Bug 1733616

Summary:	[RFE] Add role to create LVMs for bluestore in advance of the ceph-osd role
Product:	[Red Hat Storage] Red Hat Ceph Storage	Reporter:	John Fulton <johfulto>
Component:	Ceph-Ansible	Assignee:	Guillaume Abrioux <gabrioux>
Status:	CLOSED WONTFIX	QA Contact:	Vasishta <vashastr>
Severity:	low	Docs Contact:
Priority:	low
Version:	4.0	CC:	aschoen, ceph-eng-bugs, gfidente, gmeno, mamccoma, mhackett, mmuench, nthomas
Target Milestone:	rc	Keywords:	FutureFeature
Target Release:	5.*
Hardware:	Unspecified
OS:	Unspecified
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Last Closed:	2020-03-23 16:11:01 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description John Fulton 2019-07-26 19:01:19 UTC

It's easy to deploy bluestore with optimal disk configuration when the following is syntax is used HDDs are mixed with NVMes.

osd_objectstore: bluestore
osd_scenario: lvm
devices:
  - /dev/sda
  - /dev/sdb
  - /dev/nvme0n1
  - /dev/sdc
  - /dev/sdd
  - /dev/nvme1n1

ceph-volume does a great job of automating this case because it can differentiate between HDD (/dev/sda) and SSD (/dev/nvme0n1) and will configure bluestore DB devices on the SSDs.

However, in a configuration where /dev/sda is an SSD (e.g. perhaps a SATA SSD), e.g. bug 1732915, then the NVMe SSDs are used as OSDs, not as bluestore DB devices. If the customer wants the SATA SSDs to be OSDs and the NVMe SSDs to be bluestore DB devices, then the customer needs to create the LVMs in advance and then pass ceph-ansible not a devices list but an lvm_volumes list like this:

    lvm_volumes:
        - data: ceph_lv0_data
          data_vg: ceph_vg0
          db: ceph_lv0_db
          db_vg: ceph_vg_fast0
        ...

The process to create the lvm_volumes in advance is error prone. We can provide customers scripts to do this but it would be a much better customer experience if ceph-ansible had a role to create the LVMs in advance.

Comment 2 John Fulton 2019-07-31 14:08:28 UTC

It looks like we can use this playbook:

 https://github.com/ceph/ceph-ansible/blob/v3.2.21/infrastructure-playbooks/lv-create.yml

To solve a lot, if not all, of the problem raised by this bug. Next step is probably to experiment with the above.

Comment 3 Giridhar Ramaraju 2019-08-05 13:10:47 UTC

Updating the QA Contact to a Hemant. Hemant will be rerouting them to the appropriate QE Associate. 

Regards,
Giri

Comment 4 Giridhar Ramaraju 2019-08-05 13:11:49 UTC

Updating the QA Contact to a Hemant. Hemant will be rerouting them to the appropriate QE Associate. 

Regards,
Giri