Skip to content

Latest commit

 

History

History
15 lines (12 loc) · 1.29 KB

systemd-rules.md

File metadata and controls

15 lines (12 loc) · 1.29 KB
Raw

Rules for using systemd reliably

These are coding style guidelines for our systemd units, based on bugs we've run into in production previously.

  • Requires=, Wants= are not allowed. If something that is depended upon fails, the thing depending on it will never try to be started again.
  • Before=, After= are discouraged. They are not strong guarantees, software needs to check that pre-requisites are up and working correctly
  • Restart=always should be used for all long-running services
  • Timer units need a non-zero OnBootSec (Some versions of systemd segfault with 0). We default to 5sec.
  • No using 'BindsTo' (Same reason as Requires/Wants)
  • All Exec and ExecStart lines must be trivial. If you're starting bash to do some computation, or a python interpreter with an embedded script which is doing something it will be rejected. Make a simple helper script. One-liners aren't cool to maintain.
  • Description= is used by the diagnostics service. Should be of the form $SERVICE_NAME: $DESCRIPTION
  • All new services must run as non-root User= must be set in their service files.
  • Do not add Environment= directly to systemd units. Use EnvironmentFile, and create the EnvironmentFile in dcos-config.yaml

Note some of the units do not follow these guidelines. They're being updated.