On 12/06/2025 22:16, Barrera, Eric wrote:
I've done OS install by booting to install iso but add a disk to the VM, install to disk, then create image from volume or snapshot or something like that I could use as an image.
ya so here are the options nova allows you to boot form an existing image in glance, that image can be a root disk image, an iso, or separate images containing a kernel + ram disk + filesystem https://docs.openstack.org/nova/latest/user/launch-instances.html https://docs.openstack.org/nova/latest/user/launch-instance-using-ISO-image.... that is the primary way of create a server. the next option is to boot form a cinder volume. you can precreate the volume with the root files system or you can ask nova to do that from a glance image. https://docs.openstack.org/nova/latest/user/launch-instance-from-volume.html the third option is a variation of the first two. you can create a "empty" image that just has a a valid gpt partion table. in the case of a volume you can create a blank volume directly. this will result in a server that cannot boot to an os but will start and error in the bios. at this point you have 3 sub options 1 you can use rescure with an iso and manually do an install https://docs.openstack.org/nova/latest/user/rescue.html 2 if you add metadta to your neutorn network you can use the ipxe booth functionaltiy that they supprot for ironic by using an ipxe rescure imagne https://docs.openstack.org/nova/latest/user/boot-instance-using-PXE.html 3 if the blank image/volume has the correct image properites you can enable the vms boot menue and access the ipxe capablites build into the uefi enviornment to install. to do this you need to set hw_boot_menu=true in the image or hw:boot_menu=true in the flavor. your 4th option is to booth form a blank cinder voluem and attch a second cinder volume with your install media. https://docs.openstack.org/nova/latest/user/block-device-mapping.html#block-... this is mujch more complex but you can ask nova to create a service rwith a black local or cinder root disk. you can also create a secon cinder volume and attach it as a cdrom form na iso in glance nad use that to install form by usign the boot index atribute on the block device mappigns we do not have docs for this as doing it that way is very complex and even core reviers will get this wrong first tiem. its just too erro prone to do and we dont test it. nova does not directly support virutal media like you might have in some vituraliation enviomnents nor does it offically supprot pxe booting but it is possible to do.
Internal Use - Confidential -----Original Message----- From: Jeremy Stanley <fungi@yuggoth.org> Sent: Thursday, June 12, 2025 9:45 AM To: openstack-discuss@lists.openstack.org Subject: Re: [dev][ops][nova] OpenStack Templateless Provisioning
On 2025-06-12 13:57:17 -0000 (-0000), prmjh4@gmail.com wrote: [...]
It always asked me to pass a template image in order to create the server without the template image it does not allow me to create a server. [...]
Okay, I didn't understand what you meant by "template" in your first message, since in OpenStack we refer to "images" for what you seem to be talking about.
No, as far as I know there is no way to create a server instance without the cloud provider or the user supplying a disk image to boot from. In the case of most OpenStack clouds, the operator of the cloud environment includes a catalogue of generic images for different operating systems and you would select one of those to boot as the initial state of the server. If there are none or the available options aren't suitable, the user can typically upload an image (these are most often in qcow2 or raw disk format, like the ones offered as "cloud image" downloads by may GNU/Linux distributions). It's also possible to use a tool like diskimage-builder to create or customize an image of your own and then upload that.
I guess what you're hoping for is a way to boot a server instance with an empty disk and then run some sort of interactive operating system installer through the server's remote console? I'm not aware of any options for that... maybe there's a trick someone else knows?
I've added the [ops] and [nova] subject tags in hopes of drawing broader attention to your question, since [dev] is mostly used for discussions about developing OpenStack itself, not developing other software that interacts with OpenStack interfaces or resources. -- Jeremy Stanley