Boot and update from runtime merged image fragments
A feature is updated on a computing device. One or more composite image files are accessed that correspond to updates to be implemented in the computing device. The composite image files are signed containers. A runtime in-memory merge of the composite image files is performed. The merged composite image files are exposed as a read-only volume. The features are made available to the computing device. A system boot using the read-only volume can be initiated.
1. A computer-implemented method for updating an operating system of a computing device, the method comprising:
determining an update that is to be implemented in the operating system;
accessing a plurality of composite image files that correspond to the update, each of the composite image files comprising an image fragment of a set of image fragments that collectively form a complete operating system image, wherein the composite image files are included in a signed container containing files for implementing the update to the operating system;
merging the image fragments on the computing device; and
initiating a system boot of the computing device using the merged image fragments.
2. The computer-implemented method of claim 1 , wherein the merging comprises performing an in-memory merge.
3. The computer-implemented method of claim 1 , wherein a layout of the composite image files comprises a root file, a metadata region, and one or more data regions.
4. The computer-implemented method of claim 3 , wherein the one or more data regions include a small data region and a data region.
5. The computer-implemented method of claim 4 , wherein the small data region is for file content that is less than a predetermined size, and the data region is for file content that meets or exceeds the predetermined size.
6. The computer-implemented method of claim 5 , wherein the data region is aligned with a start of each region to a page size.
7. The computer-implemented method of claim 1 , wherein the signed container includes data to track what directory or key is associated with security for the signed container.
8. The computer-implemented method of claim 1 , wherein the composite image files are processed as individual packages prior to delivery to the computing device.
9. The computer-implemented method of claim 1 , further comprising storing modifications to the operating system defined by the composite image files as a read-write layer.
10. The computer-implemented method of claim 1 , further comprising exposing the merged image fragments as a read-only volume, wherein the system boot is initiated using the read-only volume.
11. A system comprising:
one or more processors;
a memory in communication with the one or more processors, the memory having computer-readable instructions stored thereupon which, when executed by the one or more processors, cause the system to perform operations comprising:
determining an operating system update that is to be implemented in a computing device;
accessing a plurality of files and data associated with the operating system update;
generating a plurality of image fragments for implementing the operating system update, the image fragments collectively forming a complete operating system image, wherein the image fragments are combinable at the computing device by merging the image fragments; and
sending the plurality of image fragments to the computing device.
12. The system of claim 11 , wherein a layout of the plurality of image fragments comprises a root file, a metadata region, and one or more data regions.
13. The system of claim 12 , wherein:
the one or more data regions include a small data region and a data region;
the small data region is for file content that is less than a predetermined size;
the data region is for file content that meets or exceeds the predetermined size; and
the data region is aligned with a start of each region to a page size.
14. The system of claim 11 , wherein the merging comprises a runtime in-memory merge of the image fragments.
15. The system of claim 11 , wherein the image fragments are included in a signed container.
16. A computer-readable medium having encoded thereon computer-executable instructions that, when executed, cause one or more processing units of a computing device to execute operations comprising:
accessing a plurality of image fragments that correspond to an update that is to be implemented in the computing device, the image fragments collectively forming a complete operating system image;
merging the image fragments; and
initiating a system boot using the merged image fragments.
17. The computer-readable medium of claim 16 , wherein the merging comprises performing a runtime in-memory merge of the image fragments.
18. The computer-readable medium of claim 16 , wherein the plurality of image fragments are included in a signed container.
19. The computer-readable medium of claim 16 , wherein the merged image fragments are exposed as a read-only volume, and the system boot is initiated using the read-only volume.
20. The computer-readable medium of claim 16 , wherein the image fragments are processed as individual packages prior to delivery to the computing device.