open-nomad/website/source/docs/drivers/external/lxc.html.md

layout	page_title	sidebar_current	description
docs	Drivers: LXC	docs-drivers-community-lxc	The LXC task driver is used to run application containers using LXC.

LXC Driver

Name: lxc

The lxc driver provides an interface for using LXC for running application containers. You can download the external LXC driver here. For more detailed instructions on how to set up and use this driver, please refer to the LXC guide.

~> The LXC client set up has changed in Nomad 0.9. You must use the new plugin syntax and install the external LXC driver in the plugin_dir prior to upgrading. See plugin options below for an example. Note the job specification remains the same.

Task Configuration

task "busybox" {
  driver = "lxc"

  config {
    log_level = "trace"
    verbosity = "verbose"
    template = "/usr/share/lxc/templates/lxc-busybox"
  }
}

The lxc driver supports the following configuration in the job spec:

• template - The LXC template to run.

  config {
    template = "/usr/share/lxc/templates/lxc-alpine"
  }
  

• log_level - (Optional) LXC library's logging level. Defaults to error. Must be one of trace, debug, info, warn, or error.

  config {
    log_level = "debug"
  }
  

• verbosity - (Optional) Enables extra verbosity in the LXC library's logging. Defaults to quiet. Must be one of quiet or verbose.

  config {
    verbosity = "quiet"
  }
  

• volumes - (Optional) A list of host_path:container_path strings to bind-mount host paths to container paths. Mounting host paths outside of the allocation directory can be disabled on clients by setting the volumes_enabled option set to false. This will limit volumes to directories that exist inside the allocation directory.

  Note that unlike the similar option for the docker driver, this option must not have an absolute path as the container_path component. This will cause an error when submitting a job.

  Setting this does not affect the standard bind-mounts of alloc, local, and secrets, which are always created.

config {
  volumes = [
    # Use absolute paths to mount arbitrary paths on the host
    "/path/on/host:path/in/container",

    # Use relative paths to rebind paths already in the allocation dir
    "relative/to/task:also/in/container"
  ]
}

Networking

Currently the lxc driver only supports host networking. See the none networking type in the lxc.container.conf manual for more information.

Client Requirements

The lxc driver requires the following:

• 64-bit Linux host
• The linux_amd64 Nomad binary
• The LXC driver binary placed in the plugin_dir directory.
• liblxc to be installed
• lxc-templates to be installed

Plugin Options

• enabled - The lxc driver may be disabled on hosts by setting this option to false (defaults to true).

• volumes_enabled - Specifies whether host can bind-mount host paths to container paths (defaults to true).

• lxc_path - The location in which all containers are stored (commonly defaults to /var/lib/lxc). See lxc-create for more details.

An example of using these plugin options with the new plugin syntax is shown below:

plugin "nomad-driver-lxc" {
  config {
    enabled = true
    volumes_enabled = true
    lxc_path = "/var/lib/lxc"
  }
}

Please note the plugin name should match whatever name you have specified for the external driver in the plugin_dir directory.

Client Configuration

~> Only use this section for pre-0.9 releases of Nomad. If you are using Nomad 0.9 or above, please see plugin options

The lxc driver has the following client configuration options:

• lxc.enable - The lxc driver may be disabled on hosts by setting this option to false (defaults to true).

Client Attributes

The lxc driver will set the following client attributes:

• driver.lxc - Set to 1 if LXC is found and enabled on the host node.
• driver.lxc.version - Version of lxc e.g.: 1.1.0.

Resource Isolation

This driver supports CPU and memory isolation via the lxc library. Network isolation is not supported as of now.