Scale & restart

Three commands cover most lifecycle work: scale, restart, stop. They wrap the same underlying reconciler, so they’re safe to chain.

Immediate scale

rune scale api 5

The reconciler creates or destroys instances until 5 are running and healthy. The CLI blocks until rollout completes (or the timeout — --timeout=5m by default).

Don’t wait:

rune scale api 5 --no-wait

Gradual scale

When ramping a stateful or memory-hungry service, step up:

rune scale api 10 --mode=gradual --step=2 --interval=30s

This adds 2 instances every 30 seconds until you hit 10. If any step fails health checks, the operation aborts.

Flag	Default	Notes
--mode	immediate	immediate or gradual.
--step	1	Instances added/removed per step.
--interval	30s	Time between steps.
--rollback-on-fail	true	Revert to previous scale on health failure.

Restart

restart scales to 0 then back to the previous scale:

rune restart api

Use it after editing a configmap or rotating a secret — mounted files don’t hot-reload, but a restart picks them up.

For zero-downtime rolling restarts, use a runeset upgrade with rolling update settings (Release 2 — not yet available; for now, restart is a stop-the-world operation per service).

Stop

rune stop api

Stops without deleting — desired scale becomes 0, the spec stays. Bring it back with rune scale api N or another cast.

Failure handling

By default, scale operations roll back on health failure. To pin the new scale even if some instances fail to come up:

rune scale api 10 --rollback-on-fail=false

Use this only when you know the service is fine and you’d rather see partial progress than revert.

Inspecting a scale operation

rune get service api -o yaml | grep -A5 status

Status fields you’ll see during a scale:

• desiredReplicas — what you asked for.
• readyReplicas — instances passing readiness.
• currentReplicas — instances that exist (may not be ready).
• lastScaleAt, lastScaleReason.

Common patterns

# Drain a service for maintenance
rune stop api

# Bring it back to 3
rune scale api 3

# Restart after rotating a secret
rune restart api

# Slow ramp of a worker pool
rune scale workers 50 --mode=gradual --step=5 --interval=1m

Anti-patterns

• Scaling instead of restarting. rune scale api 0 && rune scale api 3 works but is awkward — use rune restart api.
• Forgetting --no-wait in CI scripts when you don’t actually want to block.
• Setting --rollback-on-fail=false by default to “make scaling faster.” If health is flapping, you want the rollback. Fix the probes.