Re: [libvirt] [PATCH 4/4] kbase: Add document outlining backing chain XML config and troubleshooting

On 12/17/19 12:35 PM, Peter Krempa wrote: > Signed-off-by: Peter Krempa <pkrempa(a)redhat.com&gt; > ---

> +If the ``backing file format:`` field is missing above the format was not > +specified properly. The image can be fixed by the following command: > + > +:: > + > + qemu-img rebase -f $IMAGE_FORMAT -F $BACKING_IMAGE_FORMAT -b $BACKING_IMAGE_PATH $IMAGE_PATH Adding -u can make this operation faster (blindly update the image metadata, rather than actually crawling the entire image to perform a data operation in the process). But I'm not sure whether we want to document that here.

> +It is important to fill out ``$BACKING_IMAGE_FORMAT`` and ``$IMAGE_FORMAT`` > +properly. ``$BACKING_IMAGE_PATH`` should be specified as a full absolute path. > +If relative referencing of the backing image is desired, the path must be > +relative to the location of image described by ``$IMAGE_PATH``. > + > +Missing images reported after after moving disk images into a different path > +---------------------------------------------------------------------------- > + > +The path to the backing image which is recorded in the image metadata often > +contains a full path to the backing image. This is the default libvirt-created > +image configuration. When such images are moved to a different location the > +top image will no longer point to the correct image. > + > +To fix such issue you can either fully specify the image chain in the domain XML > +as pointed out above or the following ``qemu-img`` command can be used: > + > +:: > + > + qemu-img rebase -u -f $IMAGE_FORMAT -F $BACKING_IMAGE_FORMAT -b $BACKING_IMAGE_PATH $IMAGE_PATH > + Odd to mention -u here but not above. Should we be consistent between the two examples?