Rails application deployed on Elastic Beanstalk with Puma fails - 502 errors on every request

Question

I just deployed a Rails app to Elastic Beanstalk, and every request is giving me a 502 error.

Here's the contents of /var/logs/nginx/error.log

2015/05/20 16:24:25 [warn] 1535#0: conflicting server name "localhost" on 0.0.0.0:80, ignored
2015/05/20 16:27:12 [crit] 1537#0: *20 connect() to unix:///var/run/puma/my_app.sock failed (2: No such file or directory) while connecting to upstream, client: 172.31.51.94, server: _, request: "POST /get HTTP/1.1", upstream: "http://unix:///var/run/puma/my_app.sock:/get", host: "securities-api-prod.elasticbeanstalk.com"
2015/05/20 16:27:17 [crit] 1537#0: *20 connect() to unix:///var/run/puma/my_app.sock failed (2: No such file or directory) while connecting to upstream, client: 172.31.51.94, server: _, request: "POST /get HTTP/1.1", upstream: "http://unix:///var/run/puma/my_app.sock:/get", host: "securities-api-prod.elasticbeanstalk.com"
2015/05/20 16:27:19 [crit] 1537#0: *20 connect() to unix:///var/run/puma/my_app.sock failed (2: No such file or directory) while connecting to upstream, client: 172.31.51.94, server: _, request: "POST /get HTTP/1.1", upstream: "http://unix:///var/run/puma/my_app.sock:/get", host: "securities-api-prod.elasticbeanstalk.com"
2015/05/20 16:27:22 [crit] 1537#0: *16 connect() to unix:///var/run/puma/my_app.sock failed (2: No such file or directory) while connecting to upstream, client: 172.31.44.210, server: _, request: "GET /datapoint?tickers=AAPL&datapoints=Ratings HTTP/1.1", upstream: "http://unix:///var/run/puma/my_app.sock:/datapoint?tickers=AAPL&datapoints=Ratings", host: "securities-api-prod.elasticbeanstalk.com"
2015/05/20 16:27:27 [crit] 1537#0: *20 connect() to unix:///var/run/puma/my_app.sock failed (2: No such file or directory) while connecting to upstream, client: 172.31.51.94, server: _, request: "POST /get HTTP/1.1", upstream: "http://unix:///var/run/puma/my_app.sock:/get", host: "securities-api-prod.elasticbeanstalk.com"
2015/05/20 16:27:32 [crit] 1537#0: *20 connect() to unix:///var/run/puma/my_app.sock failed (2: No such file or directory) while connecting to upstream, client: 172.31.51.94, server: _, request: "POST /get HTTP/1.1", upstream: "http://unix:///var/run/puma/my_app.sock:/get", host: "securities-api-prod.elasticbeanstalk.com"
2015/05/20 16:28:53 [crit] 1537#0: *52 connect() to unix:///var/run/puma/my_app.sock failed (2: No such file or directory) while connecting to upstream, client: 172.31.51.94, server: _, request: "GET /datapoint?tickers=AAPL&datapoints=Ratings HTTP/1.1", upstream: "http://unix:///var/run/puma/my_app.sock:/datapoint?tickers=AAPL&datapoints=Ratings", host: "securities-api-prod.elasticbeanstalk.com"
2015/05/20 16:30:47 [crit] 1537#0: *69 connect() to unix:///var/run/puma/my_app.sock failed (2: No such file or directory) while connecting to upstream, client: 172.31.51.94, server: _, request: "POST /get HTTP/1.1", upstream: "http://unix:///var/run/puma/my_app.sock:/get", host: "securities-api-prod.elasticbeanstalk.com"

I think puma is running -

[ec2-user@ip-172-31-44-135 nginx]$ ps aux | grep puma
root     23299  1.0  0.2  53008  1428 ?        Ss   16:38   0:00 su -s /bin/bash -c puma -C /opt/elasticbeanstalk/support/conf/pumaconf.rb webapp
webapp   23314  0.0  2.4  75764 14604 ?        Rsl  16:38   0:00 /opt/rubies/ruby-2.1.4/bin/ruby /opt/rubies/ruby-2.1.4/bin/puma -C /opt/elasticbeanstalk/support/conf/pumaconf.rb
ec2-user 23317  0.0  0.1 110284   844 pts/0    S+   16:38   0:00 grep puma

pumaconf.rb

directory '/var/app/current'
threads 8, 32
workers %x(grep -c processor /proc/cpuinfo)
bind 'unix:///var/run/puma/my_app.sock'
stdout_redirect '/var/log/puma/puma.log', '/var/log/puma/puma.log', true
daemonize false

Anyone know what's going on?

Answer 1

I faced the same error and adding these two lines to config/puma.rb fixed the problem:

bind "unix:///var/run/puma/my_app.sock"
pidfile "/var/run/puma/my_app.sock"

After this step I faced another error to add ENV values, which is very straight forward.

Hope this helps.

Answer 2

Sorry - Super late to the game. But I found this entry when searching for the same error message and could solve it differently.

I am trying to let a Rails 6.1.1 (currently latest and greatest) application run on AWS Beanstalk (Puma with Ruby 2.6), where I got the same error as described in this post: Nginx throwing above connection error / Puma seems not reactive (no entries in puma logs) / When SSHing into the machine it shows Puma is running (initctl status puma -> shows process ID).

After some days of research (and trying all above answers without success) - I switched to Passenger - but still same result. Researching the same problem for Passenger showed the proper solution:

Do not use the gem of the application server in production when you want to use the already provided application server of the AWS platform branch ("Puma with Ruby 2.6..." or "Passenger with Ruby 2.6...") (it somehow collides with the already installed version). Therefore in your Gemfile:

gem 'puma', '~> 5.0', groups: [:development, :test]

respectively:

gem "passenger", ">= 5.3.2", require: "phusion_passenger/rack_handler", groups: [:development, :test]

or use the AWS Beanstalk platform without already installed application server ("Ruby 2.6 running on...)

PS: Seems to be only a solution for higher Rails versions (my old Rails 5.1 app runs perfectly on the "Puma with Ruby 2.6" platform even with the gem "normally" installed.

Answer 3

In my case, this was happening because of a Gem loading error. I was able to reproduce the error by connecting to the server with eb ssh and running pumactl start.

For me, the conflict was with the nio4r gem, although for others it was the puma gem. Setting it to the same version as the Elastic Beanstalk platform's gem fixed the error.

More details here: https://stackoverflow.com/a/67110462/1852005 and here: https://forums.aws.amazon.com/thread.jspa?messageID=957426

Answer 4

Changing config.force_ssl = true to false fixed the issue for me.