DevOps For Embedded Software Development
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DevOps For Embedded Software Development

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A brief overview of DevOps practices and tools. Presented at the DevOps Boulder Meetup, May 20th, 2013.

A brief overview of DevOps practices and tools. Presented at the DevOps Boulder Meetup, May 20th, 2013.

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DevOps For Embedded Software Development DevOps For Embedded Software Development Presentation Transcript

  • DEVOPS FOR EMBEDDEDSOFTWARE DEVELOPMENTScott HallockMay 20, 2013
  • Agenda• Introduction• What We Do• How We Do It• Strengths and Challenges
  • Introduction BAIT• Build, Automation, Integration, and Test• Continuous integration and automated release for Linux software products • 3-5 Linux-based operating systems • Software releases nearly every day • Build Linux from source thousands of times per day • Support a worldwide Linux developer community of more than 1,000 • More than 50 actively developed codelines • Integrate more than 200 code changes per day
  • Objectives• High-level overview of embedded DevOps processes and practices• Start an exchange of knowledge between embedded and non-embedded DevOps communities• Interactivity • Please interrupt to ask questions • Detailed, tangential discussions are welcome
  • Embedded Development Is Different• Tools don’t evolve quickly • Command line compilers • Everybody loves the preprocessor • printf debugging • Eclipse viewed with suspicion• Product focus • Customers get the code, not just the experience • Fix it, ship it, forget it • Standard release: zip archive • Many similar codelines under active development simultaneously
  • Continuous Integration Review Build Deploy Test Integrate
  • Continuous Integration Deployment• Datacenter-quality hardware• Rack-mountable form factor• Stable, controlled operating system and management software• Well-defined power and thermal characteristics
  • Embedded Continuous Integration Review Build Load Test Integrate
  • Target Load Challenges• Developer-quality hardware• Irregular form factor• Unstable loading software, boot code, operating system• Unknown power and thermal characteristics• Slow and unstable JTAG, USB loading interfaces
  • Target Load Solutions• Single controlling server for each target hardware board• Physical access to production hardware • Easily reconfigure physical racks to accommodate novel form factors • Repair or replace unstable, malfunctioning target hardware• Fault-tolerant software • Lots of retries! • Heuristics to infer target state based on observable outputs• Change the target hardware design
  • Time Constraints 90 minutes Review Build Load Test Integrate 15 minutes
  • Preverification 90 minutes, many changes Review Build Load Test Integrate Build 60 minutes, one change
  • Automated Release Build Test Approve git push
  • Code Change Control: git• http://git-scm.com• Distributed is great! • Developers can work offline, at customer sites with no network access. • Collaboration is easier. Everyone has complete history.
  • git Problems• Everyone gets everything • Do you check in a helper binary every time you change it? • Did you accidentally commit some trade secrets and then revert them later? • Did your developers include an estimate of your customers’ intelligence in their commit message? • You create integration tags fifty times per day. • Your continuous integration system creates “temporary” integration branches twenty-five times per day.
  • git Problems• git trees become unusable over time. Are you garbage collecting? • On your central repositories? • When you mirror your central repositories? • On your external release servers? • On your Continuous Integration build machines?
  • git Problems• Cherry-picking • I can just have the two changes I want for today’s release? Great! • Breaks all traceability, barring commit message kludges
  • Codeline Definition: repo• http://source.android.com/source/using-repo.html• Allows for many git projects to be combined into a single source tree and operated upon as a single entity.• Developers use it to download and sync code, most use git commands for everything else.<project name=“kernel/msm” path=“kernel”revision=“refs/heads/msm-3.4” /><project name=“kernel/lk”path=“bootable/bootloader/lk”revision=“refs/heads/master” />
  • repo: Project Addition Build Test Approve git push!!!
  • repo: Branch Change<project name=“kernel/msm” path=“kernel”revision=“refs/heads/msm-3.4” /><project name=“kernel/lk”path=“bootable/bootloader/lk”revision=“refs/heads/master” /><project name=“kernel/msm” path=“kernel”revision=“refs/heads/msm-3.4” /><project name=“kernel/lk”path=“bootable/bootloader/lk”revision=“refs/heads/stable” />
  • repo: Branch Change Build Test Approve git push!!!
  • repo: Branch Change• Merge? • “master” branch contains dozens of bugs. You just merged them with your stable branch.• Force push? • Now your customer doesn’t understand what happened to all the changes they painstakingly integrated for the last month.• Create new branch on release server? • Customer still has to re-integrate their changes. • At least the old branch is available for reference.• Stop doing that! • How am I supposed to make my release?
  • repo: Shared Branchescustomer-1.xml:<project name=“kernel/msm” path=“kernel”revision=“refs/heads/msm-3.4” /><project name=“kernel/lk”path=“bootable/bootloader/lk”revision=“refs/heads/customer-1” />customer-2.xml<project name=“kernel/msm” path=“kernel”revision=“refs/heads/msm-3.4” /><project name=“kernel/lk”path=“bootable/bootloader/lk”revision=“refs/heads/customer-2” />
  • Gerrit: Code Review and More• https://code.google.com/p/gerrit/• Code review, access control, source code mirroring
  • Gerrit: Code Review• States Tracked: • Code Review (-2 - +2): Peer opinion of design and code quality • Verified (-1 - +1): Code works at runtime• Roles • Author/Committer • Approver • Integrator
  • Gerrit: Access Control• Most actions in Gerrit are access controlled • Code visibility • Upload • Review • Merge• Access control can be based on users, on local groups, or on LDAP groups.• Access control is complex. Automation is recommended.
  • Gerrit: Mirroring Master Slave Slave Slave• Single master• Slaves can’t mirror to other slaves• Smart git push based mirroring • Better than any mirroring scheme not based on application layer knowledge of git• Errors not handled gracefully • Obvious errors are re-queued for later retries
  • Code Aurora Forum• http://codeaurora.org
  • Other Tools• Electric Commander • http://www.electriccloud.com/products/electriccommander.php• Jira • https://www.atlassian.com/software/jira/overview• BlackDuck • http://www.blackducksoftware.com/products/black-duck-suite• Gitolite • http://gitolite.com/gitolite/
  • Strengths• Chasing the sun • Operational teams in major timezones • Handoff procedure is well understood• Cheap scaling • Use simple, dumb tools and relentlessly parallelize • Understand where human intervention is inevitable• Sync, build efficiency • Custom software atop repo for very efficient repo syncs • Fastest clean builds in the business• Automated release • Very complex branching structure is released automatically multiple times per day
  • Challenge: Source Code Distribution Master Slave Slave!!! Slave• Single master mirroring has scaling limits • Git push is CPU intensive• Gerrit doesn’t report well when a slave is out of sync • Custom software needed• An independent and easily monitored sync solution is desired
  • Challenge: Build Distribution Build Test Approve git push 25GB x Boulder, ~50/day San Diego, Santa Clara, India, China, Korea…
  • Challenge: Two-Way Integration Internal Codeline Integrated Codeline Partner Codeline