server chef-solr
sudo gem install chef-server-webui
sudo chef-solr-installer

Setup a conf file -
sudo mkdir /etc/chef
sudo vi /etc/chef/server.rb - paste in the example from:

http://wiki.opscode.com/display/chef/Manual+Chef+Server+Configuration - making the appropriate changes for your FQDN

At this point, the above instructions ask you to start the indexer however the instructions haven't been updated to reflect changes to Chef version 0.10.2 in which chef-solr-indexer has been replaced with chef-expander

So, instead of running:
sudo chef-solr-indexer

you instead need to run:
sudo chef-expander -n1 -d

Next i tried
sudo chef-solr

which ran into
“`configure_chef': uninitialized constant Chef::Application::SocketError (NameError)”

i had to create an /etc/chef/solr.rb file and simply add this to the file:

require ‘socket'

startup now worked -
if you want to daemonize it, use:

sudo chef-solr -d

Next start Chef Server with:
sudo chef-server -N -e production -d

and finally:
sudo chef-server-webui -p 4040 -e production

Now you should be up and running - you need to configure the command client ‘Knife' follwing the instructions here - under the section ‘Configure the Command Line Client‘

mkdir -p ~/.chef
sudo cp /etc/chef/validation.pem /etc/chef/webui.pem ~/.chef
sudo chown -R $USER ~/.chef

knife configure -i

(follow the instructions at the link - you only need to change the location of the two pem files you copied above)

Ok, so hopefully you're at the same place as me with this all working at least as far as being able to log into CouchDB, and verifying that Chef/Knife are both working.

- VAGRANT SETUP -

Now, onward with the original task of Vagrant setup…
Have a read over the getting started guide:

Install VirtualBox - download from http://www.virtualbox.org/wiki/Downloads

Run the installer, which should all work quite easily. Next..

gem install vagrant

mkdir vagrant_guide
cd vagrant_guide/
vagrant init

this creates the base Vagrantfile, which the documentation compares to a Makefile, basically a reference file for the project to work with.

Setup our first VM -
vagrant box add lucid32 http://files.vagrantup.com/lucid32.box

This is downloaded and saved in ~/.vagrant.d/boxes/

edit the Vagrantfile which was created and change the “box” entry to be “lucid32″, the name of the file we just saved.

Bring it online with:
vagrant up

then ssh into with
vargrant ssh

Ace, that worked quite easily. After a little digging around, I logged out and tore the machine down again with
vagrant destroy

- TYING IT ALL TOGETHER -
Now we need to connect our Vagrant install with our Chef server

First, clone the Chef repository with:
git clone git://github.com/opscode/chef-repo.git

add this dir to your ~/.chef/knife.rb file
i.e
cookbook_path ["/Users/thorstensideboard/chef-repo/cookbooks"]

Download the Vagrant cookbook they use in their examples -

wget http://files.vagrantup.com/getting_started/cookbooks.tar.gz
tar xzvf cookbooks.tar.gz
mv cookbooks/* chef-repo/cookbooks/

Add it to our Chef server using Knife:
knife cookbook upload -a
(knife uses the cookbook_path we setup above)

If you browse to your localhost at
http://sbd-ioda.local:4040/cookbooks/
you should see the three new cookbooks which have been added.

Now to edit Vagrantfile and add your Chef details:

Vagrant::Config.run do |config|

config.vm.box = "lucid32"

config.vm.provision :chef_client do |chef|

chef.chef_server_url = "http://SBD-IODA.local:4000"
chef.validation_key_path = "/Users/thorsten/.chef/validation.pem"
chef.add_recipe("vagrant_main")
chef.add_recipe("apt")
chef.add_recipe("apache2")

end
end


I tried to load this up with
vagrant up
however received:

“[default] [Fri, 05 Aug 2011 09:27:07 -0700] INFO: *** Chef 0.10.2 ***
: stdout
[default] [Fri, 05 Aug 2011 09:27:07 -0700] INFO: Client key /etc/chef/client.pem is not present - registering
: stdout
[default] [Fri, 05 Aug 2011 09:27:28 -0700] FATAL: Stacktrace dumped to /srv/chef/file_store/chef-stacktrace.out
: stdout
[default] [Fri, 05 Aug 2011 09:27:28 -0700] FATAL: SocketError: Error connecting to http://SBD-IODA.local:4000/clients - getaddrinfo: Name or service not known”

I figured this was a networking issue, and yeah, within the VM it has no idea of my Macbook's local hostname, which i fixed by editing its /etc/hosts file and manually adding it.

Upon issuing a
vagrant reload, boom! you can see the Vagrant host following the recipes and loading up a bunch of things including apache2

However at this point, you can still only access it's webserver from within the VM, so in order to access it from our own desktop browser, we can add the following line to the Vagrantfile:
config.vm.forward_port(“web”, 80, 8080)

After another reload, you should now be able to connect to localhost:8080 and access your new VM's apache host.

In order to use this setup in any sort of dev environment will still need a good deal more work, but for the moment, this should be enough to get you up and running and able to explore both Vagrant and Chef.

I keep coming across mentions of node.js, but wasn't sure what it was. This morning I've been watching some tutorials and reading up a little, and from what I understand it's basically a network server framework built on top of Google's V8 JavaScript engine, really an abstraction for socket programming. It's main advantage is speed and scalability, due to it being based on an event driven I/O model, rather than threaded, like most other languages or frameworks.

This video from node's creator, Ryan Dahl is a pretty funny and very informative introductory video. I'd recommend programming along with watching it:

Here's some further links:
http://nodejs.org/docs/v0.4.8/api/synopsis.html
http://howtonode.org/

This podcast is also a good source of information:
http://herdingcode.com/?p=299

First draft of my Record Store Bot is live over on Github - basically tying a Chatbot::Eliza style interface to Last.fm web services for an interactive (hopefully amusing) music recommendation bot.

Works surprisingly well - although only has one method at the moment..