This document compares multiple software update tools in order to implement the CIP software updates architecture. We compared them from different points of view such as:

1. network and storage efficiency
2. ability to integrate with Debian-based build tools (Deby, ISAR, Debos)
3. community and member's expertise
4. support local and network updates
5. security support (encryption, digital certificates, integrity)
6. extendable with scripts

* Hawkbit

• supported by SWUpdate and RAUC
• Written in Java
• Docker compose available
  • https://github.com/eclipse/hawkbit/tree/master/hawkbit-runtime/docker

* Mender.IO server

• written in Go
• requires some effort to support it from SWUpdate
• microservices architecture and docker-compose
  • https://github.com/BaseflowIT/mender-server/blob/master/docker-compose.demo.yml

* HERE OTA community

• microservices architecture and Kubernetes
  • https://github.com/advancedtelematic/ota-community-edition/blob/master/config/images.yaml

* Custom Http server

• Supported by SWUpdate
  • https://sbabic.github.io/swupdate/suricatta.html#support-for-general-purpose-http-server

* SWupdate + librsync

• https://sbabic.github.io/swupdate/swupdate.html
• Bad points
  • hard to manage updates from v1 to v5 directly
  • depends on libubootenv which needs to be rebuilt for each target.
• Good points
  • modular: you can enable/disable each function
  • good community: Stephano, Denx(u-boot)
  • CIP members experience (Siemens)
  • supports yocto (meta-swupdate) and debian (on-going)
  • low bandwidth (librsync deltas)
  • u-boot interface
  • can work with block and file-system trees

* meta-updater

• https://github.com/advancedtelematic/meta-updater
• Bad points
  • hard to use in a non-yocto build system
  • hard to manage updates from v1 to v5 directly
  • does not support efibootguard
  • has intrusive dependencies (meta-python)
  • does not support A/B partitions updating
• Good points
  • uses deltas through OSTree (low bandwidth)
  • integrated with yocto
  • rollback capacity
  • atomic updates
  • uses 1 partition and 1 ramdisk (low storage required)
  • supports u-boot

* RAUC + Casync (command)

• https://github.com/rauc/rauc
• https://rauc.readthedocs.io/en/latest/
• Bad points
  • Casync has many dependencies and requires new library versions
  • Casync needs to calculate chunks on the target device
  • The target device needs extra storage for the chunks store
• Good points
  • Casync can update from version 1 to version N
  • Casync divides images in chunks (delta-like updates)
  • Casync supports file trees with fs metadata and block images
  • Casync has good storage properties thanks to reuse of chunks

We compared several methods and read other comparison reports (see “Comparison references” below). All methods have their own advantages and disadvantages. For the next phase, we decided to go for the “SWupdate + librsync” method because it satisfies the requirements specified by the CIP Software Updates Architecture and Siemens has important experience using that method. We also decided to use Hawkbit on the server side for our initial prototype. Having said that, the project will be open to other update methods and tools and we welcome any contribution in that sense.

Finally, here is a document that contains a table where CIP members compared several software update methods:

• https://docs.google.com/presentation/d/1NIjspcmjo2w6FxK64WdysfFG4jayxL0q0lU_PP569k8 (software updates survey)

* https://elinux.org/Secure_OTA_Update * https://wiki.yoctoproject.org/wiki/System_Update * https://mkrak.org/wp-content/uploads/2018/04/FOSS-NORTH_2018_Software_Updates.pdf * https://events.linuxfoundation.org/wp-content/uploads/2017/12/Strategies-for-Developing-and-Deploying-your-Embedded-Applications-and-Images-Mirza-Krak-Mender.io_.pdf * http://events17.linuxfoundation.org/sites/events/files/slides/ELC2017_SWUpdate.pdf * https://events.static.linuxfound.org/sites/events/files/slides/linuxcon-japan-2016-softwre-updates-sangorrin.pdf * https://events.linuxfoundation.org/wp-content/uploads/2017/12/ELCE-2018-Update-Tools-BoF_Jan-Lubbe.pdf * https://elinux.org/images/f/f5/Embedded_Systems_Software_Update_for_IoT.pdf * https://elinux.org/images/3/31/Comparison_of_Linux_Software_Update_Technologies.pdf