Class: OsCtld::Monitor::Process

Inherits:
Object
  • Object
show all
Includes:
OsCtl::Lib::Utils::Log
Defined in:
lib/osctld/monitor/process.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(pool, user, group, stdout, containers:) ⇒ Process

Returns a new instance of Process.



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# File 'lib/osctld/monitor/process.rb', line 57

def initialize(pool, user, group, stdout, containers:)
  @pool = pool
  @user = user
  @group = group
  @stdout = stdout
  @containers = containers
  @last_line = nil
end

Class Method Details

.cgroup_path(ct) ⇒ Object 



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# File 'lib/osctld/monitor/process.rb', line 53

def self.cgroup_path(ct)
  File.join(ct.group.full_cgroup_path(ct.user), 'monitor')
end

.spawn(ct) ⇒ Object 



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# File 'lib/osctld/monitor/process.rb', line 7

def self.spawn(ct)
  cg_path = cgroup_path(ct)
  out_r, out_w = IO.pipe

  CGroup.mkpath_all(cg_path.split('/'))

  pid = Process.fork do
    $stdout.reopen(out_w)
    out_r.close

    SwitchUser.switch_to(
      ct.user.sysusername,
      ct.user.ugid,
      ct.user.homedir,
      cg_path
    )

    Process.exec('lxc-monitor', '-P', ct.lxc_home, '-n', '.*')
  end

  out_w.close
  [pid, out_r]
end

.stop_monitord(ct) ⇒ Object 



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# File 'lib/osctld/monitor/process.rb', line 31

def self.stop_monitord(ct)
  pid = Process.fork do
    SwitchUser.switch_to(
      ct.user.sysusername,
      ct.user.ugid,
      ct.user.homedir,
      cgroup_path(ct)
    )

    Process.exec('lxc-monitor', '-P', ct.lxc_home, '--quit')
  end

  _, status = Process.wait2(pid)

  if status.exitstatus == 0
    log(:info, :monitor, 'Stopped lxc-monitord')

  else
    log(:info, :monitor, 'Failed to stop lxc-monitord')
  end
end

Instance Method Details

#cancel_exited_run(ct) ⇒ Object (protected) 



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# File 'lib/osctld/monitor/process.rb', line 188

def cancel_exited_run(ct)
  ct.run_conf&.nfs_cancellation&.abort
rescue StandardError => e
  # A failed cancellation must be visible without killing the shared
  # pool/user/group monitor and losing future state changes.
  log(:warn, :monitor, "Unable to cancel NFS for exited container #{ct.ident}: #{e.message}")
end

#check_exiting_runs ⇒ Object (protected) 



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# File 'lib/osctld/monitor/process.rb', line 99

def check_exiting_runs
  @containers.call.each do |ct|
    next unless ct.pool == @pool && ct.user == @user && ct.group == @group

    run_conf = ct.run_conf
    next unless run_conf

    run_conf.nfs_cancellation.capture(run_conf.init_pid)
    run_conf.nfs_cancellation.abort_if_exiting
  rescue StandardError => e
    log(:warn, :monitor, "Unable to check exiting container #{ct.ident}: #{e.message}")
  end
end

#monitor ⇒ Object 



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# File 'lib/osctld/monitor/process.rb', line 66

def monitor
  exit_checks = Queue.new
  exit_thread = Thread.new do
    check_exiting_runs until exit_checks.pop(timeout: 1)
  end

  until @stdout.eof?
    line = @stdout.readline
    next if line == @last_line

    @last_line = line

    state = parse(line)
    next unless state

    update_state(state)
  end

  true
rescue IOError
  log(:info, :monitor, "Monitoring of #{@pool.name}:#{@user.name}:#{@group.name} failed")
  false
ensure
  begin
    exit_checks << true if exit_checks
    exit_thread&.join
  ensure
    @stdout.close unless @stdout.closed?
  end
end

#parse(line) ⇒ Object (protected) 



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# File 'lib/osctld/monitor/process.rb', line 113

def parse(line)
  if /'([^']+)' changed state to \[([^\]]+)\]/ =~ line
    log(:info, :monitor, "Container #{@pool.name}:#{::Regexp.last_match(1)} entered state #{::Regexp.last_match(2)}")
    return { pool: @pool.name, ctid: ::Regexp.last_match(1), state: ::Regexp.last_match(2).downcase.to_sym }

  elsif /'([^']+)' exited with status \[(\d+)\]/ =~ line
    log(:info, :monitor, "Container #{@pool.name}:#{::Regexp.last_match(1)} exited with #{::Regexp.last_match(2)}")

  else
    log(:warn, :monitor, "Line from lxc-monitor not recognized: '#{line}'")
  end

  nil
end

#update_state(change) ⇒ Object (protected) 



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# File 'lib/osctld/monitor/process.rb', line 128

def update_state(change)
  ct = DB::Containers.find(change[:ctid], change[:pool])

  unless ct
    log(:warn, :monitor, "Container #{change[:pool]}:#{change[:ctid]} not found")
    return
  end

  return if ct.state == :error

  # PID1 has exited by STOPPING, but the LXC monitor can still block while
  # releasing NFS mounts. Cancel the retained run before publishing a
  # terminal state that lets a new start discard its namespace handles.
  if %i[stopping stopped aborted].include?(change[:state])
    cancel_exited_run(ct)
  end

  # When transitioning to `running`, send the event only after init_pid was set
  # below, so that when {Commands::Container::Start} finishes waiting and returns,
  # the init_pid is not nil.
  if change[:state] != :running
    Eventd.report(:state, pool: ct.pool.name, id: ct.id, state: change[:state])
  end

  ct.state = change[:state]
  init_pid = nil

  case ct.state
  when :running
    begin
      init_pid = wait_for_init_pid(ct)
      if init_pid
        init_pid = ct.set_init_pid(init_pid)
        ct.ensure_run_conf.nfs_cancellation.capture(init_pid) if init_pid
      end
    rescue ContainerControl::Error, SystemCallError, IOError => e
      init_pid = nil
      log(:warn, :monitor, "Unable to get state of container #{ct.ident}: #{e.message}")
    end

    Eventd.report(:state, pool: ct.pool.name, id: ct.id, state: change[:state])

    if init_pid
      Eventd.report(:ct_init_pid, pool: ct.pool.name, id: ct.id, init_pid:)
    end

    Hook.run(ct, :post_start, init_pid: ct.init_pid)

  when :aborting
    # It has happened that ct.run_conf was nil, circumstances unknown
    ct.ensure_run_conf.aborted = true

  when :stopping
    Hook.run(ct, :on_stop)

  when :stopped, :aborted
    ct.mounts.prune
  end
end

#wait_for_init_pid(ct) ⇒ Object (protected) 



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# File 'lib/osctld/monitor/process.rb', line 196

def wait_for_init_pid(ct)
  deadline = Time.now + 10
  st = nil

  loop do
    st = ContainerControl::Commands::State.run!(ct)
    return st.init_pid if st.init_pid
    break if Time.now >= deadline

    sleep(0.1)
  end

  log(:warn, :monitor, "Container #{ct.ident} is running without an init PID, last LXC state was #{st&.state || 'unknown'}")
  nil
end