Keep getting 504 Gateway Time-out after deploying

问题:

I used the rubber gem to deploy my application on ec2. I followed the instructions here: http://ramenlab.wordpress.com/2011/06/24/deploying-your-rails-app-to-aws-ec2-using-rubber/.
The process seems to finish successfully but when I try to use the app I keep getting 504 gateway time-out. Why is this happening and how do I fix it?

回答1:

Answer from Matthew Conway (reposted below): https://groups.google.com/forum/?fromgroups#!searchin/rubber-ec2/504/rubber-ec2/AtEoOf-T9M0/zgda0Fo1qeIJ

Note: Even with this code you need to do something like:

> cap deploy:update

> FILTER=app01,app02 cap deploy:restart

> FILTER=app03,app04 cap deploy:restart

---

I assume this is a rails application? The rails stack is notoriously slow to load up, so this delay in load time is probably what you are seeing. Passenger was supposed to make this better with the zero downtime feature v3, but they seemed to have reneged on that and are only going to be offering it as part of some undefined paid version at some undefined point n the future.

What I do is have multiple app server instances and restart them serially so that I can continue to serve traffic on one, while the others are restarting. Doesn't work with a single instance, but most production setups need multiple instances for redundancy/reliability anyway. This isn't currently part of rubber, but I have it deploy scripts setup for my app and will merge it in at some point - my config looks something like the below.

Matt

rubber-passenger.yml:

roles:
  passenger:
    rolling_restart_port: "#{passenger_listen_port}"

  web_tools:
    rolling_restart_port: "#{web_tools_port}"

deploy-apache.rb:

on :load do
  rubber.serial_task self, :serial_restart, :roles => [:app, :apache] do
    rsudo "service apache2 restart"
  end
  rubber.serial_task self, :serial_reload, :roles => [:app, :apache] do
    # remove file checked by haproxy to take server out of pool, wait some
    # secs for haproxy to realize it
    maybe_sleep = " && sleep 5" if RUBBER_ENV == 'production'
    rsudo "rm -f #{previous_release}/public/httpchk.txt #{current_release}/public/httpchk.txt#{maybe_sleep}"

    rsudo "if ! ps ax | grep -v grep | grep -c apache2 &> /dev/null; then service apache2 start; else service apache2 reload; fi"

    # Wait for passenger to startup before adding host back into haproxy pool
    logger.info "Waiting for passenger to startup"

    opts = get_host_options('rolling_restart_port') {|port| port.to_s}
    rsudo "while ! curl -s -f http://localhost:$CAPISTRANO:VAR$/ &> /dev/null; do echo .; done", opts

    # Touch the file so that haproxy adds this server back into the pool.
    rsudo "touch #{current_path}/public/httpchk.txt#{maybe_sleep}"
  end
end

after "deploy:restart", "rubber:apache:reload"


desc "Starts the apache web server"
task :start, :roles => :apache do
  rsudo "service apache2 start"
  opts = get_host_options('rolling_restart_port') {|port| port.to_s}
  rsudo "while ! curl -s -f http://localhost:$CAPISTRANO:VAR$/ &> /dev/null; do echo .; done", opts
  rsudo "touch #{current_path}/public/httpchk.txt"
end

回答2:

I got the same error and solved the problem. It was "haproxy" timeout. It is a load balancer installed by Rubber. It is set to 30000ms, you should change it in rubber configuration file.

Good luck!