NimbusSmart Scaling
Per-group time-based scaling schedules and predictive warmup for the Smart Scaling module.
The Smart Scaling module layers time-based schedules and predictive warmup on top of the fill-rate auto-scaling defined in group configs. Each group that should use Smart Scaling gets its own TOML file under config/modules/scaling/<Group>.toml.
Files are auto-generated on first start for any group that does not already have one. Reload with the reload console command.
Complete Example
[schedule]
enabled = true
timezone = "Europe/Berlin"
[[schedule.rules]]
name = "weekday-evening"
days = ["MON", "TUE", "WED", "THU", "FRI"]
from = "17:00"
to = "23:00"
min_instances = 3
max_instances = 12
[[schedule.rules]]
name = "weekend-allday"
days = ["SAT", "SUN"]
from = "10:00"
to = "23:59"
min_instances = 4
[warmup]
enabled = true
lead_time_minutes = 10[schedule]
Top-level schedule controls. When enabled = false, the whole file is ignored and the group falls back to the baseline min_instances / max_instances from its group config.
| Option | Type | Default | Description |
|---|---|---|---|
enabled | Boolean | true | Master switch for the schedule. Freshly generated files ship with enabled = false so a new group is never scheduled without opt-in. |
timezone | String | "Europe/Berlin" | IANA timezone ID used to evaluate from / to windows. Invalid values fall back to Europe/Berlin. |
[[schedule.rules]]
Zero or more ordered rules. Each rule raises (never lowers) the effective min_instances for its active window. If multiple rules overlap, the one with the highest min_instances wins.
| Option | Type | Default | Description |
|---|---|---|---|
name | String | required | Human-readable rule name. Used in logs, API responses (GET /api/scaling/schedules), and audit entries. |
days | List<String> | required | Day codes when the rule is active. Accepts 3-letter (MON) or full (MONDAY) names. Any day that fails to parse is silently dropped; a rule with no valid days is skipped. |
from | String | required | Window start, HH:MM (24h). Parsed with LocalTime.parse. |
to | String | required | Window end, HH:MM (24h). |
min_instances | Int | required | Minimum running instances while the rule is active. Stacks with — never undercuts — the group's base min_instances. |
max_instances | Int | unset | Optional cap applied while the rule is active. Leave unset to inherit the group's max_instances. |
The scheduler currently does not span midnight in a single rule. For a window like 22:00–02:00, split it into two rules (22:00–23:59 and 00:00–02:00) sharing the same min_instances.
[warmup]
Predictive warmup uses historical player counts to pre-start an instance before a scheduled min_instances bump takes effect. This hides the template-extract + JVM-start latency from players.
| Option | Type | Default | Description |
|---|---|---|---|
enabled | Boolean | true | Enable predictive warmup. When disabled, schedule bumps take effect exactly at from (cold start). |
lead_time_minutes | Int | 10 | Minutes before a rule's from time that warmup should begin pre-staging instances. Should be at least as long as your template's cold-start time. |
Warmup draws from the same warm-pool mechanism exposed by [group.scaling] warm_pool_size in the group config. Instances pre-started by warmup sit in the PREPARED state until the rule window opens.
Day Code Reference
| Input | Maps to |
|---|---|
MON, MONDAY | Monday |
TUE, TUESDAY | Tuesday |
WED, WEDNESDAY | Wednesday |
THU, THURSDAY | Thursday |
FRI, FRIDAY | Friday |
SAT, SATURDAY | Saturday |
SUN, SUNDAY | Sunday |
Codes are case-insensitive; whitespace is trimmed.
Disabling a Group
To fully opt a group out of Smart Scaling without deleting the file:
[schedule]
enabled = falseThe group will then behave per its [group.scaling] block in the group config.
Related
- Group Configuration —
[group.scaling]— fill-rate auto-scaling and warm pool size - Smart Scaling Guide
GET /api/scaling/schedules,GET /api/scaling/predictions/{group}— see API Reference