swift-storage improvements: use local devices and avoid loopback storage

[Adam Sheridan]

when deploying the swift proxy charm and adding the relation you get an error saying about not enough storage zones. This is because the config of swift-storage is set to use block-device: sdc but the physical machines only have 2 disks, so have no sdc.

The answer is to tell config to use "/swift-storage-image.img|10G" this will create a 10 gb file on root of the machine and create a loopback device and attach swift-storage to it.

[Ryan Beisner (1chb1n)]

This is expected behavior. The doc-fix that I would suggest here is to advise the reader that they may need to adjust block device config to match their own hardware/topology.

[Ryan Beisner (1chb1n)]

Further: the local loopback file approach is not recommended for production use cases. The loopback approach is handy for testing. The documentation should be clarified to represent these 2 points. Thank you.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/693745

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/693745
Committed: https://git.openstack.org/cgit/openstack/charm-deployment-guide/commit/?id=6928d6ac987fac8a7f519ce546fc6e0b3da4080c
Submitter: Zuul
Branch: master

commit 6928d6ac987fac8a7f519ce546fc6e0b3da4080c
Author: Peter Matulis <email address hidden>
Date: Mon Nov 11 14:56:39 2019 -0500

    Use local devices and avoid loopback storage

    Closes-Bug: #1777683

    Change-Id: Ia35e962f7a536ca092c3eb5ebce258e1a37d3ab2