Chronicling my experiences with ruby on rails, web application development/management.

Friday, December 5, 2008

Transferring an existing app to a new server

Let the good times roll gents. Rick Okasik and the cars once sang that song about this exact moment in time. The day I transferred my existing ruby on rails site from a shared host to slicehost.


Preamble - Reasons why, etc...


My shared hosting account at a2 has come to an end. They have been having a couple of days worth of outages here and there. Nothing too bad, usual disk failure kinds of stuff, but what really got my goat was this. A bug in cpanel that didn't allow the mongrel server to restart. So my site would be down for an eon, because they restarted the server or apache or something (never got straight answers). Now i'm a patient guy, but in terms of my website as a business, they were messing with my livelyhood. Good intentions or not, it sucked for that reason.


So the time has come to grow up and move to slicehost. I've tried Linode but i prefer slicehost. Both really offer the same principle offerings and are strictly/typically linux based servers, so i liked these two. But for some reason, slicehost resonated more with me. Just a thing i have, no fault of anyones.


Steps involved in transferring an existing app to a new server


I'll be chronicling my journey through transferring a rails app from a shared host to a VPS like slicehost. Here are the steps I took to move the server:

  1. Backed up MySQL database on old server

  2. Ftp'd backup db to new server

  3. Copied app code to new server

  4. Imported DB onto new server

  5. Fixed app settings to let it run properly, such as action mailer, etc.

  6. Updated DNS records to reflect the switch.


For the record, i already have a working passanger/mail system/rails stack on slicehost. I will chronicle what I needed to do to get this to work. However, your mileage may vary and if you screw up anything, even because of my instructions, i'm sorry, but that's on you and i won't and can't be held responsible. You've been warned.


Good, got that crap out of the way, on with the show.


Export Mysql database from old server


I followed this Slicehost article on exporting and importing db's. It was pretty easy so far.


Zip code on OLD server


As i'm using the command line for all/most of this transfer, a great resource for zipping files was About.com. Although not as sexy to use, it had all i needed. I used the following commands:

zip -r app_new app -x \*.log

Notice the -x which will exclude your stupidly huge log files. I need to find a better way to manage them.

By the way i went from 40mb zip file with logs to 10.5mb zip file. need i say more

FTP code and .sql file to New Server


No explanation really needed here. I used ftp from old server to my desktop and then i used sftp onto new server at slicehost. Your mileage may vary, but you get the idea.


Unzip code into new /var/sites/ directory


I unzipped the code into a web-applicaton chmod'd directory.
unzip app.zip


Import DB.sql file into the NEW Server


The Slicehost article on exporting and importing db's again came in handy here. So easy, so good.


Setup your new DB user


I ended up creating a new user, just to be safe. Probably no need to do this, as you can keep the same one from your old server, but just in case. I just followed this Slicehost article on creating Mysql users. Grant All privleges, as he shows in the article.


install all your outstanding gems


Since i forgot which gems i need, and I am not ready to upgrade this app to 2.2.2 yet, as it's in rails 2.0.2, I need to go to the old server, and pull off all the gems i used, and reinstall them on the NEW server. Once this is done, we can setup the config files for actionmailer and the db itself.

Well it looks like it's the old rmagick gem that was the troublsome one. Thanks to enrailed.net for helping me out with this one. It's weird to me how i followed the same steps using aptitude and I got an error, but if i use apt-get, i was fine... whatever eh! Oh and gem install rails -v 2.0.2 just hung there, so i said screw it, and i'm going to go with the one i have on there 2.1.2.

Lastly for all UBUNTU Hardy users that don't know.... update your ruby gems. the POS that is shipped with that ubuntu version will disappoint you, if it hasn't already. Thanks to Mike's post here at a fresh cup blog you'll find out how more. Simply put, just run
sudo gem install rubygems-update
sudo update_rubygems



Update Config and database files


so you'll need to update anything in your config/environment.rb file that was server specific, such as actionmailer settings. Also, make sure your config/database.yml file reflects your NEW database.


Update your server settings


I, like most of the free rails world, are now using passanger to serve our app. If you aren't, run, don't walk, to the nearest passanger downloading station and fricking do it! Mongrel's time has passed, much like zed shaw's rants. It meets my needs, that is for sure.

I added the following code to passanger:

ServerName sitename.com
ServerAlias www.sitename.com
DocumentRoot /var/rails/sitename/public



Since i have two other sites on my slice, i need to make sure that the NameVirtualHost *.80 is only added to the "first" site or in other words, only once.

The best passanger, slice from scratch tutorial is Part One and Two of sys admin chronicles.

Change your DNS records on your slice and with your Registrar


You'll need to change where your DNS is pointed, i.e., from the OLD server to the NEW one. Slicehost makes that part easy with their DNS manager. For the registrar part, you need to go to the registrar of record, in order to point it to the new settings. I change the registrar's record first, then i change mine on slicehost. But again, that's what i've done.


Restart the App and you are done


I think that is it friends. You should have the same app as you had before working on a new server. This wasn't rocket-science but it was a good list of 'things you need to do' when converting over to a new server.


To do...


I'll post how i got a multi-website postfix configuration going on my slice. I've yet to find an easy tutorial that works... but i'm looking. Thanks everyone. The good times are rolling again.

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