Heroku: Cannot run more than 1 Free size dynos
Most Efective
in console run:
heroku psthe result is some like this:
run.4859 (Free): up 2016/01/12 21:28:41 (~ 7m ago): rails cSo the numbers 4859 represent the session that is open and needs to be closed. To fix the error you need to run(Obviusly, replace the number 4859 by the number obtained):
heroku ps:stop run.4859It is a very simple solution.
The answer is to look for any open heroku sessions (you can use 'heroku ps' as john points out below), in my case I already had a started a heroku console session 30mins earlier and just forgot about it. So if you see the "Cannot run more than 1 Free size dynos" error just close any existing console or other heroku sessions you have open.
Hopefully this saves someone the ten minutes it took me to come to my senses.
Had the exact same issue and came to this page. After reading realized what was going on but want to add following.
just run
heroku kill DYNO --app your_app_nameAfter this close all open consoles.
Then run db migrate command, it will work.