Boot and update from runtime merged image fragments

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 one or more operating system updates that are to be implemented in a computing device;
• accessing a plurality of files and data associated with the updates;
• generating a plurality of composite image files for implementing the update, each of the composite image files comprising an image fragment of a set of image fragments that form a complete operating system image, wherein the composite image files are signed containers that are combinable at the computing device by performing a runtime in-memory merge of the composite image files;
• and
• sending the signed containers to the computing device.

A computer-readable medium having encoded thereon computer-executable instructions that, when executed by one or more processing units of a computing device, cause the computing device to perform operations comprising:

• accessing a plurality of composite image files that correspond to an update that is to be implemented in the computing device, each of the composite image files comprising an image fragment of a set of image fragments that form a complete operating system image, wherein the one or more composite image files are signed containers;
• performing a runtime in-memory merge of the composite image files;
• exposing the merged composite image files as a read-only volume;
• and
• initiating a system boot using the read-only volume.