Output of jekyll from Heroku when it's not properly configured.

jekyll_heroku.log

2013-05-18T19:38:19.642887+00:00 heroku[web.1]: State changed from down to starting
2013-05-18T19:38:19.642887+00:00 heroku[web.1]: Unidling
2013-05-18T19:38:20.473508+00:00 heroku[web.1]: Starting process with command `bundle exec jekyll serve -p 23794`
2013-05-18T19:38:22.046826+00:00 app[web.1]:             Source: /app
2013-05
-18T19:38:22.046657+00:00 app[web.1]: Configuration file: /app/_config.yml
2013-05-18T19:38:22.046826+00:00 app[web.1]:        Destination: /app/_site
2013-05-18T19:38:22.457840+00:00 app[web.1]:       Generating... done.
2013-05-18T19:38:22.535753+00:00 app[web.1]: [2013-05-18 19:38:22] INFO  WEBrick 1.3.1
2013-05-18T19:38:22.535753+00:00 app[web.1]: [2013-05-18 19:38:22] INFO  ruby 1.9.2 (2011-07-09) [x86_64-linux]
2013-05-18T19:38:22.536181+00:00 app[web.1]: [2013-05-18 19:38:22] INFO  WEBrick::HTTPServer#start: pid=2 port=23794
2013-05-18T19:38:22.706050+00:00 heroku[web.1]: State changed from starting to up
2013-05-18T19:38:23.734049+00:00 app[web.1]: ip-10-190-73-50.ec2.internal - - [18/May/2013:19:38:23 UTC] "GET /Procfile HTTP/1.1" 200 39
2013-05-18T19:38:23.733449+00:00 heroku[router]: at=info method=GET path=/Procfile host=jekyll-example-app-123.herokuapp.com fwd="24.212.128.16" dyno=web.1 connect=1ms service=4ms status=200 bytes=39
2013-05-18T19:38:23.734121+00:00 app[web.1]: - -> /Procfile
2013-05-18T19:43:00.239382+00:00 heroku[slugc]: Slug compilation started
2013-05-18T19:43:32.050487+00:00 heroku[api]: Deploy a12b81c by abc@xyz.com
2013-05-18T19:43:32.075601+00:00 heroku[api]: Release v31 created by abc@xyz.com
2013-05-18T19:43:32.167007+00:00 heroku[api]: Deploy a12b81c by abc@xyz.com
2013-05-18T19:43:32.720064+00:00 heroku[web.1]: State changed from up to starting
2013-05-18T19:43:33.118492+00:00 
heroku[slugc]: Slug compilation finished
2013-05-18T19:43:33.500702+00:00 heroku[web.1]: Starting process with command `bundle exec jekyll serve -p 17015`
2013-05-18T19:43:34.610017+00:00 heroku[web.1]: Stopping all processes with SIGTERM
2013-05-18T19:43:35.212355+00:00 app[web.1]: Configuration file: /app/_config.yml
2013-05-18T19:43:35.212752+00:00 app[web.1]:             Source: /app
2013-05-18T19:43:35.212803+00:00 app[web.1]:        Destination: /app/_site
2013-05-18T19:43:35.310320+00:00 app[web.1]:       Generating... Error reading file /app/vendor/bundle/ruby/1.9.1/gems/jekyll-1.0.2/test/fixtures/broken_front_matter3.erb: invalid byte sequence in UTF-8
2013-05-18T19:43:35.310641+00:00 app[web.1]: Error reading file /app/vendor/bundle/ruby/1.9.1/gems/jekyll-1.0.2/test/fixtures/broken_front_matter2.erb: syntax error on line 2, col 0: `'
2013-05-18T19:43:35.311964+00:00 app[web.1]: 
2013-05-18T19:43:35.312077+00:00 app[web.1]:              ERROR: YOUR SITE COULD NOT BE BUILT:
2013-05-18T19:43:35.312077+00:00 app[web.1]:                     ------------------------------------
2013-05-18T19:43:35.312160+00:00 app[web.1]:                     Post 0000-00-00-welcome-to-jekyll.markdown.erb does not have a valid date.
2013-05-18T19:43:36.307690+00:00 heroku[web.1]: Process exited with status 143
2013-05-18T19:43:36.601942+00:00 heroku[web.1]: Process exited with status 1
2013-05-18T19:43:36.633260+00:00 heroku[web.1]: State changed from starting to crashed
2013-05-18T19:43:36.636203+00:00 heroku[web.1]: State changed from crashed to starting
2013-05-18T19:43:38.184319+00:00 heroku[web.1]: Starting process with command `bundle exec jekyll serve -p 16038`
2013-05-18T19:43:44.538378+00:00 app[web.1]: Configuration file: /app/_config.yml
2013-05-18T19:43:44.538987+00:00 app[web.1]:             Source: /app
2013-05-18T19:43:44.539139+00:00 app[web.1]:        Destination: /app/_site
2013-05-18T19:43:45.115944+00:00 app[web.1]:       Generating... Error reading file /app/vendor/bundle/ruby/1.9.1/gems/jekyll-1.0.2/test/fixtures/broken_front_matter2.erb: syntax error on line 2, col 0: `'
2013-05-18T19:43:45.121625+00:00 app[web.1]: Error reading file /app/vendor/bundle/ruby/1.9.1/gems/jekyll-1.0.2/test/fixtures/broken_front_matter3.erb: invalid byte sequence in UTF-8
2013-05-18T19:43:45.594649+00:00 app[web.1]: 
2013-05-18T19:43:45.595120+00:00 app[web.1]:              ERROR: YOUR SITE COULD NOT BE BUILT:
2013-05-18T19:43:45.595389+00:00 app[web.1]:                     ------------------------------------
2013-05-18T19:43:45.597563+00:00 app[web.1]:                     Post 0000-00-00-welcome-to-jekyll.markdown.erb does not have a valid date.
2013-05-18T19:43:47.057449+00:00 heroku[web.1]: Process exited with status 1
2013-05-18T19:43:47.074145+00:00 heroku[web.1]: State changed from starting to crashed

I'm getting this same error but can't work out why. Could you point me in the right direction? What causes this error?

Jekyll is failing because of a vendor directory Heroku adds. Add this to you _config.yml file:

exclude: ['vendor']

For a further explanation see this article: http://markcampbell.me/jekyll/heroku/2013/05/18/how-to-set-up-jekyll-on-heroku.html

Oh my, this fixed my deployment! Thank you!