# Host update mechanism

// SPDX-FileCopyrightText: 2022 Unikie
// SPDX-License-Identifier: GFDL-1.3-no-invariants-or-later OR CC-BY-SA-4.0

## Status
Proposed

## Context
Spectrum OS has no implementation for software update. The host - consisting of
Linux kernel, KVM, cloud-hypervisor and minimal user space tools - software
updates are required to support feature development and security fixes.

## Decision
A-B partitioning created by Spectrum installer Installer sets up the system on
partition A of the block device A-B update scheme where user (or installer)
writes the update image to partition B Bootloader provides four boot options:
A, A mutable, B, B mutable

## Consequences
Default boot selection, incremental updates (e.g. overlays), network update
postponed for later.
