pumaのproduction用設定

config/puma.rb

# Puma can serve each request in a thread from an internal thread pool.
# The `threads` method setting takes two numbers: a minimum and maximum.
# Any libraries that use thread pools should be configured to match
# the maximum value specified for Puma. Default is set to 5 threads for minimum
# and maximum; this matches the default thread size of Active Record.
#
max_threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }
min_threads_count = ENV.fetch("RAILS_MIN_THREADS") { max_threads_count }
threads min_threads_count, max_threads_count

# Specifies the `port` that Puma will listen on to receive requests; default is 3000.
#
# port        ENV.fetch("PORT") { 3000 } # ここをコメントアウトなり消すなり
bind "unix://#{Rails.root}/tmp/sockets/puma.sock" # 追記
daemonize # 追記
stdout_redirect "#{Rails.root}/log/stdout", "#{Rails.root}/log/stderr" # 追記

以下、省略
...

実行時

rails s -e production