Merge pull request #2846 from DataDog/jaime/docker_fixyaml

[docker_daemon] custom cgroups are per instance only. YAML updates.

checks.d/docker_daemon.py

@@ -155,7 +155,6 @@ def __init__(self, name, init_config, agentConfig, instances=None):
         self._service_discovery = agentConfig.get('service_discovery') and \
             agentConfig.get('service_discovery_backend') == 'docker'
         self.init()
-        self._custom_cgroups = _is_affirmative(init_config.get('custom_cgroups', False))
 
     def init(self):
         try:
@@ -249,11 +248,11 @@ def check(self, instance):
                 self.kube_labels = {}
 
         # containers running with custom cgroups?
-        custom_cgroups = _is_affirmative(instance.get('custom_cgroups', self._custom_cgroups))
+        custom_cgroups = _is_affirmative(instance.get('custom_cgroups', False))
 
         # Get the list of containers and the index of their names
         containers_by_id = self._get_and_count_containers(custom_cgroups)
-        containers_by_id = self._crawl_container_pids(containers_by_id)
+        containers_by_id = self._crawl_container_pids(containers_by_id, custom_cgroups)
 
         # Send events from Docker API
         if self.collect_events or self._service_discovery:
@@ -807,7 +806,7 @@ def _parse_blkio_metrics(self, stats):
         return metrics
 
     # proc files
-    def _crawl_container_pids(self, container_dict):
+    def _crawl_container_pids(self, container_dict, custom_cgroups=False):
         """Crawl `/proc` to find container PIDs and add them to `containers_by_id`."""
         proc_path = os.path.join(self.docker_util._docker_root, 'proc')
         pid_dirs = [_dir for _dir in os.listdir(proc_path) if _dir.isdigit()]
@@ -861,7 +860,7 @@ def _crawl_container_pids(self, container_dict):
                         continue
                     container_dict[container_id]['_pid'] = folder
                     container_dict[container_id]['_proc_root'] = os.path.join(proc_path, folder)
-                elif self._custom_cgroups: # if we match by pid that should be enough (?) - O(n) ugh!
+                elif custom_cgroups: # if we match by pid that should be enough (?) - O(n) ugh!
                     for _, container in container_dict.iteritems():
                         if container.get('_pid') == int(folder):
                             container['_proc_root'] = os.path.join(proc_path, folder)

conf.d/docker.yaml.example

@@ -12,12 +12,6 @@ init_config:
   # Timeout on Docker socket connection. You may have to increase it if you have many containers.
   # socket_timeout: 5
 
-  # Do you use custom cgroups for your containers? Also relevant if using systemd-docker.
-  # Note: enabling this option modifies the way in which we inspect the containers and causes
-  #       some overhead - if you run a high volume of containers we may timeout. Please only
-  #       enable if absolutely necessary.
-  # custom_cgroups: false
-
 instances:
     # URL of the Docker daemon socket to reach the Docker API. HTTP also works.
   - url: "unix://var/run/docker.sock"
@@ -61,12 +55,6 @@ instances:
     #
     # collect_events: true
     #
-    #
-    # Do you use custom cgroups for this particular instance? Overrides the init_config setting.
-    # Note: enabling this option modifies the way in which we inspect the containers and causes
-    #       some overhead - if you run a high volume of containers we may timeout. Please only
-    #       enable if absolutely necessary.
-    # custom_cgroups: false
 
     # Collect disk usage per container with docker.disk.size metric.
     # Warning: This feature is broken in some version of Docker (such as 1.2).

conf.d/docker_daemon.yaml.example

@@ -45,6 +45,12 @@ instances:
     #
     # collect_container_size: false
 
+    # Do you use custom cgroups for this particular instance?
+    # Note: enabling this option modifies the way in which we inspect the containers and causes
+    #       some overhead - if you run a high volume of containers we may timeout. Please only
+    #       enable if absolutely necessary.
+    # custom_cgroups: false
+
     # Collect images stats
     # Number of available active images and intermediate images as gauges.
     # Defaults to false.