Chapter 06: Runtime Choices (VM, Container, systemd Service)

Word target: 3,500
Primary deliverable: Workload placement policy
Key diagrams: Runtime decision tree

Learning Goals

  • Select runtime model by workload characteristics and risk profile.
  • Keep host operations and application operations cleanly separated.
  • Define reproducible deployment contracts across runtimes.

MVP Lab Worksheet

  • Objective: Deploy one service in chosen runtime.
  • Starting state: Ubuntu node prepared.
  • Steps:
    1. Select service and runtime based on policy.
    2. Deploy with health check.
    3. Verify restart/recovery behavior.
  • Evidence: Service unit/compose file + health output.
  • Exit criteria: Service survives restart and reboot.
  • Rollback: Restore prior service method.

Advanced Lab Worksheet

  • Objective: Runtime comparison.
  • Starting state: MVP deployment complete.
  • Steps:
    1. Run same app via two runtime models.
    2. Compare performance, operability, and failure handling.
    3. Update placement policy.
  • Evidence: Benchmark + operational comparison matrix.
  • Exit criteria: Policy includes measurable thresholds.
  • Rollback: Standardize on baseline runtime.
Author Prompt

Include one anti-pattern case where containers were the wrong choice.