Understanding PXE Boot Behaviour for Newly Added Machines with Existing OS

Users
1

Hello,

I’m working with MAAS 3.5.x (deb packages) and seeking clarification on its initial boot behaviour.

Consider a machine with a boot order of:

  1. OS Drive
  2. NIC (PXE)

If this machine is added to MAAS using maas admin machine create, does MAAS automatically initiate a PXE boot for commissioning/enlistment?

Furthermore, what is the expected behaviour if the machine’s OS drive already contains an operating system? Will the machine attempt to boot from the OS drive first and bypass PXE, or will MAAS’s PXE boot attempt still occur and potentially fail or lead to unexpected behaviour given the local OS?

Any detailed explanation of this interaction would be greatly appreciated.

thanks!

2

Hi @trsoumi88

Consider a machine with a boot order of:

  1. OS Drive
  2. NIC (PXE)

If this machine is added to MAAS using maas admin machine create, does MAAS automatically initiate a PXE boot for commissioning/enlistment?

If machine doesn’t do PXE, but rather boot from disk, then MAAS cannot do much with this machine. However you can still do power management (if you configure power parameters)

MAAS requires machine to have PXE as the first boot option.

3

My rule of thumb is to set first boot device as pxe then disk. We move servers around to different racks/subnets and this makes it convenient. Not sure what platform you’re using, but I would check out if there is redfish support and create a commissioning script to set this.

4

If you use redfish you don’t need a custom commissioning script: MAAS will instruct the machine to PXE boot when it performs power commands

5

At the moment we make use of IPMI. We may plan using Redfish for any new machines.

If you use redfish you don’t need a custom commissioning script: MAAS will instruct the machine to PXE boot when it performs power commands

@r00ta, is this the same behaviour for IPMI?

6

If you specify all the power parameters for IPMI when you call maas admin machines create yes, the machine should be instructed by MAAS to PXE.

Instead, if you just enlist the machine (meaning you simply power on the machine and you want MAAS to automatically discover it, then you must instruct the machine to PXE manually first)

7

Sweet!

We use the MaaS API/ Python client to manage machine creation and deployment. When we create a machine, we provide its IPMI authentication and MAC address. This would mean, MaaS will instruct PXE boot irrespective of the Boot order. .

Our standard procedure for a subset of machines involves installing the operating system with MaaS. Following a successful installation, we delete the machine’s details from MaaS inventory and disable IPMI completely. This helps us prevent unwanted PXE boots, as we actively avoid prioritising PXE in the boot order to reduce associated risks.

thanks!

8

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