I’m running into the same error on an new Docker installation of Discourse. It worked fine, then I took it down to set up for Postgres 12 and to enable a static maintenance error page. Now, I can’t get Discourse to run again.
There seems to be an issue with Rails connecting to Redis. From production.log:
Error connecting to Redis on localhost:6379 (Errno::EADDRNOTAVAIL) subscribe failed, reconnecting in 1 second. Call stack ["/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis/client.rb:363:in `rescue in establish_connection'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis/client.rb:344:in `establish_connection'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis/client.rb:106:in `block in connect'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis/client.rb:307:in `with_reconnect'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis/client.rb:105:in `connect'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis/client.rb:382:in `ensure_connected'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis/client.rb:231:in `block in process'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis/client.rb:320:in `logging'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis/client.rb:230:in `process'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis/client.rb:125:in `call'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis.rb:915:in `block in get'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis.rb:51:in `block in synchronize'", "/usr/local/lib/ruby/2.6.0/monitor.rb:235:in `mon_synchronize'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis.rb:51:in `synchronize'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/redis-4.1.4/lib/redis.rb:914:in `get'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/message_bus-3.2.0/lib/message_bus/backends/redis.rb:360:in `process_global_backlog'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/message_bus-3.2.0/lib/message_bus/backends/redis.rb:271:in `block in global_subscribe'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/message_bus-3.2.0/lib/message_bus/backends/redis.rb:284:in `global_subscribe'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/message_bus-3.2.0/lib/message_bus.rb:741:in `global_subscribe_thread'", "/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/message_bus-3.2.0/lib/message_bus.rb:689:in `block in new_subscriber_thread'"]
Creating scope :open. Overwriting existing method Poll.open.
Creating scope :open. Overwriting existing method Poll.open.
Creating scope :open. Overwriting existing method Poll.open.
production_errors.log is empty. Redis seems to start up normally. It’s worth noticing that the syslog contains these lines:
May 17 13:35:30 wobbly-wiki-forum-app rsyslogd: imklog: cannot open kernel log (/proc/kmsg): Operation not permitted.
May 17 13:35:30 wobbly-wiki-forum-app rsyslogd: activation of module imklog failed [v8.1901.0 try https://www.rsyslog.com/e/2145 ]
May 17 13:35:30 wobbly-wiki-forum-app rsyslogd: [origin software="rsyslogd" swVersion="8.1901.0" x-pid="51" x-info="https://www.rsyslog.com"] start
I wonder if they could indicate an issue? FWIW there’s ample available memory and disk space on the server.
EDIT: Now resolved! I was running through an nginx reverse proxy, but had not followed the instructions to the letter. I had forgotten to add the template "templates/web.socketed.template.yml", and I also commented out the entire expose: section of app.yml. Now it works.