Unicorn 0.97.0 old master is never dying

ghazel at gmail.com ghazel at gmail.com
Fri Mar 19 04:55:32 EDT 2010

>> Here is the entire config file: http://codepad.org/v6lUsuzD
> Ugh.  I can't even get to that file right now.  I actually prefer
> to have config files inline so:
> a) I can comment easily on them
> b) I don't have to be online when reading them
>   (I sync my mail to a local machine and lose connectivity often)

We're still working on that internet that works when you're not
online. In the meantime:

# Sample configuration file for Unicorn (not Rack)
# See http://unicorn.bogomips.org/Unicorn/Configurator.html for complete
# documentation.

require '/data/myapp/current/config/unicorn_constants'

# Use at least one worker per core if you're on a dedicated server,
# more will usually help for _short_ waits on databases/caches.
worker_processes UnicornConstants::NUM_WORKERS

# Help ensure your application will always spawn in the symlinked
# "current" directory that Capistrano sets up.
working_directory "/data/myapp/current" # available in 0.94.0+

# listen on both a Unix domain socket and a TCP port,
# we use a shorter backlog for quicker failover when busy
listen "/tmp/unicorn.sock", :backlog => 64
listen 8080, :tcp_nopush => true, :tries => -1

# nuke workers after X seconds instead of (60 seconds default)
timeout 300

# feel free to point this anywhere accessible on the filesystem
pid "/data/myapp/shared/pids/unicorn.pid"

# some applications/frameworks log to stderr or stdout, so prevent
# them from going to /dev/null when daemonized here:
stderr_path "/data/myapp/shared/log/unicorn.stderr.log"
stdout_path "/data/myapp/shared/log/unicorn.stdout.log"

# combine REE with "preload_app true" for memory savings
# http://rubyenterpriseedition.com/faq.html#adapt_apps_for_cow
preload_app true
GC.respond_to?(:copy_on_write_friendly=) and
  GC.copy_on_write_friendly = true

before_fork do |server, worker|
  # the following is highly recomended for Rails + "preload_app true"
  # as there's no need for the master process to hold a connection
  defined?(ActiveRecord::Base) and

  # The following is only recommended for memory/DB-constrained
  # installations.  It is not needed if your system can house
  # twice as many worker_processes as you have configured.
  # This allows a new master process to incrementally
  # phase out the old master process with SIGTTOU to avoid a
  # thundering herd (especially in the "preload_app false" case)
  # when doing a transparent upgrade.  The last worker spawned
  # will then kill off the old master process with a SIGQUIT.
  old_pid = "#{server.config[:pid]}.oldbin"
  if File.exists?(old_pid) && server.pid != old_pid
      Process.kill("QUIT", File.read(old_pid).to_i)
    rescue Errno::ENOENT, Errno::ESRCH
      # someone else did our job for us

after_fork do |server, worker|
  # per-process listener ports for debugging/admin/migrations
  addr = "{9000 + worker.nr}"
  server.listen(addr, :tries => -1, :delay => 5, :tcp_nopush => true)

  # the following is *required* for Rails + "preload_app true",
  defined?(ActiveRecord::Base) and

  # if preload_app is true, then you may also want to check and
  # restart any other shared sockets/descriptors such as Memcached,
  # and Redis.  TokyoCabinet file handles are safe to reuse
  # between any number of forked children (assuming your kernel
  # correctly implements pread()/pwrite() system calls)


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