Adding your first devices

Caution

Do not rush. Always start with QEMU testing, then add a real device which is well supported by LAVA. Purchase and integrate one of the standard known devices. Take time to learn what is required to automate a DUT. Avoid rushing into adding your own new device type. When you have a LAVA instance which has successfully run a few dozen test jobs using QEMU and a standard known device, then consider how to integrate a new device-type into LAVA.

Django administration interface

The django admin interface is a core component of the django framework. Elements can be added for particular implementations but, fundamentally, the operation of the interface is the same as other django sites. The appearance of the menu is determined by the version of django installed on your system. The style changed substantially in django 1.9, so images of the interface itself are not included here.

Changes within the administration interface and changes made as a superuser through the UI are tracked through the History elements of objects in the database. When viewing a specific element (for example a single Test Job or a single Device), click on the History link to view all changes relating to that element. There is also a link back to the UI view of the same element.

Note

the organisation, layout and content of the django administration interface is subject to change with upgrades to django itself and these changes are outside the control of LAVA.

Start with a known device type

It is tempting to jump straight in with your one-off special device which nobody else has managed to automate yet but a fresh install needs to be tested with a known working configuration. Setting up known working devices and learning how to modify the first job is essential to deciding how to best configure a new device. It is also recommended to setup another known device type which is similar to the device you want to add as there are different steps required for certain types of device.

This first QEMU device can be configured on the existing worker which is always available on the master. Subsequent devices can be added to other workers and devices can be shuffled between workers, subject to limitations of physical connections.

QEMU

QEMU is always recommended as the first device to be set up on any LAVA instance for a few reasons:

  1. QEMU requires no external hardware or software configuration (until a network bridge becomes desirable)
  2. QEMU requires only a minimal device dictionary.
  3. Test images for use with QEMU are readily available and relatively easy to modify.

Create a Device Type

Prior to adding any devices, admins should add suitable device types to the database. The device type name should match a jinja2 template file in:

/etc/lava-server/dispatcher-config/device-types/

If an existing template does not exist, a new template will need to be created.

See also

Device types

You can then either use the web admin interface or the lava-server command line to add device types.

Using the admin interface

In order to use the web admin interface, log in to the LAVA instance and click on your username to see the Profile menu.

_images/profile-menu.png

The django administrative interface is accessed from the Administration link in the profile menu.

  1. Scroll down to the group labelled LAVA_SCHEDULER_APP.
  2. Click on Device types

Just before you add the device type, take a look at the available elements of a device type:

  • Name
  • Has health check
  • Display
  • Owners only
  • Health check frequency
  • Architecture name
  • Processor name
  • CPU model name
  • List of cores
  • Bit count

The only value needed for the QEMU device type is the Name, just check that Display is the default: enabled. Now Save.

Using the command line

On the command line, you can add device types (for instance QEMU and panda) using:

lava-server manage device-types add qemu
lava-server manage device-types add panda

It’s also possible to add all known device types at the same time with:

lava-server manage device-types add '*'

Descriptive fields like Architecture name, Processor name, CPU model name, List of cores and Bit count cannot be set on the command line.

Using the command line interface it’s also possible to list all known device types:

lava-server manage device-types list --all

Create a device in the database

Using the admin interface

  • Navigate back to LAVA_SCHEDULER_APP and select Devices and Add Device.
  • Select the QEMU device type from the list.
  • Give your device a name
  • Select the worker from the list.
  • Set the Device owner (typically one of the superusers).
  • Your first device should be public.
  • Ensure that the device is enabled as a Pipeline device.

Using the command line

Using the command line interface it’s also possible to list all known device types:

lava-server manage device-types list -a

On the command line, you can add device types (for instance a QEMU type device with a hostname qemu01) using:

lava-server manage devices add --device-type qemu --worker <worker> qemu01

See lava-server manage help devices for more options, including initial states of the device in the database.

Adding a dictionary to the first QEMU device

For the first device, a simple device dictionary can be used to provide the device-specific details on top of the template:

{% extends 'qemu.jinja2' %}
{% set mac_addr = '52:54:00:12:34:59' %}
{% set memory = '1024' %}
  • The device dictionary must extend an existing template.

  • The architecture (arch value) is not set in this device dictionary. This allows this device to run test jobs using files for any architecture supported by QEMU.

  • The MAC address needs to differ for each device of this type across all instances on the same subnet.

  • The available memory for the virtual machine is set in megabytes. This can be changed later to balance the requirements of test jobs with performance on the worker.

  • Line ordering within the device dictionary is irrelevant, although it is common to put the extends line first when storing the dictionary as a file.

The template itself lives in:

/etc/lava-server/dispatcher-config/device-types/qemu.jinja2

This dictionary does not include a setting to use a tap device which means that this device would not support a hacking session inside the virtual machine. Setting up a bridge is out of scope for this documentation.

See also

Creating a device dictionary for the device to export and modify a device dictionary, Updating a device dictionary to import a device dictionary into the database for use with a new or existing device, Checking your templates for help with types of devices other than QEMU and Device type templates for help with how the device dictionary works with the device-type templates.

Once updated, the device dictionary is added to the Device view in the administrative interface under the Advanced Properties section at the base of the page.

Adding other devices of known device-types

The core principles remain the same as for QEMU, the main differences are in the way that the device dictionary is needed to provide a wider range of settings covering power control, serial connections, network details and other values.

See also

Writing Health Checks for devices - each time a new device type is added to an instance, a health check test job needs to be defined.

Check existing instances

Templates usually exist for known device types because an existing instance is using the template. Often, that instance will be Linaro’s central validation lab in Cambridge which is accessible via https://validation.linaro.org/ .

The contents of the device dictionary for particular devices are visible to anyone with access to that device type, using the device detail page. Details of the jinja2 files used to update the device dictionary on Linaro instances is also held in git:

https://git.linaro.org/lava/lava-lab.git

The structure of the device dictionary files will be similar for each device of the same type but the values will change. An example for a beaglebone-black device looks like:

{% extends 'beaglebone-black.jinja2' %}
{% set connection_command = 'telnet localhost 7101' %}
{% set hard_reset_command = '/usr/local/lab-scripts/snmp_pdu_control --hostname pdu15 --command reboot --port 11' %}
{% set power_off_command = '/usr/local/lab-scripts/snmp_pdu_control --hostname pdu15 --command off --port 11' %}
{% set power_on_command = '/usr/local/lab-scripts/snmp_pdu_control --hostname pdu15 --command on --port 11' %}

https://git.linaro.org/lava/lava-lab.git/tree/staging.validation.linaro.org/lava/pipeline/devices/staging-black01.jinja2

Note

It is recommended to keep the device dictionary jinja files under version control. The templates are configuration files, so if you modify the default templates, those need to be under version control as well.