Revert "Merge pull request #16130 from jrafanie/fork_workers_no_more"

Gemfile

@@ -41,6 +41,7 @@ gem "manageiq-api-client", "~>0.1.0", :require => false
 gem "manageiq-network_discovery", "~>0.1.2", :require => false
 gem "mime-types", "~>2.6.1", :path => "mime-types-redirector"
 gem "more_core_extensions", "~>3.3"
+gem "nakayoshi_fork", "~>0.0.3" # provides a more CoW friendly fork (GC a few times before fork)
 gem "net-ldap", "~>0.14.0", :require => false
 gem "net-ping", "~>1.7.4", :require => false
 gem "net-ssh", "=3.2.0", :require => false

app/models/miq_worker.rb

@@ -304,6 +304,29 @@ def send_message_to_worker_monitor(message, *args)
  )
  end
 
+ def self.before_fork
+ preload_for_worker_role if respond_to?(:preload_for_worker_role)
+ end
+
+ def self.after_fork
+ close_pg_sockets_inherited_from_parent
+ DRb.stop_service
+ renice(Process.pid)
+ end
+
+ # When we fork, the children inherits the parent's file descriptors
+ # so we need to close any inherited raw pg sockets in the child.
+ def self.close_pg_sockets_inherited_from_parent
+ owner_to_pool = ActiveRecord::Base.connection_handler.instance_variable_get(:@owner_to_pool)
+ owner_to_pool[Process.ppid].values.compact.each do |pool|
+ pool.connections.each do |conn|
+ socket = conn.raw_connection.socket
+ _log.info("Closing socket: #{socket}")
+ IO.for_fd(socket).close
+ end
+ end
+ end
+
  # Overriding queue_name as now some queue names can be
  # arrays of names for some workers not just a singular name.
  # We use JSON.parse as the array of names is stored as a string.
@@ -316,6 +339,26 @@ def queue_name
  end
  end
 
+ def start_runner
+ if ENV['MIQ_SPAWN_WORKERS'] || !Process.respond_to?(:fork)
+ start_runner_via_spawn
+ else
+ start_runner_via_fork
+ end
+ end
+
+ def start_runner_via_fork
+ self.class.before_fork
+ pid = fork(:cow_friendly => true) do
+ self.class.after_fork
+ self.class::Runner.start_worker(worker_options)
+ exit!
+ end
+
+ Process.detach(pid)
+ pid
+ end
+
  def self.build_command_line(guid)
  command_line = "#{Gem.ruby} #{runner_script} --heartbeat --guid=#{guid} #{name}"
  ENV['APPLIANCE'] ? "nice #{nice_increment} #{command_line}" : command_line
@@ -327,7 +370,7 @@ def self.runner_script
  script
  end
 
- def start_runner
+ def start_runner_via_spawn
  pid = Kernel.spawn(self.class.build_command_line(guid), [:out, :err] => [Rails.root.join("log", "evm.log"), "a"])
  Process.detach(pid)
  pid

lib/workers/bin/run_single_worker.rb

@@ -55,7 +55,7 @@
 require File.expand_path("../../../config/environment", __dir__)
 
 worker_class = worker_class.constantize
-worker_class.preload_for_worker_role if worker_class.respond_to?(:preload_for_worker_role)
+worker_class.before_fork
 unless options[:dry_run]
  create_options = {:pid => Process.pid}
  runner_options = {}