ironic/doc/source/install/enabling-drivers.rst

Enabling drivers and hardware types

Introduction

The Bare Metal service delegates actual hardware management to drivers. Starting with the Ocata release, two types of drivers are supported: classic drivers (for example, pxe_ipmitool, agent_ilo, etc.) and the newer hardware types (for example, generic redfish and ipmi or vendor-specific ilo and irmc).

Drivers, in turn, consist of hardware interfaces: sets of functionality dealing with some aspect of bare metal provisioning in a vendor-specific way. Classic drivers have all hardware interfaces hardcoded, while hardware types only declare which hardware interfaces they are compatible with.

Please refer to the driver composition reform specification for technical details behind hardware types.

From API user's point of view, both classic drivers and hardware types can be assigned to the driver field of a node. However, they are configured differently.

Enabling hardware types

Hardware types are enabled in the configuration file of the ironic-conductor service by setting the enabled_hardware_types configuration option, for example:

[DEFAULT]
enabled_hardware_types = ipmi,redfish

Due to the driver's dynamic nature, they also require configuring enabled hardware interfaces.

Note

All available hardware types and interfaces are listed in setup.cfg file in the source code tree.

Enabling hardware interfaces

There are several types of hardware interfaces:

boot

manages booting of both the deploy ramdisk and the user instances on the bare metal node. See /admin/interfaces/boot for details.

Boot interface implementations are often vendor specific, and can be enabled via the enabled_boot_interfaces option:

[DEFAULT]
enabled_hardware_types = ipmi,ilo
enabled_boot_interfaces = pxe,ilo-virtual-media

Boot interfaces with pxe in their name require configure-pxe. There are also a few hardware-specific boot interfaces - see /admin/drivers for their required configuration.

console

manages access to the serial console of a bare metal node. See /admin/console for details.

deploy

defines how the image gets transferred to the target disk. See /admin/interfaces/deploy for an explanation of the difference between supported deploy interfaces direct and iscsi.

The deploy interfaces can be enabled as follows:

[DEFAULT]
enabled_hardware_types = ipmi,redfish
enabled_deploy_interfaces = iscsi,direct

Additionally,

• the iscsi deploy interface requires configure-iscsi
• the direct deploy interface requires the Object Storage service or an HTTP service

inspect

implements fetching hardware information from nodes. Can be implemented out-of-band (via contacting the node's BMC) or in-band (via booting a ramdisk on a node). The latter implementation is called inspector and uses a separate service called ironic-inspector. Example:

[DEFAULT]
enabled_hardware_types = ipmi,ilo,irmc
enabled_inspect_interfaces = ilo,irmc,inspector

See /admin/inspection for more details.

management

provides additional hardware management actions, like getting or setting boot devices. This interface is usually vendor-specific, and its name often matches the name of the hardware type (with ipmitool being a notable exception). For example:

[DEFAULT]
enabled_hardware_types = ipmi,redfish,ilo,irmc
enabled_management_interfaces = ipmitool,redfish,ilo,irmc

Using ipmitool requires configure-ipmi. See /admin/drivers for the required configuration of each driver.

network

connects/disconnects bare metal nodes to/from virtual networks. This is the only interface that is also pluggable for classic drivers. See configure-tenant-networks for more details.

power

runs power actions on nodes. Similar to the management interface, it is usually vendor-specific, and its name often matches the name of the hardware type (with ipmitool being again an exception). For example:

[DEFAULT]
enabled_hardware_types = ipmi,redfish,ilo,irmc
enabled_power_interfaces = ipmitool,redfish,ilo,irmc

Using ipmitool requires configure-ipmi. See /admin/drivers for the required configuration of each driver.

raid

manages building and tearing down RAID on nodes. Similar to inspection, it can be implemented either out-of-band or in-band (via agent implementation). See /admin/raid for details. For example:

[DEFAULT]
enabled_hardware_types = ipmi,redfish,ilo,irmc
enabled_raid_interfaces = agent,no-raid

storage

manages the interaction with a remote storage subsystem, such as the Block Storage service, and helps facilitate booting from a remote volume. This interface ensures that volume target and connector information is updated during the lifetime of a deployed instance. See /admin/boot-from-volume for more details.

This interface defaults to a noop driver as it is considered an "opt-in" interface which requires additional configuration by the operator to be usable.

For example:

[DEFAULT]
enabled_hardware_types = ipmi,irmc
enabled_storage_interfaces = cinder,noop

vendor

is a place for vendor extensions to be exposed in API. See /contributor/vendor-passthru for details.

[DEFAULT]
enabled_hardware_types = ipmi,redfish,ilo,irmc
enabled_vendor_interfaces = ipmitool,no-vendor

Here is a complete configuration example, enabling two generic protocols, IPMI and Redfish, with a few additional features:

[DEFAULT]
enabled_hardware_types = ipmi,redfish
enabled_boot_interfaces = pxe
enabled_console_interfaces = ipmitool-socat,no-console
enabled_deploy_interfaces = iscsi,direct
enabled_inspect_interfaces = inspector
enabled_management_interfaces = ipmitool,redfish
enabled_network_interfaces = flat,neutron
enabled_power_interfaces = ipmitool,redfish
enabled_raid_interfaces = agent
enabled_storage_interfaces = cinder,noop
enabled_vendor_interfaces = ipmitool,no-vendor

Note that some interfaces have implementations named no-<TYPE> where <TYPE> is the interface type. These implementations do nothing and return errors when used from API.

Hardware interfaces in multi-conductor environments

When enabling hardware types and their interfaces, make sure that for every enabled hardware type, the whole set of enabled interfaces matches for all conductors. However, different conductors can have different hardware types enabled.

For example, you can have two conductors with the following configuration respectively:

[DEFAULT]
enabled_hardware_types = ipmi
enabled_deploy_interfaces = direct
enabled_power_interfaces = ipmitool
enabled_management_interfaces = ipmitool

[DEFAULT]
enabled_hardware_types = redfish
enabled_deploy_interfaces = iscsi
enabled_power_interfaces = redfish
enabled_management_interfaces = redfish

But you cannot have two conductors with the following configuration respectively:

[DEFAULT]
enabled_hardware_types = ipmi,redfish
enabled_deploy_interfaces = direct
enabled_power_interfaces = ipmitool,redfish
enabled_management_interfaces = ipmitool,redfish

[DEFAULT]
enabled_hardware_types = redfish
enabled_deploy_interfaces = iscsi
enabled_power_interfaces = redfish
enabled_management_interfaces = redfish

This is because the redfish hardware type will have different enabled deploy interfaces on these conductors. It would have been fine, if the second conductor had enabled_deploy_interfaces = direct instead of iscsi.

This situation is not detected by the Bare Metal service, but it can cause inconsistent behavior in the API, when node functionality will depend on which conductor it gets assigned to.

Note

We don't treat this as an error, because such temporary inconsistency is inevitable during a rolling upgrade or a configuration update.

Configuring interface defaults

When an operator does not provide an explicit value for one of the interfaces (when creating a node or updating its driver), the default value is calculated as described in hardware_interfaces_defaults. It is also possible to override the defaults for any interfaces by setting one of the options named default_<IFACE>_interface, where <IFACE> is the interface name. For example:

[DEFAULT]
default_deploy_interface = direct
default_network_interface = neutron

This configuration forces the default deploy interface to be direct and the default network interface to be neutron for all hardware types.

The defaults are calculated and set on a node when creating it or updating its hardware type. Thus, changing these configuration options has no effect on existing nodes.

Warning

The default interface implementation must be configured the same way across all conductors in the cloud, except maybe for a short period of time during an upgrade or configuration update. Otherwise the default implementation will depend on which conductor handles which node, and this mapping is not predictable or even persistent.

Warning

These options should be used with care. If a hardware type does not support the provided default implementation, its users will have to always provide an explicit value for this interface when creating a node.

Enabling classic drivers

Classic drivers are enabled in the configuration file of the ironic-conductor service by setting the enabled_drivers configuration option, for example:

[DEFAULT]
enabled_drivers = pxe_ipmitool,pxe_ilo,pxe_drac

The names in this comma-separated list are entry point names of the drivers. They have to be available at conductor start-up, and all dependencies must be installed locally. For example,

• drivers starting with pxe and some drivers starting with agent require configure-pxe,
• drivers starting with pxe or having iscsi in their name require configure-iscsi,
• drivers ending with ipmitool require configure-ipmi.

See /admin/drivers for the required configuration of each driver.