754f15c92d
Apparently, this was missed when the new options were introduced. Story: #2004846 Change-Id: I04be5a5a8fa962bafa68f0ea93ee127b1610c20f
3.2 KiB
Boot interfaces
The boot interface manages booting of both the deploy ramdisk and the user instances on the bare metal node.
The PXE boot interface is generic and works
with all hardware that supports booting from network. Alternatively,
several vendors provide virtual media implementations of the
boot interface. They work by pushing an ISO image to the node's management
controller, and do not require either PXE or iPXE. Check your driver
documentation at ../drivers for details.
PXE boot
The pxe boot interface uses PXE
or iPXE to deliver the
target kernel/ramdisk pair. PXE uses relatively slow and unreliable TFTP
protocol for transfer, while iPXE uses HTTP. The downside of iPXE is
that it's less common, and usually requires bootstrapping using PXE
first.
The pxe boot interface works by preparing a PXE/iPXE
environment for a node on the file system, then instructing the DHCP
provider (for example, the Networking service) to boot the node from it.
See ref:direct-deploy-example for a
better understanding of the whole deployment process.
Note
Both PXE and iPXE are configured differently, when UEFI boot is used instead of conventional BIOS boot. This is particularly important for CPU architectures that do not have BIOS support at all.
The pxe boot interface is used by default for many
hardware types, including ipmi. Some hardware types,
notably ilo and irmc have their specific
implementations of the PXE boot interface.
Additional configuration is required for this boot interface - see
/install/configure-pxe
for details.
Common options
Enable persistent boot device for deploy/clean operation
For (i)PXE booting, Ironic uses non-persistent boot order changes for clean/deploy by default. For some drivers, persistent changes are far more costly than non-persisent ones, so this approach can bring a performance benefit.
In order to control this behavior, however, Ironic provides the
force_persistent_boot_device flag in the node's
driver_info. It allows the values Default
(make all changes but the last one upon deployment non-persistent),
Always (make all changes persistent), and
Never (make all boot order changes non-persistent). For
example in order to have only persistent changes one would need to set
something like:
$ openstack baremetal node set --driver-info force_persistent_boot_device='Always' <node>Note
It is recommended to check if the node's state has not changed as there is no way of locking the node between these commands.
Note
The values 'True'/'False' for the option 'force_persistent_boot_device' in the node's driver info for the (i)PXE drivers are deprecated and support for them may be removed in a future release. The former default value 'False' is replaced by the new value 'Default', the value 'True' is replaced by 'Always'.