default NetworkMode should be "bridge", not "default"

[drice]

https://github.com/docker/docker-py/blob/master/docker/utils/utils.py#L646

 if network_mode:
        host_config['NetworkMode'] = network_mode
    elif network_mode is None and compare_version('1.19', version) > 0:
        host_config['NetworkMode'] = 'default'

should be:

  if network_mode:
        host_config['NetworkMode'] = network_mode
    elif network_mode is None and compare_version('1.19', version) > 0:
        host_config['NetworkMode'] = 'bridge'

The value of "default" gives an error like the following:

FAILED! => {"changed": true, "failed": true, "msg": "Docker API Error: Cannot start container 400145f2e47c2f686abf1513d9d0c49b1fce1e6c8c9f2303c24c61085d5b094c: invalid network mode: default"}

Running on Mac OS 10.11.3

ansible --version
ansible 2.0.1.0
  config file = /etc/ansible/ansible.cfg
  configured module search path = Default w/o overrides

Host is
Ubuntu 15.10

Python 2.7.10
Client version: 1.6.2
Client API version: 1.18
Go version (client): go1.5.1
Git commit (client): 7c8fca2
OS/Arch (client): linux/amd64
Server version: 1.6.2
Server API version: 1.18
Go version (server): go1.5.1
Git commit (server): 7c8fca2
OS/Arch (server): linux/amd64

[drice]

Created PR with this fix:

#987

[shin-]

It seems to be working fine for me.

In [1]: import docker

In [2]: c = docker.Client()

In [3]: c.create_host_config()
Out[3]: {'NetworkMode': 'default'}

In [4]: c.create_container('busybox', 'top', host_config=_3)
Out[4]: 
{u'Id': u'd8a885ec91c58e36c441ed4825528f7e047dfcde5b6678b867afe798a3b32c7d',
 u'Warnings': None}

In [5]: c.start(_4)

In [7]: c.containers()
Out[7]: 
[{u'Command': u'top',
  u'Created': 1457728245,
  u'HostConfig': {u'NetworkMode': u'default'},
  u'Id': u'd8a885ec91c58e36c441ed4825528f7e047dfcde5b6678b867afe798a3b32c7d',
  u'Image': u'busybox',
  u'ImageID': u'sha256:3240943c9ea3f72db51bea0a2428e83f3c5fa1312e19af017d026f9bcf70f84b',
  u'Labels': {},
  u'Names': [u'/high_galileo'],
  u'NetworkSettings': {u'Networks': {u'bridge': {u'Aliases': None,
     u'EndpointID': u'b7df815663775e2f12f2651a6901dfe29d649cac6bb39fc12ed8ed0f4d0f8597',
     u'Gateway': u'172.17.0.1',
     u'GlobalIPv6Address': u'',
     u'GlobalIPv6PrefixLen': 0,
     u'IPAMConfig': None,
     u'IPAddress': u'172.17.0.2',
     u'IPPrefixLen': 16,
     u'IPv6Gateway': u'',
     u'Links': None,
     u'MacAddress': u'02:42:ac:11:00:02',
     u'NetworkID': u''}}},
  u'Ports': [],
  u'Status': u'Up About a minute'}]

Also, note that your host is on API version 1.18, so this shouldn't affect you either way. Maybe ansible is passing the default value to network_mode even though your daemon doesn't support it?

[shin-]

This also appears to be consistent with the CLI's behavior: https://github.com/docker/docker/blob/131e2bf12b2e1b3ee31b628a501f96bbb901f479/runconfig/hostconfig.go#L28-L35

[drice]

It looks like the 1.15 API introduces the NetworkMode option:

https://docs.docker.com/engine/reference/api/docker_remote_api_v1.15/

In the Ansible docker module, there is nothing passed for version to the create_host_config option, so version defaults to 1.21 and causes network_mode to be set to default.

[shin-]

That wouldn't work with your 1.6.2 daemon though (you'd get an error like this one APIError: 400 Client Error: Bad Request "client is newer than server (client API version: 1.23, server API version: 1.22)"

Are you sure your setup is as you describe it?

[drice]

When docker.utils.create_host_config is called:

    if not version:
        warnings.warn(
            'docker.utils.create_host_config() is deprecated. Please use '
            'Client.create_host_config() instead.'
        )
        version = constants.DEFAULT_DOCKER_API_VERSION

sets version = '1.21'

    if network_mode:
        host_config['NetworkMode'] = network_mode
    elif network_mode is None and compare_version('1.19', version) > 0:
        host_config['NetworkMode'] = 'default'

causes host_config['NetworkMode'] to be 'default'.

Parameters passed to create_host_config (as JSON):

{
 "publish_all_ports": true, 
 "links": null, 
 "lxc_conf": null, 
 "network_mode": null, 
 "binds": null, 
 "port_bindings": {
  "2888": [
   "0.0.0.0", 
   2888
  ], 
  "3888": [
   "0.0.0.0", 
   3888
  ], 
  "2181": [
   "0.0.0.0", 
   2181
  ]
 }, 
 "privileged": true
}

HostConfig returned from create_host_config (as JSON):

{
 "PortBindings": {
  "3888/tcp": [
   {
    "HostPort": "3888", 
    "HostIp": "0.0.0.0"
   }
  ], 
  "2181/tcp": [
   {
    "HostPort": "2181", 
    "HostIp": "0.0.0.0"
   }
  ], 
  "2888/tcp": [
   {
    "HostPort": "2888", 
    "HostIp": "0.0.0.0"
   }
  ]
 }, 
 "NetworkMode": "default", 
 "Privileged": true, 
 "PublishAllPorts": true
}

The version is used in the create_host_config function but not set.

[shin-]

Ah, that makes more sense. Your client is using the correct API version, but ansible makes unversioned calls to docker.utils.create_host_config, which it definitely shouldn't be doing. default is causing issues for your setup because the docker version you're using doesn't support that value, which was introduced later.

The reason we're not using bridge as the default value is that the default for Swarm engines is different. The bug should be reported to ansible - their code should be using Client.create_host_config instead of docker.utils.create_host_config.

[drice]

Ok, I'll take it over there.

One question I have is, I only see in 1.21 and later documentation for Docker:

NetworkMode - Sets the networking mode for the container. Supported standard values are: bridge, host, none, and container:<name|id>. Any other value is taken as a custom network’s name to which this container should connect to.

Does this mean the value of "default" is taken as a custom network's name in 1.21+? Is this different behavior than in 1.19/1.20?

[shin-]

default is just missing from the documentation. The daemon interprets it as "default for the current platform", which is bridge for Docker Engine, and overlay for Swarm.

In 1.20, specifying a value for network_mode became mandatory (the server will error out otherwise), which is why we have this special case where we insert a value if it's missing. API versions < 1.20 don't have that restriction, so we leave it to the user to do what they think is best.

See #698 and moby/moby#14530 for more info.

Hope that clears it up!