Capistrano times out when deploying using Amazon RDS - capistrano

Question

I cannot seem to get Capistrano to play nicely with AmazonRDS. I've looked all over the place for any info on setting this up correctly, but haven't found any. Right now, when I cap deploy, the process times out.
This is my deploy.rb:
set :deploy_to, "/opt/bitnami/apps/annarbortshirtcompany.com/cms/"
set :scm, :git
set :repository, "ssh://user#ec2-repository.compute-1.amazonaws.com/~/repo/cms.git"
set :deploy_via, :remote_cache
set :user, "user"
ssh_options[:keys] = [File.join(ENV["HOME"], "EC2", "admin.pem")]
ssh_options[:forward_agent] = true
set :branch, "master"
set :use_sudo, true
set :location, "ec2-webserver.compute-1.amazonaws.com"
role :web, location
role :app, location
role :db, "cmsinstance.c7r8frl6npxn.us-east-1.rds.amazonaws.com", :primary => true
# If you are using Passenger mod_rails uncomment this:
namespace :deploy do
task :start do ; end
task :stop do ; end
task :restart, :roles => :app, :except => { :no_release => true } do
run "#{try_sudo} touch #{File.join(current_path,'tmp','restart.txt')}"
end
end
The username for the RDS database instance differs from the SSH username set here, but is defined in my database.yml. I figure that this is probably not being read by capistrano, but have no idea how to make that happen.
When I "cap deploy":
ubuntu#ubuntu-VirtualBox:~/RailsApps/cms$ cap deploy
* executing `deploy'
* executing `deploy:update'
** transaction: start
* executing `deploy:update_code'
updating the cached checkout on all servers
executing locally: "git ls-remote ssh://user#ec2-repository.compute-1.amazonaws.com/~/repo/cms.git master"
command finished in 1590ms
* executing "if [ -d /app-directory/shared/cached-copy ]; then cd /app-directory/shared/cached-copy && git fetch -q origin && git fetch --tags -q origin && git reset -q --hard ffc4ec7762566f801c4a9140aa3980dc71e3d06f && git clean -q -d -x -f; else git clone -q ssh://user#ec2-repository.amazonaws.com/~/repo/cms.git /app-directory/shared/cached-copy && cd /app-directory/shared/cached-copy && git checkout -q -b deploy ffc4ec7762566f801c4a9140aa3980dc71e3d06f; fi"
servers: ["ec2-webserver.compute-1.amazonaws.com", "dbinstance.us-east1.rds.amazonaws.com"]
*** [deploy:update_code] rolling back
* executing "rm -rf /app-directory/releases/20110607161612; true"
servers: ["ec2-webserver.compute-1.amazonaws.com", "dbinstance.us-east1.rds.amazonaws.com"]
** [deploy:update_code] exception while rolling back: Capistrano::ConnectionError, connection failed for: dbinstance.us-east1.rds.amazonaws.com (Errno::ETIMEDOUT: Connection timed out - connect(2))
connection failed for: dbinstance.us-east1.rds.amazonaws.com (Errno::ETIMEDOUT: Connection timed out - connect(2))
Why would it want to "update the cached checkout on all servers"? The DB server shouldn't even be needed at this point. I am stumped at how to fix this. Hopefully someone can point me in the right direction!

Answer 1

I had this exactly problem and struggled with it for what I'm embarrassed to say was a good 5 or 6 hours. In the end, when I realized what the problem was I felt like smacking myself because I knew this once but had forgotten it. Here's the crux of the problem, starting with this part of deploy.rb:
set :location, "ec2-webserver.compute-1.amazonaws.com"
role :web, location
role :app, location
role :db, "cmsinstance.c7r8frl6npxn.us-east-1.rds.amazonaws.com", :primary => true
When you define the machine roles for Capistrano, you're not actually identifying which machines will play a particular role...rather, you're identifying on which machines the Capistrano code will run when applying a deployment recipe for a role. So, when you define the :db role, you want to point to your EC2 instance, not the RDS instance. You can't ssh into the RDS machine, so it's impossible for Capistrano to run a recipe there. Instead, point :db to the same machine as you're pointing :web and :app, i.e.
set :location, "ec2-webserver.compute-1.amazonaws.com"
role :web, location
role :app, location
role :db, location, :primary => true
How does the RDS machine then have any involvement? Well, it's the database.yml file that dictates which machine is actually running the RDBMS where the SQL needs to be executed. You just need to be sure you're setting the host: value for the target database, e.g.:
production:
adapter: mysql2
encoding: utf8
reconnect: false
database: <your_db>_production
pool: 5
username: <username>
password: <password>
host: cmsinstance.c7r8frl6npxn.us-east-1.rds.amazonaws.com
Make sense?
I hope this save someone else the frustration I experienced.
David