This patch adds a new environment variable, CINDER_BACKUP_DRIVER for
configuring cinder backup driver used when c-bak service is enabled.
This gets cinder backup driver configurable with a similar pattern to
cinder backends. Although the current configurable backup drivers don't
need cleanup functions, the interface for cleanup is prepared for the
future.
The following backup drivers can be configured:
swift:
This is the default backup driver.
ceph:
This already can be configured if ceph backend driver is enabled. For
backward compatibility, ceph backup driver is used if ceph backend
driver is enabled and no backup driver is specified.
s3_swift:
The s3 backup driver gets configurable with this patch. By specifying
's3_swift', the driver is configured for swift s3api.
In the future, lib/cinder_backups/s3 should be created separatedly for
external S3 compatible storage. This file will just set given parameters
such as a URL and credentials.
Change-Id: I356c224d938e1aa59c8589387a03682b3ec6e23d