WIP: HALON-894: Support multiple storage services on a single node

Seagate / halon

High availability solution

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WIP: HALON-894: Support multiple storage services on a single node #1570

Closed mssawant closed 5 years ago

mssawant commented 5 years ago

Modify h0fabricate to generate halon_facts file with new format changes.
Add code changes to mero-halon test.
Add M0Device collection in M0Service.
Remove M0Device collection from M0Host.
Make relevant code changes.
Add Debug.Trace messages.

vvv commented 5 years ago

closed

vvv commented 5 years ago

This merge request has been obsoleted by http://gitlab.mero.colo.seagate.com/mero/halon/merge_requests/1573. It may be reopened if necessary.

vvv commented 5 years ago

added 1 commit

9ceee253 - [WIP] Rename the RFC file

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mssawant commented 5 years ago

I can try first option. Regarding second option, I think the main idea to have drives attached to specific services (ios, be, addb) in facts file is for Halon to distinguish between multiple storage services on the same node. Because we cannot have multiple hostnames for the same physical node which relates to m0_fqdn, I though we should be able to specify multiple storage roles for the same physical node or for the same m0_fqdn. With my earlier format proposal, we can add multiple storage entries with corresponding devices for the same.

vvv commented 5 years ago

added 1 commit

cc19d1d9 - scripts/h0fabricate: Bugfix and minor refactoring

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vvv commented 5 years ago

Currently a “role” is merely a reference to roles file entry. Simple. Putting services and devices information into a role descriptor complicates the format. This complication is avoidable:

The RFC proposes to keep services information (m0h_services) at the top of server descriptor. No changes in roles processing are required.
Another approach is to mark each drive with the corresponding service type — to add id_m0_servers/%/m0h_devices/%/service_type field (supported values: "ios", "be", "addb"). The facts file format remains pretty much the same in this case, required amount of code changes is minimal.

When deciding which approach to choose, we should also take the effort of m0genfacts modification into consideration.

vvv commented 5 years ago

@mandar.sawant I've added a draft of the RFC — rfc/026-XXX.md. If we agree that such document is needed, we should ~~rename the file and~~ take care of the sections marked with "XXX".

vvv commented 5 years ago

added 1 commit

eae5d436 - rfc: Add draft of RFC document

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vvv commented 5 years ago

The source branch is 70 commits behind the target branch
$ git log --oneline origin/Halon-894..origin/master | wc -l
70
The branch is quite old. Why?