[nova] [cinder] [ceph] Questioning deployment choices
Hi Fellow OpenStackers! I have a question regarding nova-cinder-ceph deployment configuration. Most notably ephemeral storage. So - if I configure Nova to use Ceph as ephemeral storage and Cinder's only backend is Ceph as well then how does ephemeral storage differ from persistent storage now except for interface from Cinder rather than Nova (and all that comes with that) and a different pool? Was Nova's Ceph integration added just to be able to avoid Cinder in certain scenarios? Other Cinder backends did not get support from Nova. Looking forward to your insights. -yoctozepto
On 20-04-20 11:51:52, Radosław Piliszek wrote:
Hi Fellow OpenStackers!
I have a question regarding nova-cinder-ceph deployment configuration. Most notably ephemeral storage.
So - if I configure Nova to use Ceph as ephemeral storage and Cinder's only backend is Ceph as well then how does ephemeral storage differ from persistent storage now except for interface from Cinder rather than Nova (and all that comes with that) and a different pool? Was Nova's Ceph integration added just to be able to avoid Cinder in certain scenarios?
The original change introducing support suggests this was due to Nova not supporting booting from volumes in 2013? Add RBD supporting to libvirt for creating local volume https://review.opendev.org/#/c/36042/
Other Cinder backends did not get support from Nova.
Yeah as since I've worked on Nova we've mostly pushed devs and users to Cinder for any additional exotic storage backend support. Cheers, -- Lee Yarwood A5D1 9385 88CB 7E5F BE64 6618 BCA6 6E33 F672 2D76
On Tue, Apr 21, 2020 at 4:54 PM Lee Yarwood <lyarwood@redhat.com> wrote:
The original change introducing support suggests this was due to Nova not supporting booting from volumes in 2013?
Add RBD supporting to libvirt for creating local volume https://review.opendev.org/#/c/36042/
Thanks, seems I was afraid to dig that deep (or really git did not want me to). :-) That explains a lot.
Other Cinder backends did not get support from Nova.
Yeah as since I've worked on Nova we've mostly pushed devs and users to Cinder for any additional exotic storage backend support.
Thank you, all clear. -yoctozepto
Regarding the subject, I also found this: https://blueprints.launchpad.net/nova/+spec/nova-ephemeral-cinder bp: Nova using ephemeral storage with cinder (from 2014-04-30, recurring 2017-04-18; not implemented) -yoctozepto
On Wed, Apr 22, 2020 at 9:32 AM Radosław Piliszek <radoslaw.piliszek@gmail.com> wrote:
Regarding the subject, I also found this: https://blueprints.launchpad.net/nova/+spec/nova-ephemeral-cinder bp: Nova using ephemeral storage with cinder (from 2014-04-30, recurring 2017-04-18; not implemented)
-yoctozepto
Also, the change referenced by Lee, introducing RBD support into Nova, was part of: https://blueprints.launchpad.net/nova/+spec/bring-rbd-support-libvirt-images... which, based on extensive discussion there, looks like handicapped approach at that other bp. So, essentially, boot-from-volume existed but there was demand for no-Cinder-interactions and Ceph was a popular choice. -yoctozepto
Hello, I know that [1] has been something requested by operators before, including myself, but there hasn't been any resources available to perform the work :( Since there is a lot of ways you can get "locked in" when using the RBD image backend with Nova [2]. Best regards [1] https://blueprints.launchpad.net/nova/+spec/nova-ephemeral-cinder [2] Referring to for example Magnum, Octavia etc (For Octavia that is not the case today as they support volume-backed instances now). ________________________________________ From: Radosław Piliszek <radoslaw.piliszek@gmail.com> Sent: Wednesday, April 22, 2020 9:57 AM To: openstack-discuss Subject: Re: [nova] [cinder] [ceph] Questioning deployment choices On Wed, Apr 22, 2020 at 9:32 AM Radosław Piliszek <radoslaw.piliszek@gmail.com> wrote:
Regarding the subject, I also found this: https://blueprints.launchpad.net/nova/+spec/nova-ephemeral-cinder bp: Nova using ephemeral storage with cinder (from 2014-04-30, recurring 2017-04-18; not implemented)
-yoctozepto
Also, the change referenced by Lee, introducing RBD support into Nova, was part of: https://blueprints.launchpad.net/nova/+spec/bring-rbd-support-libvirt-images... which, based on extensive discussion there, looks like handicapped approach at that other bp. So, essentially, boot-from-volume existed but there was demand for no-Cinder-interactions and Ceph was a popular choice. -yoctozepto
participants (3)
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Lee Yarwood
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Radosław Piliszek
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Tobias Urdin