[openstack-dev] [TripleO] [diskimage-builder] LVM in diskimage-builder

Gregory Haynes greg at greghaynes.net
Wed May 18 14:52:56 UTC 2016


On Tue, May 17, 2016, at 02:32 PM, Andre Florath wrote:
> Hi All!
> 
> AFAIK the diskimage-builder started as a testing tool, but it looks
> that it evolves more and more into a general propose tool for creating
> docker and VM disk images.
> 
> Currently there are ongoing efforts to add LVM [1]. But because some
> features that I need are missing, I created my own prototype to get a
> 'feeling' for the complexity and a possible way doing things [2]. I
> contacted Yolanda (the author of the original patch) and we agreed to
> join forces here to implement a patch that fits our both needs.
> 

Glad to hear this. I'd recommend first making sure the public interfaces
defined in[1] don't conflict with the features you'd like to add (or
even potentially like to add). AFAICT this only matters for the LVM
config passed in via DIB_LVM_SETTINGS. The other features should be
doable in a follow on patch without breaking backwards compatibility and
this is probably the best path forward (rather than adding them in to
[1]). Obviously, if there's any other potentially conflicting public
interfaces I am missing we should fix those before [1] goes in.

As for the DIB_LVM_SETTINGS variable - I don't entirely understand the
issues being raised but we can continue that conversation on [1] since
it is a lot easier to discuss there.

> Yolanda made the proposal before starting implementing things, we
> could contact Open Stack developers via this mailing list and ask
> about possible additional requirements and comments.
> 
> Here is a short list of my requirements - and as far as I understood
> Yolanda, her requirements are a subset:
> 
> MUST be able to
> o use one partition as PV
> o use one VG
> o use many LV (up to 10)
> o specify the mount point for each of the LVs
> o specify mount points that 'overlap', e.g.
>   /, /var, /var/log, /var/spool
> o use the default file system (options) as specified via command line
> o survive in every day's live - and not only in dedicated test
>   environment: must be robust and handle error scenarios
> o use '/' (root fs) as LV
> o run within different distributions - like Debian, Ubuntu, Centos7.
> 
> NICE TO HAVE
> o Multiple partitions as PVs
> o Multiple VGs
> o LVM without any partition
>   Or: why do we need partitions these days? ;-)
>   Problem: I have no idea how to boot from a pure LVM image.
> 
> Every idea or comment will help!  Please feel invited to have a
> (short) look / review at the implementation [1] and the design study
> [2].
> 
> Kind regards
> 
> Andre


Thanks,
Greg



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