00
This commit is contained in:
262
docs/00-series-overview.md
Normal file
262
docs/00-series-overview.md
Normal file
@@ -0,0 +1,262 @@
|
||||
# OTA Reference Design
|
||||
|
||||
> A practical guide to designing reliable, secure, and maintainable over-the-air (OTA) update systems for embedded Linux devices.
|
||||
|
||||
---
|
||||
|
||||
## About This Repository
|
||||
|
||||
This repository presents a practical reference design for building over-the-air (OTA) update systems for embedded Linux devices.
|
||||
|
||||
Rather than documenting a particular framework or vendor-specific solution, it focuses on the engineering principles that make OTA systems reliable, secure, and maintainable.
|
||||
|
||||
The goal is to explain **why** modern OTA systems are designed the way they are, what problems they solve, and what trade-offs different approaches involve.
|
||||
|
||||
Although many examples use Raspberry Pi as a demonstration platform, the concepts are applicable to a wide range of embedded Linux systems.
|
||||
|
||||
---
|
||||
|
||||
## Why This Repository Exists
|
||||
|
||||
There is no shortage of documentation for OTA frameworks.
|
||||
|
||||
You can easily find documentation for tools such as:
|
||||
|
||||
- Mender
|
||||
- RAUC
|
||||
- SWUpdate
|
||||
- OSTree
|
||||
- A/B Updates
|
||||
|
||||
However, these resources usually explain **how to use a particular tool**, not **why OTA systems are designed this way**.
|
||||
|
||||
Questions like these are often left unanswered:
|
||||
|
||||
- Why do many devices use A/B partitions?
|
||||
- Why are bootloaders involved in the update process?
|
||||
- Why is rollback necessary?
|
||||
- What happens if power is lost during an update?
|
||||
- Why are update images signed?
|
||||
- Why are atomic updates important?
|
||||
- How do production devices remain recoverable after failures?
|
||||
|
||||
This repository attempts to answer those engineering questions.
|
||||
|
||||
---
|
||||
|
||||
## What You'll Learn
|
||||
|
||||
Throughout this series we will explore topics including:
|
||||
|
||||
- OTA architecture
|
||||
- Boot process
|
||||
- Update strategies
|
||||
- Full-image vs package updates
|
||||
- A/B partition layouts
|
||||
- Bootloader interaction
|
||||
- Rollback mechanisms
|
||||
- Atomic updates
|
||||
- Image verification
|
||||
- Digital signatures
|
||||
- Secure Boot
|
||||
- Failure recovery
|
||||
- Delta updates
|
||||
- Version management
|
||||
- Testing strategies
|
||||
- Production deployment considerations
|
||||
|
||||
The emphasis is always on understanding the underlying design rather than memorizing a particular implementation.
|
||||
|
||||
---
|
||||
|
||||
## Repository Structure
|
||||
|
||||
```text
|
||||
ota-reference-design/
|
||||
│
|
||||
├── docs/
|
||||
│ ├── 00-series-overview.md
|
||||
│ ├── 01-ota-introduction.md
|
||||
│ ├── 02-update-strategies.md
|
||||
│ ├── ...
|
||||
│
|
||||
├── diagrams/
|
||||
│ └── plantuml/
|
||||
│
|
||||
├── examples/
|
||||
│ ├── raspberry-pi/
|
||||
│ ├── qemu/
|
||||
│ └── simulations/
|
||||
│
|
||||
├── adr/
|
||||
│ ├── ADR-001-repository-name.md
|
||||
│ ├── ADR-002-license.md
|
||||
│ └── ADR-003-reference-design.md
|
||||
│
|
||||
└── README.md
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## Learning Path
|
||||
|
||||
The chapters are designed to build on each other.
|
||||
|
||||
```text
|
||||
Introduction
|
||||
│
|
||||
▼
|
||||
Update Strategies
|
||||
│
|
||||
▼
|
||||
System Architecture
|
||||
│
|
||||
▼
|
||||
Boot Process
|
||||
│
|
||||
▼
|
||||
Storage Layout
|
||||
│
|
||||
▼
|
||||
Atomic Updates
|
||||
│
|
||||
▼
|
||||
Rollback
|
||||
│
|
||||
▼
|
||||
Security
|
||||
│
|
||||
▼
|
||||
Testing
|
||||
│
|
||||
▼
|
||||
Production Deployment
|
||||
```
|
||||
|
||||
While each chapter can be read independently, following the series in order provides a much deeper understanding of the complete system.
|
||||
|
||||
---
|
||||
|
||||
## Engineering Philosophy
|
||||
|
||||
This repository is intentionally different from product documentation.
|
||||
|
||||
Instead of presenting a single "correct" solution, every topic discusses:
|
||||
|
||||
- why a particular design exists;
|
||||
- which problem it solves;
|
||||
- what alternatives are available;
|
||||
- what trade-offs each approach introduces;
|
||||
- when another solution may be more appropriate.
|
||||
|
||||
Real-world engineering is rarely about choosing the only correct answer.
|
||||
|
||||
It is about understanding constraints and making informed decisions.
|
||||
|
||||
---
|
||||
|
||||
## The Reference Design
|
||||
|
||||
The architecture presented throughout this repository is a coherent reference design.
|
||||
|
||||
Real products may use different technologies or frameworks while following the same architectural principles.
|
||||
|
||||
For example, one project may use RAUC, another SWUpdate, and another a completely custom implementation.
|
||||
|
||||
The implementation details may differ.
|
||||
|
||||
The underlying engineering principles usually do not.
|
||||
|
||||
---
|
||||
|
||||
## Practical Examples
|
||||
|
||||
Where possible, theoretical discussions are accompanied by practical material, including:
|
||||
|
||||
- architecture diagrams
|
||||
- boot sequence walkthroughs
|
||||
- storage layout examples
|
||||
- failure scenarios
|
||||
- Raspberry Pi demonstrations
|
||||
- QEMU-based experiments
|
||||
- implementation notes
|
||||
|
||||
The objective is to connect high-level architecture with practical implementation.
|
||||
|
||||
---
|
||||
|
||||
## Intended Audience
|
||||
|
||||
This repository is intended for:
|
||||
|
||||
- Embedded Linux developers
|
||||
- Firmware engineers
|
||||
- Embedded software engineers
|
||||
- System architects
|
||||
- Students learning embedded systems
|
||||
- Engineers preparing for technical interviews
|
||||
- Anyone interested in understanding OTA system design
|
||||
|
||||
No prior experience with OTA frameworks is assumed.
|
||||
|
||||
---
|
||||
|
||||
## How to Read This Repository
|
||||
|
||||
If you are new to OTA systems, simply start with Chapter 1 and continue in order.
|
||||
|
||||
If you already have embedded Linux experience, feel free to jump directly to topics that interest you.
|
||||
|
||||
If you are looking for implementation details, the accompanying examples provide practical demonstrations of the concepts discussed in the documentation.
|
||||
|
||||
---
|
||||
|
||||
## OTA at a Glance
|
||||
|
||||
The following diagram illustrates the overall update lifecycle that will be explored throughout this repository.
|
||||
|
||||
```text
|
||||
OTA Server
|
||||
│
|
||||
Signed Update
|
||||
│
|
||||
┌───────────▼───────────┐
|
||||
│ Download Manager │
|
||||
└───────────┬───────────┘
|
||||
│
|
||||
Verify Signature
|
||||
│
|
||||
Verify Integrity
|
||||
│
|
||||
Install Update
|
||||
│
|
||||
Mark Boot Target
|
||||
│
|
||||
Reboot Device
|
||||
│
|
||||
Bootloader Decision
|
||||
┌─────────┴─────────┐
|
||||
│ │
|
||||
Boot Success Boot Failure
|
||||
│ │
|
||||
▼ ▼
|
||||
Commit Update Rollback
|
||||
```
|
||||
|
||||
Each stage of this process will be examined in detail in the chapters that follow.
|
||||
|
||||
---
|
||||
|
||||
## Contributing
|
||||
|
||||
Contributions, suggestions, and discussions are welcome.
|
||||
|
||||
If you have ideas for improvements, additional examples, or alternative approaches, feel free to open an issue or submit a pull request.
|
||||
|
||||
---
|
||||
|
||||
## License
|
||||
|
||||
This repository is released under the MIT License.
|
||||
|
||||
See the LICENSE file for details.
|
||||
Reference in New Issue
Block a user