Structural and semantic deficiencies in the systemd architecture, another jeremiad | V.R.

Some dude using the self-asserted identity token V.R.; Structural and semantic deficiencies in the systemd architecture for real-world service management, a technical treatise; In Some Blog; 2015-10-11.

tl;dr → A jeremiad; 8100 words; systemd is bad, he doesn’t like it.

Mentions

His point, and he does have one, is that
  • There are simply too many notes
  • And there is insufficient reference to the priors in the art
  • Oh! and it’s full of bugs! Lots! Of! Bugs!
Not shown:
  • the way forward
  • a complete viable alternative
    • complete in a technical sense of solving the problem
    • complete in a cultural sense of having an adiabatic transition to the new phase
  • that sticking with tangled masses of stylized /bin/sh (ahem, the SysV initscripts), better, possible or even an option.  That system worked “well enough ” that you knew getting away from it would be messy.
And yet
  • Mel Conway’s Law is iron
  • Lennart Poettering & Kay Sievers operate as a single organization.
  • Therefore systemd evolves onward as a single-process central-element architectural solution to the problems it addresses; all-in or out.
    Similar to the monolithic_macrokernel-vs-microkernel culture wars of the ’90s.  The Linux kernel is … go on, say it.

Outline

  • Preface and disclaimer (!)
  • Everything is a Unit (but it doesn’t mean a lot)
  • Job queuing
  • The transaction manager
  • To live is to depend
  • Every problem can be solved by a layer of indirection
  • Bus APIs, connections and object interface duplication
  • cgroup writing
  • Parsing in critical paths
  • Non-generic fd-holding and socket preopening
  • Inexpressive unit file options
  • Imbalance between promoting laziness or eagerness
  • Targets over milestones for synchronization
  • The (system-specific) problem of readiness notification
  • Intertwining of global system and service state
  • journald, central I/O bottleneck
  • In conclusion

Referenced

In order of appearance in the piece

Background

Unreferenced

And for a guy interest in respect for the elders who have trod the trails before stand silent

Via: backfill.