Methods and systems for patching multiple disk images derived from a common base disk image

• US 8,464,241 B2
• Filed: 05/19/2009
• Issued: 06/11/2013
• Est. Priority Date: 05/20/2008
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Hayton, Richard
• Primary Examiner(s): Zhen, Li B
• Assistant Examiner(s): Kia, Arshia S
• Application Number:
  US12/468,408
• Publication Number:
  US 20090292737A1
• Time in Patent Office: 1,484 Days
• Field of Search: 717/170
• US Class Current: 717/170
• CPC Class Codes: G06F 8/63 Image based installation; Cloning; Build to order
• CPC Class Codes: G06F 8/658 Incremental updates; Differential updates

Abstract

A method for updating a plurality of disk images, each of the plurality of disk images derived from a common base disk image and a delta image comprising a plurality of delta files, includes applying a delta file to a base disk image to generate a second disk image comprising a portion of the base disk image modified by the delta file and an unmodified portion of the base disk image. Each delta file represents at least one difference between one of the plurality of user disk images and the base disk image. The method includes applying a patch to a copy of the base disk image, and determining that the patch is applied to a portion of the base disk image corresponding to the unmodified portion of the base disk image. The delta file is applied to the patched copy of the base disk image.

Claims

1. A method for updating a plurality of user disk images, each of the plurality of user disk images derived from a common base disk image and a delta image comprising a plurality of delta files, each of the delta files representing at least one difference between one of the plurality of user disk images and the base disk image, the method comprising:

applying a delta file to a base disk image to generate a second disk image comprising a portion of the base disk image modified by the delta file and an unmodified portion of the base disk image;

applying a patch to a copy of the base disk image;

in response to determining that the patch is applied to at least one file of the copy of the base disk image corresponding to the unmodified portion of the base disk image, applying the delta file to the patched copy of the base disk image; and

in response to determining that the patch is applied to a portion of the base disk image corresponding to the portion of the base disk image modified by the delta file, determining not to apply at least one delta file to the modified portion of the base disk image.

2. The method of claim 1 further comprising mounting the base disk image, the second disk image, and the patched copy of the base disk image in a computing environment.

3. The method of claim 1 further comprising mounting the base disk image, the second disk image, and the patched copy of the base disk image in a virtual machine environment.

4. The method of claim 1 further comprising copying the delta file into a second delta disk image associated with the patched copy of the base disk image, responsive to the determination.

5. The method of claim 1, wherein applying the delta file to the base disk image further comprises applying the delta file of a delta disk image to the base disk image to generate the second disk image, the delta disk image comprising at least one of a plurality of delta files representing at least one difference between a user disk image and the base disk image.

6. The method of claim 1, wherein determining further comprises determining, via a merge process, that the patch is applied to a portion of the base disk image corresponding to the unmodified portion of the base disk image.

7. The method of claim 1, wherein applying further comprises applying, via a merge process, the delta file to the patched copy of the base disk image.

8. The method of claim 1 further comprising:

applying the delta file to at least one file of the patched copy of the base disk image.

9. The method of claim 1 further comprising:

determining that the patch is applied to a registry portion of the base disk image corresponding to the modified portion of the base disk image; and

merging the delta file, at a registry key level, to a portion of the patched copy of the base disk image corresponding to the modified portion of the base disk image.

10. The method of claim 1 further comprising:

determining that the patch is applied to one of;

a database and a log-file portion of the base disk image corresponding to the modified portion of the base disk image; and

merging the delta file, using at least one of;

timestamps and heuristics, to a portion of the patched copy of the base disk image corresponding to the modified portion of the base disk image.

11. The method of claim 1 further comprising generating a second delta disk image storing at least one delta file that when applied to the patched copy of the base disk image generates a third disk image.

12. The method of claim 1, wherein applying the delta file to the patched copy of the base disk image further comprises determining, by a rule engine, to apply the delta file to the patched copy of the base disk image.

13. The method of claim 1 further comprising:

applying a patch to a copy of the second disk image;

determining that the patch is applied to a portion of the copy of the second disk image corresponding to a portion of the base disk image modified by a delta file;

determining that the patch in the patched copy of the base disk image is applied to a portion of the base disk image unmodified by the delta file; and

applying the delta file to the patched copy of the base disk image.

14. A computer implemented system implemented in hardware in combination with software to update a plurality of user disk images, each of the plurality of delta disks derived from a common base disk image and a delta image comprising a plurality of delta files, each of the delta files representing at least one difference between one of the plurality of user disk images and the base disk image, comprising:

a base disk image;

a delta disk image comprising a plurality of delta files, wherein;

at least one of the plurality of delta files is applied to the base disk image to generate a second disk image comprising a portion of the base disk image modified by the delta file and an unmodified portion of the base disk image;

a patch configured for application to a copy of the base disk image to generate a patched copy of the base disk image; and

a computing environment configured to;

in response to a determination that the patch is applied to a portion of the base disk image corresponding to the unmodified portion of the base disk image, apply the delta file to the patched copy of the base disk image; and

in response to a determination that the patch is applied to a portion of the base disk image corresponding to the portion of the base disk image modified by the delta file, determine not to apply at least one delta file to the modified portion of the base disk image.

15. The system of claim 14, wherein the computing environment is further configured to merge the base disk image, the second disk image, and the patched copy of the base disk image.

16. The system of claim 14, wherein the computing environment is a virtual machine environment.

17. The system of claim 14, wherein the computing environment is further configured to manipulate files between disk image format and delta file format.

18. The system of claim 14, wherein the computing environment further comprises an operating system and at least one tool for manipulating disk images.

19. The system of claim 14 wherein the delta file is applied to the patched copy of the base disk image.

20. The system of claim 14, wherein the computing environment is configured to apply via a merge process, the delta file to the patched copy of the base disk image.

21. The system of claim 14, wherein the patch is applied to at least one file of the base disk image corresponding to the unmodified portion of the base disk image.

22. The system of claim 14, wherein the delta file is applied to at least one file of the patched copy of the base disk image.

23. The system of claim 14, wherein the computing environment further comprises a tool for reading and writing disk images.