api: add cgroupns option to container create (#2930)

Signed-off-by: David Otto <ottodavid@gmx.net>

docker/models/containers.py

@@ -553,6 +553,11 @@ class ContainerCollection(Collection):
                 ``["SYS_ADMIN", "MKNOD"]``.
             cap_drop (list of str): Drop kernel capabilities.
             cgroup_parent (str): Override the default parent cgroup.
+            cgroupns (str): Override the default cgroup namespace mode for the
+                container. One of:
+                - ``private`` the container runs in its own private cgroup
+                  namespace.
+                - ``host`` use the host system's cgroup namespace.
             cpu_count (int): Number of usable CPUs (Windows only).
             cpu_percent (int): Usable percentage of the available CPUs
                 (Windows only).
@@ -1002,6 +1007,7 @@ RUN_HOST_CONFIG_KWARGS = [
     'cap_add',
     'cap_drop',
     'cgroup_parent',
+    'cgroupns',
     'cpu_count',
     'cpu_percent',
     'cpu_period',

docker/types/containers.py

@@ -272,7 +272,8 @@ class HostConfig(dict):
                  volume_driver=None, cpu_count=None, cpu_percent=None,
                  nano_cpus=None, cpuset_mems=None, runtime=None, mounts=None,
                  cpu_rt_period=None, cpu_rt_runtime=None,
-                 device_cgroup_rules=None, device_requests=None):
+                 device_cgroup_rules=None, device_requests=None,
+                 cgroupns=None):
 
         if mem_limit is not None:
             self['Memory'] = parse_bytes(mem_limit)
@@ -646,6 +647,9 @@ class HostConfig(dict):
                     req = DeviceRequest(**req)
                 self['DeviceRequests'].append(req)
 
+        if cgroupns:
+            self['CgroupnsMode'] = cgroupns
+
 
 def host_config_type_error(param, param_value, expected):
     error_msg = 'Invalid type for {0} param: expected {1} but found {2}'

tests/unit/models_containers_test.py

@@ -39,6 +39,7 @@ class ContainerCollectionTest(unittest.TestCase):
             cap_add=['foo'],
             cap_drop=['bar'],
             cgroup_parent='foobar',
+            cgroupns='host',
             cpu_period=1,
             cpu_quota=2,
             cpu_shares=5,
@@ -135,6 +136,7 @@ class ContainerCollectionTest(unittest.TestCase):
                 'BlkioWeight': 2,
                 'CapAdd': ['foo'],
                 'CapDrop': ['bar'],
+                'CgroupnsMode': 'host',
                 'CgroupParent': 'foobar',
                 'CpuPeriod': 1,
                 'CpuQuota': 2,