.. _config_lxc:

======================== Getting Started With LXC

The LXC module is designed to install Salt in an LXC container on a controlled and possibly remote minion.

In other words, Salt will connect to a minion, then from that minion:

Provision and configure a container for networking access
Use those modules to deploy salt and re-attach to master.
- :mod:lxc runner <salt.runners.lxc>
- :mod:lxc module <salt.modules.lxc>
- :mod:seed <salt.modules.config>

Limitations

You can only act on one minion and one provider at a time.
Listing images must be targeted to a particular LXC provider (nothing will be outputted with all)

Operation

Salt's LXC support does use :mod:lxc.init <salt.modules.lxc.init> via the :mod:lxc.cloud_init_interface <salt.modules.lxc.cloud_init_interface> and seeds the minion via :mod:seed.mkconfig <salt.modules.seed.mkconfig>.

You can provide to those lxc VMs a profile and a network profile like if you were directly using the minion module.

Order of operation:

Create the LXC container on the desired minion (clone or template)
Change LXC config options (if any need to be changed)
Start container
Change base passwords if any
Change base DNS configuration if necessary
Wait for LXC container to be up and ready for ssh
Test SSH connection and bailout in error
Upload deploy script and seeds, then re-attach the minion.

Provider configuration

Here is a simple provider configuration:

.. code-block:: yaml

# Note: This example goes in /etc/salt/cloud.providers or any file in the
# /etc/salt/cloud.providers.d/ directory.
devhost10-lxc:
  target: devhost10
  driver: lxc

.. note:: .. versionchanged:: 2015.8.0

The ``provider`` parameter in cloud provider definitions was renamed to ``driver``. This
change was made to avoid confusion with the ``provider`` parameter that is used in cloud profile
definitions. Cloud provider definitions now use ``driver`` to refer to the Salt cloud module that
provides the underlying functionality to connect to a cloud host, while cloud profiles continue
to use ``provider`` to refer to provider configurations that you define.

Profile configuration

Please read :ref:tutorial-lxc before anything else. And specially :ref:tutorial-lxc-profiles.

Here are the options to configure your containers:

target
    Host minion id to install the lxc Container into
lxc_profile
    Name of the profile or inline options for the LXC vm creation/cloning,
    please see :ref:`tutorial-lxc-profiles-container`.
network_profile
    Name of the profile or inline options for the LXC vm network settings,
    please see :ref:`tutorial-lxc-profiles-network`.
nic_opts
    Totally optional.
    Per interface new-style configuration options mappings which will
    override any profile default option::

          eth0: {'mac': '00:16:3e:01:29:40',
                        'gateway': None, (default)
                        'link': 'br0', (default)
                        'gateway': None, (default)
                        'netmask': '', (default)
                        'ip': '22.1.4.25'}}

password
    password for root and sysadmin users
dnsservers
    List of DNS servers to use. This is optional.
minion
    minion configuration (see :ref:`Minion Configuration in Salt Cloud <salt-cloud-config>`)
bootstrap_delay
    specify the time to wait (in seconds) between container creation
    and salt bootstrap execution. It is useful to ensure that all essential services
    have started before the bootstrap script is executed. By default there's no
    wait time between container creation and bootstrap unless you are on systemd
    where we wait that the system is no more in starting state.
bootstrap_shell
    shell for bootstraping script (default: /bin/sh)
script
    defaults to salt-boostrap
script_args
    arguments which are given to the bootstrap script.
    the {0} placeholder will be replaced by the path which contains the
    minion config and key files, eg::

        script_args="-c {0}"

Using profiles:

.. code-block:: yaml

# Note: This example would go in /etc/salt/cloud.profiles or any file in the
# /etc/salt/cloud.profiles.d/ directory.
devhost10-lxc:
  provider: devhost10-lxc
  lxc_profile: foo
  network_profile: bar
  minion:
    master: 10.5.0.1
    master_port: 4506

Using inline profiles (eg to override the network bridge):

.. code-block:: yaml

devhost11-lxc:
  provider: devhost10-lxc
  lxc_profile:
    clone_from: foo
  network_profile:
    etho:
      link: lxcbr0
  minion:
    master: 10.5.0.1
    master_port: 4506

Using a lxc template instead of a clone:

.. code-block:: yaml

devhost11-lxc:
  provider: devhost10-lxc
  lxc_profile:
    template: ubuntu
    # options:
    #   release: trusty
  network_profile:
    etho:
      link: lxcbr0
  minion:
    master: 10.5.0.1
    master_port: 4506

Static ip:

.. code-block:: yaml

# Note: This example would go in /etc/salt/cloud.profiles or any file in the
# /etc/salt/cloud.profiles.d/ directory.
devhost10-lxc:
  provider: devhost10-lxc
  nic_opts:
    eth0:
      ipv4: 10.0.3.9
  minion:
    master: 10.5.0.1
    master_port: 4506

DHCP:

.. code-block:: yaml

# Note: This example would go in /etc/salt/cloud.profiles or any file in the
# /etc/salt/cloud.profiles.d/ directory.
devhost10-lxc:
  provider: devhost10-lxc
  minion:
    master: 10.5.0.1
    master_port: 4506

Driver Support

Container creation
Image listing (LXC templates)
Running container information (IP addresses, etc.)