Direct Migration of Software Images with Streaming Technique

• US 20130219161A1
• Filed: 11/03/2011
• Published: 08/22/2013
• Est. Priority Date: 11/23/2010
• Status: Active Grant

• Current Assignee: ServiceNow Incorporated
• Original Assignee: International Business Machines Corporation
• Inventors: Fontignie, Jacques, Marinelli, Claudio, Scotton, Paolo, Vuilleumier Stueckelberg, Marc
• Granted Patent: US 9,086,892 B2
• Time in Patent Office: Days
• US Class Current: 713/2
• CPC Class Codes: G06F 8/63 Image based installation; Cloning; Build to order
• CPC Class Codes: G06F 9/4401 Bootstrapping security arrangements therefor G06F21/57

Abstract

A mechanism is provided for migrating a software image installed on a source data-processing entity to a target data-processing entity. The target data-processing entity is booted from a preliminary bootstrap program. The software image is mounted as a remote mass memory on the target data-processing entity. A primary bootstrap program of the software image is copied onto a local mass memory of the target data-processing entity. The target data-processing entity is re-booted from the primary bootstrap program thereby loading a streaming function, and serving each request of accessing a memory block on the target data-processing entity by the streaming function. In response to the memory block missing from the local mass storage, the streaming function downloads the memory block from the software image and stores the memory block into the local mass memory. Otherwise, the streaming function retrieves the memory block from the local mass memory otherwise.

Claims

1. A migration method for migrating a software image installed on a source data-processing entity to a target data-processing entity, the migration method comprising:

booting the target data-processing entity from a preliminary bootstrap program providing a standalone preliminary operative system,

mounting the software image as a remote mass memory on the target data-processing entity,

copying a primary bootstrap program of the software image onto a local mass memory of the target data-processing entity, the primary bootstrap program comprising a streaming function adapted to migrate the software image to the target data-processing entity,

re-booting the target data-processing entity from the primary bootstrap program on the local mass memory of the target data-processing entity thereby loading the streaming function, and

serving each request of accessing a memory block on the target data-processing entity by the streaming function, the streaming function downloading the memory block from the software image installed on the source data-processing, entity and storing the memory block into the local mass memory of the target data-processing entity in response to a lacking of the memory block in the local mass memory of the target data-processing entity, or retrieving the memory block from the local mass memory of the target data-processing entity otherwise.

2. The migration method according to claim 1, wherein for each request of accessing the memory block in an update mode the method further comprising:

updating the memory block in the local mass memory of the target data-processing entity.

3. The migration method according to claim 1, further comprising:

disabling the streaming function for retrieving each memory block directly from the local mass memory of the target data-processing entity in response to the storing of a number of memory blocks corresponding to a size of the software usage in the local mass memory of the target data-processing entity.

4. The migration method according to claim 1, further comprising:

monitoring a workload of the target data-processing entity or the source data-processing entity, and

downloading a set of selected memory blocks being not stored in the local mass memory of the target date-processing entity from the software image installed on the source data-processing entity and storing the selected memory blocks into the local mass memory of the target data-processing entity in response to the workload failing below a threshold value.

5. The migration method according to claim 1, wherein the target data-processing entity is a target physical computer, and wherein booting the target data-processing entity from the preliminary bootstrap program comprises:

booting the target physical computer from a network bootstrap program.

6. The migration method according to claim 1, wherein the target data-processing entity is a target virtual machine running on a target hypervisor, and wherein booting the target data-processing entity from a preliminary bootstrap program comprises:

booting the target virtual machine from a booting virtual disk external to the target virtual machine.

7. The migration method according to claim 6, wherein booting the target virtual machine from the booting virtual disk comprises:

downloading the booting virtual disk by the target hypervisor.

8. The migration method according to claim 6, wherein booting the target virtual machine from the booting virtual disk comprises:

changing a boot sector of the target virtual machine to point to the booting virtual disk.

9. The migration method according claim 1, wherein the source data-processing entity is a source physical computer, and wherein the migration method further comprises:

booting the source physical computer from a further preliminary bootstrap program providing a further standalone preliminary operative system without mounting the software image installed on the source data-processing entity, and

preparing the software image installed on the source data-processing entity in a consistent state for remote access thereof by the target data-processing entity.

10. The migration method according to claim 9, wherein booting the source physical computer from the further preliminary bootstrap program comprises:

booting the source physical computer from a further network bootstrap program.

11. The migration method according to claim 1, wherein the source data-processing entity is a source virtual machine miming on a source hypervisor, and wherein the migration method further comprises:

preparing the software image installed on the source data-processing entity in a consistent state for remote access thereof by the target data-processing entity, the software image installed on the source data-processing entity being prepared with the source virtual machine in a turned off state.

12. A computer program product comprising a computer readable medium having a computer readable program for causing a data-processing system to migrate a software image installed on a source data-processing entity to a target data-processing entity stored therein, wherein the computer readable program, when executed on the data-processing system, causes the data processing system to:

boot the target data-processing entity from a preliminary bootstrap program providing a standalone preliminary operative system,

mount the software image as a remote mass memory on the target data-processing entity,

copy a primary bootstrap program of the software image onto a local mass memory of the target data-processing entity, the primary bootstrap program comprising a streaming function adapted to migrate the software image to the target data-processing entity,

re-boot the target, data-processing entity from the primary bootstrap program on the local mass memory of the target data-processing entity thereby loading the streaming function, and

serve each request of accessing a memory block on the target data-processing entity by the streaming function, the streaming function downloading the memory block from the software image installed on the source data-processing entity and storing the memory block into the local mass memory of the target data-processing entity in response to a lacking of the memory block in the local mass memory of the target data-processing entity, or retrieving the memory block from the local mass memory of the target data-processing entity otherwise.

13. A system for migrating a software image installed on a source data-processing entity to a target data-processing entity comprising:

a processor; and

a memory coupled to the processor, wherein the memory comprises instructions which, when executed by the processor, cause the processor to;

boot the target data-processing entity from a preliminary bootstrap program providing a standalone preliminary operative system,

mount the software image as a remote mass memory on the target data-processing entity,

copy a primary bootstrap program of the software image onto a local mass memory of the target data-processing entity, the primary bootstrap program comprising a streaming function adapted to migrate the software image to the target data-processing entity,

re-boot the target data-processing entity from the primary bootstrap program on the local mass memory of the target data-processing entity thereby loading the streaming function, and

serve each request of accessing a memory block on the target data-processing entity by the streaming function, the streaming function downloading the memory block from the software image installed on the source data-processing entity and storing the memory block into the local mass memory of the target data-processing entity in response to a lacking of the memory block in the local mass memory of the target data-processing entity, or retrieving the memory block from the local mass memory of the target data-processing entity otherwise.

14. The system according to claim 13, wherein for each request of accessing the memory block in an update mode the instructions further cause the processor to:

update the memory block in the local mass memory of the target data-processing entity.

15. The system according to claim 13, wherein the instructions further cause the processor to:

disable the streaming function for retrieving each memory block directly from the local mass memory of the target data-processing entity in response to the storing of a number of memory blocks corresponding to a size of the software image in the local, mass memory of the target data-processing entity.

16. The system according to claim 13, wherein the instructions further cause the processor to:

monitor a workload of the target data-processing entity or the source data-processing entity, and

download a set of selected memory blocks being not stored in the local mass memory of the target data-processing entity from the software image installed on the source data-processing entity and storing the selected memory blocks into the local mass memory of the target data-processing entity in response to the workload falling below a threshold value.

17. The system according to claim 13, wherein the target data-processing entity is a target physical computer, and wherein the instructions to boot the target data-processing entity from the preliminary bootstrap program further cause the processor to comprises:

boot the target physical computer from a network bootstrap program.

18. The system according to claim 13, wherein the target data-processing entity is a target virtual machine running on a target hypervisor, and wherein the instructions to boot the target data-processing entity from a preliminary bootstrap program further causes the processor to:

boot the target virtual machine from a booting virtual disk external to the target virtual machine.

19. The system according to claim 18, wherein the instructions to boot, the target virtual machine from the booting virtual disk further causes the processor to;

download the booting virtual disk by the target hypervisor.

20. The system according to claim 18, wherein the instructions to boot the target virtual machine from the booting virtual disk further causes the processor to;

change a boot sector of the target virtual machine to point to the booting virtual disk.