GopherCon Denver LT 2018
- 2. Docker daemon eth0 Linux machine Docker Daemon
- 3. Docker runtime adopted Go • Promoted wider adoption of Go as a systems language • Bug fixes in Docker produced more Go programmers • Identifying systems level problem in Go runtime related to syscalls / threads
- 4. Isolation in Docker container: namespaces • Process trees (PID Namespace) • Mounts (MNT namespace) • Network (Net namespace) • Users / UIDs (User Namespace) • Hostnames (UTS Namespace) • Inter Process Communication (IPC Namespace)
- 5. Lets see this in action
- 6. Running a Go Process on Linux machine eth0 Linux machine Go Process OS thread Goroutine
- 7. Add new Network Namespace with lo (loopback) only interface eth0 net namespaces n Linux machine Go Process OS thread Goroutine
- 8. Adding worker goroutines to new network namespaces eth0 Worker goroutines net namespaces n Linux machine Go Process OS thread Goroutine runtime.LockOSThread()
- 9. Adding worker goroutines to host network namespace eth0 Worker goroutines net namespaces n Linux machine Go Process OS thread Goroutine runtime.LockOSThread()
- 10. Adding worker goroutines to host network namespace eth0 more Worker goroutines net namespaces n Linux machine Go Process OS thread Goroutine runtime.LockOSThread()
- 11. Incorrect interfaces detected by goroutines eth0 more Worker goroutines net namespaces n Linux machine Go Process goroutine with wrong interface info
- 12. Go runtime scheduler M P G G G G M P G M P G OS thread Processor (Logical) Goroutine
- 13. Go runtime scheduler M P G G G G M P G G G Global queue M P G OS thread Processor (Logical) Goroutine
- 14. Go runtime Scheduler M P G G G G M P G G G M P G G G M P G G G G G G Global queue M P G OS thread Processor (Logical) Goroutine
- 15. Go runtime Scheduler M P G G G G M P G G G M P G G G M P G G G G G G Global queue New threads inherit state from already running threads
- 16. Go runtime model eth0 more Worker goroutines net namespaces n Linux machine Go Process OS thread Goroutine runtime.LockOSThread()
- 17. Go runtime model eth0 more Worker goroutines net namespaces n Linux machine Go Process
- 18. How Go 1.10 Fixed it
- 19. Go runtime scheduler M P G G G G M P G M P G OS thread Processor (Logical) Goroutine
- 20. Go runtime scheduler M P G M P G M P G OS thread Processor (Logical) Goroutine runtime.LockOSThread()
- 21. Go runtime scheduler in go 1.10 M P G M P G startTemplateThread() M P G OS thread Processor (Logical) Goroutine runtime.LockOSThread()
- 22. LockOSThread() in go 1.10 M P G M P G Template thread M P G OS thread Processor (Logical) Goroutine runtime.LockOSThread()
- 23. Go runtime scheduler in 1.10 M P G M P G Template thread M P G OS thread Processor (Logical) Goroutine runtime.LockOSThread() M P G M P G
- 24. Template thread creation in Go Process eth0 net namespaces n Linux machine Go Process Template thread
- 25. Adding worker goroutines to host network namespace eth0 net namespaces n Linux machine Go Process Template thread
- 26. Summary • If creating / managing Linux network namespaces using Go, use Go version >= 1.10
- 27. Thank You!!!
- 28. runtime.LockOSThread() M P G M P G M P G G G M P G G G G G G Global queue Goroutine called LockOSThread() M P G OS thread Processor (Logical) Goroutine runtime.LockOSThread()
- 29. Docker runtime adopted Go ?? • Static compilation • Asynchronous primitives • Multi-arch builds • Faster development • Awesome Documentations
- 31. How to manage network namespaces with Go 1.10 and beyond ns := createNetNamespace() runtime.LockOSThread() defer runtime.UnlockOSThread() ns.Do(func(_ ns.NetNS) error { runtime.LockOSThread() cb() } If the goroutine here changes the state of the thread, let the thread exit with goroutine
- 32. Bonus feature • OS thread terminates if goroutine exits • runtime.LockOSThread() is nested. • UnlockOSThread must be called the same number of times in order to unlock the thread.
Editor's Notes
- #3: How Goroutines, threads, processors work in Go
- #7: How Goroutines, threads, processors work in Go
- #8: How Goroutines, threads, processors work in Go
- #9: How Goroutines, threads, processors work in Go
- #10: How Goroutines, threads, processors work in Go
- #11: How Goroutines, threads, processors work in Go
- #12: How Goroutines, threads, processors work in Go
- #17: How Goroutines, threads, processors work in Go
- #18: How Goroutines, threads, processors work in Go
- #25: How Goroutines, threads, processors work in Go
- #26: How Goroutines, threads, processors work in Go