A service may omit its state, so unassigning an uplink module never stops the machine's network manager (hq ADR 0117)

internal/apply/plan.go

@@ -80,6 +80,9 @@ func Plan(d *declaration.Declaration, known store.State, origin string) []Step {
 	for _, orphan := range known.Orphans(declared, origin) {
 		step := Step{Verb: "remove", Type: orphan.Type, ID: orphan.ID, Target: orphan.Target,
 			Why: "recorded here and no longer declared"}
+		if orphan.Stateless {
+			step.Verb, step.Why = "forget", "no longer declared; its unit's state was never the mesh's and is left as it is"
+		}
 		if d.Adoption == nil && strings.HasPrefix(orphan.ID, declaration.AdoptionPrefix) {
 			step.Why = "what protected this node while adopted; removed last, once everything else applied"
 			protecting = append(protecting, step)
@@ -139,11 +142,9 @@ func planned(r declaration.Resource, d *declaration.Declaration, known store.Sta
 				}
 			}
 		}
-		// A file written into replaces nothing that was found, so it is never held (ADR 0102).
-		into := false
-		if f, ok := r.(*declaration.File); ok && f.Into != "" {
-			into = true
-		}
+		// A file written into, or a service whose lifecycle is the machine's, replaces nothing that
+		// was found, so it is never held (ADR 0102, ADR 0117).
+		into := replacesNothing(r)
 		h, held := known.HeldAt(r.Identity())
 		module, untaken := d.Adoption.UntakenModuleOf(r.Identity())
 		switch {
@@ -182,6 +183,12 @@ func planned(r declaration.Resource, d *declaration.Declaration, known store.Sta
 		return step
 	}
 
+	if svc, ok := r.(*declaration.Service); ok && svc.Stateless() {
+		// Nothing is created: the unit and whether it runs are the machine's (novox/hq ADR 0117).
+		step.Verb, step.Why = "check", "its lifecycle is the machine's; reloaded or restarted only if "+
+			"running when what it reflects changes"
+		return step
+	}
 	was, recorded := known.Find(r.Identity())
 	if !recorded {
 		step.Verb, step.Why = "create", "no record of it on this node"