yahoo-eng-team team mailing list archive

[Dharini Chandrasekar <dharini.chandrasekar@xxxxxxxxx>]

Public bug reported:

When using Content-Range for a partial download of an image with image caching enabled,
the partial download fails due to a cache error as in [0]

This is because, the downloaded image is also getting cached using tee-
iter in image_cache/__init__.py. Here there is a check for the images
checksum and the download's checksum. With partial download, there is a
mismatch of the full image checksum and the partial image checksum
resulting in a 500.

Steps to reproduce:

1. Create an image
glance image-create --name test1 --visibility public --container-format bare --disk-format qcow2 < /home/stack/devstack/local.conf 

2. Verify image creation and run the script to do a partial download.

2.a. glance image-list
+--------------------------------------+---------------------------------+
| ID                                   | Name                            |
+--------------------------------------+---------------------------------+
| a3e38525-ad23-4ccb-9641-841f432ecf4a | cirros-0.3.4-x86_64-uec         |
| b3d0a0b6-5082-4250-a3d2-951992343a6e | cirros-0.3.4-x86_64-uec-kernel  |
| d123b95a-b00a-4db9-891b-a965c254581b | cirros-0.3.4-x86_64-uec-ramdisk |
| 59c7e82a-6150-46b6-b19f-b93396bd5d8b | test1                           |
+--------------------------------------+---------------------------------+

2.b. Execute the script that will request for a partial download of the
above created image. [1]

Fails with a 500. Traceback is as here: [2]

The full download goes through successfully though. [3]

[0] https://github.com/openstack/glance/blob/master/glance/image_cache/__init__.py#L360-L364
[1] http://paste.openstack.org/show/598886/
[2] http://paste.openstack.org/show/598881/
[3] http://paste.openstack.org/show/598887/

We need to educate cache here about a partial download to prevent this.

** Affects: glance
     Importance: Undecided
     Assignee: Dharini Chandrasekar (dharini-chandrasekar)
         Status: New

** Changed in: glance
     Assignee: (unassigned) => Dharini Chandrasekar (dharini-chandrasekar)

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https://bugs.launchpad.net/bugs/1664709

Title:
  Partial download of image fails when using  image caching

Status in Glance:
  New

Bug description:
  When using Content-Range for a partial download of an image with image caching enabled,
  the partial download fails due to a cache error as in [0]

  This is because, the downloaded image is also getting cached using
  tee-iter in image_cache/__init__.py. Here there is a check for the
  images checksum and the download's checksum. With partial download,
  there is a mismatch of the full image checksum and the partial image
  checksum resulting in a 500.

  Steps to reproduce:

  1. Create an image
  glance image-create --name test1 --visibility public --container-format bare --disk-format qcow2 < /home/stack/devstack/local.conf 

  2. Verify image creation and run the script to do a partial download.

  2.a. glance image-list
  +--------------------------------------+---------------------------------+
  | ID                                   | Name                            |
  +--------------------------------------+---------------------------------+
  | a3e38525-ad23-4ccb-9641-841f432ecf4a | cirros-0.3.4-x86_64-uec         |
  | b3d0a0b6-5082-4250-a3d2-951992343a6e | cirros-0.3.4-x86_64-uec-kernel  |
  | d123b95a-b00a-4db9-891b-a965c254581b | cirros-0.3.4-x86_64-uec-ramdisk |
  | 59c7e82a-6150-46b6-b19f-b93396bd5d8b | test1                           |
  +--------------------------------------+---------------------------------+

  2.b. Execute the script that will request for a partial download of
  the above created image. [1]

  Fails with a 500. Traceback is as here: [2]

  The full download goes through successfully though. [3]

  [0] https://github.com/openstack/glance/blob/master/glance/image_cache/__init__.py#L360-L364
  [1] http://paste.openstack.org/show/598886/
  [2] http://paste.openstack.org/show/598881/
  [3] http://paste.openstack.org/show/598887/

  We need to educate cache here about a partial download to prevent
  this.

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