---
title: Scheduler
weight: 3
menu:
docs:
parent: "vmanomaly-components"
weight: 3
aliases:
- /anomaly-detection/components/scheduler.html
---
Scheduler defines how often to run and make inferences, as well as what timerange to use to train the model.
Is specified in `scheduler` section of a config for VictoriaMetrics Anomaly Detection.
> **Note: Starting from [v1.11.0](https://docs.victoriametrics.com/anomaly-detection/changelog/#v1110) scheduler section in config supports multiple schedulers via aliasing. <br>Also, `vmanomaly` expects scheduler section to be named `schedulers`. Using old (flat) format with `scheduler` key is deprecated and will be removed in future versions.**
```yaml
schedulers:
scheduler_periodic_1m:
# class: "periodic" # or class: "scheduler.periodic.PeriodicScheduler" until v1.13.0 with class alias support)
infer_every: "1m"
fit_every: "2m"
fit_window: "3h"
scheduler_periodic_5m:
# class: "periodic" # or class: "scheduler.periodic.PeriodicScheduler" until v1.13.0 with class alias support)
infer_every: "5m"
fit_every: "10m"
fit_window: "3h"
...
```
Old-style configs (< [1.11.0](https://docs.victoriametrics.com/anomaly-detection/changelog/#v1110))
```yaml
scheduler:
# class: "periodic" # or class: "scheduler.periodic.PeriodicScheduler" until v1.13.0 with class alias support)
infer_every: "1m"
fit_every: "2m"
fit_window: "3h"
...
```
will be **implicitly** converted to
```yaml
schedulers:
default_scheduler: # default scheduler alias added, for backward compatibility
class: "scheduler.periodic.PeriodicScheduler"
infer_every: "1m"
fit_every: "2m"
fit_window: "3h"
...
```
## Parameters
`class`: str, default=`"scheduler.periodic.PeriodicScheduler"`,
options={`"scheduler.periodic.PeriodicScheduler"`, `"scheduler.oneoff.OneoffScheduler"`, `"scheduler.backtesting.BacktestingScheduler"`}
- `"scheduler.periodic.PeriodicScheduler"`: periodically runs the models on new data. Useful for consecutive re-trainings to counter [data drift](https://www.datacamp.com/tutorial/understanding-data-drift-model-drift) and model degradation over time.
- `"scheduler.oneoff.OneoffScheduler"`: runs the process once and exits. Useful for testing.
- `"scheduler.backtesting.BacktestingScheduler"`: imitates consecutive backtesting runs of OneoffScheduler. Runs the process once and exits. Use to get more granular control over testing on historical data.
> **Note**: starting from [v1.13.0](https://docs.victoriametrics.com/anomaly-detection/changelog/#v1130), class aliases are supported, so `"scheduler.periodic.PeriodicScheduler"` can be substituted to `"periodic"`, `"scheduler.oneoff.OneoffScheduler"` - to `"oneoff"`, `"scheduler.backtesting.BacktestingScheduler"` - to `"backtesting"`
**Depending on selected class, different parameters should be used**
## Periodic scheduler
### Parameters
For periodic scheduler parameters are defined as differences in times, expressed in difference units, e.g. days, hours, minutes, seconds.
Examples: `"50s"`, `"4m"`, `"3h"`, `"2d"`, `"1w"`.
<table class="params">
<thead>
<tr>
<th></th>
<th>Time granularity</th>
</tr>
</thead>
<tbody>
<tr>
<td>s</td>
<td>seconds</td>
</tr>
<tr>
<td>m</td>
<td>minutes</td>
</tr>
<tr>
<td>h</td>
<td>hours</td>
</tr>
<tr>
<td>d</td>
<td>days</td>
</tr>
<tr>
<td>w</td>
<td>weeks</td>
</tr>
</tbody>
</table>
<table class="params">
<thead>
<tr>
<th>Parameter</th>
<th>Type</th>
<th>Example</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>
`fit_window`
</td>
<td>str</td>
<td>
`"14d"`
</td>
<td>What time range to use for training the models. Must be at least 1 second.</td>
</tr>
<tr>
<td>
`infer_every`
</td>
<td>str</td>
<td>
`"1m"`
</td>
<td>How often a model will write its conclusions on newly added data. Must be at least 1 second.</td>
</tr>
<tr>
<td>
`fit_every`
</td>
<td>str, Optional</td>
<td>
`"1h"`
</td>
<td>
How often to completely retrain the models. If missing value of `infer_every` is used and retrain on every inference run.
</td>
</tr>
</tbody>
</table>
### Periodic scheduler config example
```yaml
schedulers:
periodic_scheduler_alias:
class: "periodic"
# (or class: "scheduler.periodic.PeriodicScheduler" until v1.13.0 with class alias support)
fit_window: "14d"
infer_every: "1m"
fit_every: "1h"
```
This part of the config means that `vmanomaly` will calculate the time window of the previous 14 days and use it to train a model. Every hour model will be retrained again on 14 days’ data, which will include + 1 hour of new data. The time window is strictly the same 14 days and doesn't extend for the next retrains. Every minute `vmanomaly` will produce model inferences for newly added data points by using the model that is kept in memory at that time.
## Oneoff scheduler
### Parameters
For Oneoff scheduler timeframes can be defined in Unix time in seconds or ISO 8601 string format.
ISO format supported time zone offset formats are:
* Z (UTC)
* ±HH:MM
* ±HHMM
* ±HH
If a time zone is omitted, a timezone-naive datetime is used.
### Defining fitting timeframe
<table class="params">
<thead>
<tr>
<th>Format</th>
<th>Parameter</th>
<th>Type</th>
<th>Example</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>ISO 8601</td>
<td>
`fit_start_iso`
</td>
<td>str</td>
<td>
`"2022-04-01T00:00:00Z", "2022-04-01T00:00:00+01:00", "2022-04-01T00:00:00+0100", "2022-04-01T00:00:00+01"`
</td>
<td rowspan=2>Start datetime to use for training a model. ISO string or UNIX time in seconds.</td>
</tr>
<tr>
<td>UNIX time</td>
<td>
`fit_start_s`
</td>
<td>float</td>
<td>1648771200</td>
</tr>
<tr>
<td>ISO 8601</td>
<td>
`fit_end_iso`
</td>
<td>str</td>
<td>
`"2022-04-10T00:00:00Z", "2022-04-10T00:00:00+01:00", "2022-04-10T00:00:00+0100", "2022-04-10T00:00:00+01"`
</td>
<td rowspan=2>End datetime to use for training a model. Must be greater than
`fit_start_*`
. ISO string or UNIX time in seconds.</td>
</tr>
<tr>
<td>UNIX time</td>
<td>
`fit_end_s`
</td>
<td>float</td>
<td>1649548800</td>
</tr>
</tbody>
</table>
### Defining inference timeframe
<table class="params">
<thead>
<tr>
<th>Format</th>
<th>Parameter</th>
<th>Type</th>
<th>Example</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>ISO 8601</td>
<td>
`infer_start_iso`
</td>
<td>str</td>
<td>
`"2022-04-11T00:00:00Z", "2022-04-11T00:00:00+01:00", "2022-04-11T00:00:00+0100", "2022-04-11T00:00:00+01"`
</td>
<td rowspan=2>Start datetime to use for a model inference. ISO string or UNIX time in seconds.</td>
</tr>
<tr>
<td>UNIX time</td>
<td>
`infer_start_s`
</td>
<td>float</td>
<td>1649635200</td>
</tr>
<tr>
<td>ISO 8601</td>
<td>
`infer_end_iso`
</td>
<td>str</td>
<td>
`"2022-04-14T00:00:00Z", "2022-04-14T00:00:00+01:00", "2022-04-14T00:00:00+0100", "2022-04-14T00:00:00+01"`
</td>
<td rowspan=2>End datetime to use for a model inference. Must be greater than
`infer_start_*`
. ISO string or UNIX time in seconds.</td>
</tr>
<tr>
<td>UNIX time</td>
<td>
`infer_end_s`
</td>
<td>float</td>
<td>1649894400</td>
</tr>
</tbody>
</table>
### ISO format scheduler config example
```yaml
schedulers:
oneoff_scheduler_alias:
class: "oneoff"
# (or class: "scheduler.oneoff.OneoffScheduler" until v1.13.0 with class alias support)
fit_start_iso: "2022-04-01T00:00:00Z"
fit_end_iso: "2022-04-10T00:00:00Z"
infer_start_iso: "2022-04-11T00:00:00Z"
infer_end_iso: "2022-04-14T00:00:00Z"
```
### UNIX time format scheduler config example
```yaml
schedulers:
oneoff_scheduler_alias:
class: "oneoff"
# (or class: "scheduler.oneoff.OneoffScheduler" until v1.13.0 with class alias support)
fit_start_s: 1648771200
fit_end_s: 1649548800
infer_start_s: 1649635200
infer_end_s: 1649894400
```
## Backtesting scheduler
### Parameters
As for [Oneoff scheduler](#oneoff-scheduler), timeframes can be defined in Unix time in seconds or ISO 8601 string format.
ISO format supported time zone offset formats are:
* Z (UTC)
* ±HH:MM
* ±HHMM
* ±HH
If a time zone is omitted, a timezone-naive datetime is used.
### Parallelization
<table class="params">
<thead>
<tr>
<th>Parameter</th>
<th>Type</th>
<th>Example</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>
`n_jobs`
</td>
<td>int</td>
<td>
`1`
</td>
<td>
Allows *proportionally faster (yet more resource-intensive)* evaluations of a config on historical data. Default value is 1, that implies *sequential* execution. Introduced in [v1.13.0](https://docs.victoriametrics.com/anomaly-detection/changelog/#v1130)
</td>
</tr>
</tbody>
</table>
### Defining overall timeframe
This timeframe will be used for slicing on intervals `(fit_window, infer_window == fit_every)`, starting from the *latest available* time point, which is `to_*` and going back, until no full `fit_window + infer_window` interval exists within the provided timeframe.
<table class="params">
<thead>
<tr>
<th>Format</th>
<th>Parameter</th>
<th>Type</th>
<th>Example</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>ISO 8601</td>
<td>
`from_iso`
</td>
<td>str</td>
<td>
`"2022-04-01T00:00:00Z", "2022-04-01T00:00:00+01:00", "2022-04-01T00:00:00+0100", "2022-04-01T00:00:00+01"`
</td>
<td rowspan=2>Start datetime to use for backtesting.</td>
</tr>
<tr>
<td>UNIX time</td>
<td>
`from_s`
</td>
<td>float</td>
<td>1648771200</td>
</tr>
<tr>
<td>ISO 8601</td>
<td>
`to_iso`
</td>
<td>str</td>
<td>
`"2022-04-10T00:00:00Z", "2022-04-10T00:00:00+01:00", "2022-04-10T00:00:00+0100", "2022-04-10T00:00:00+01"`
</td>
<td rowspan=2>End datetime to use for backtesting. Must be greater than
`from_start_*`
</td>
</tr>
<tr>
<td>UNIX time</td>
<td>
`to_s`
</td>
<td>float</td>
<td>1649548800</td>
</tr>
</tbody>
</table>
### Defining training timeframe
The same *explicit* logic as in [Periodic scheduler](#periodic-scheduler)
<table class="params">
<thead>
<tr>
<th>Format</th>
<th>Parameter</th>
<th>Type</th>
<th>Example</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>ISO 8601</td>
<td rowspan=2>
`fit_window`
</td>
<td rowspan=2>str</td>
<td>
`"PT1M", "P1H"`
</td>
<td rowspan=2>What time range to use for training the models. Must be at least 1 second.</td>
</tr>
<tr>
<td>Prometheus-compatible</td>
<td>
`"1m", "1h"`
</td>
</tr>
</tbody>
</table>
### Defining inference timeframe
In `BacktestingScheduler`, the inference window is *implicitly* defined as a period between 2 consecutive model `fit_every` runs. The *latest* inference window starts from `to_s` - `fit_every` and ends on the *latest available* time point, which is `to_s`. The previous periods for fit/infer are defined the same way, by shifting `fit_every` seconds backwards until we get the last full fit period of `fit_window` size, which start is >= `from_s`.
<table class="params">
<thead>
<tr>
<th>Format</th>
<th>Parameter</th>
<th>Type</th>
<th>Example</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>ISO 8601</td>
<td rowspan=2>
`fit_every`
</td>
<td rowspan=2>str</td>
<td>
`"PT1M", "P1H"`
</td>
<td rowspan=2>What time range to use previously trained model to infer on new data until next retrain happens.</td>
</tr>
<tr>
<td>Prometheus-compatible</td>
<td>
`"1m", "1h"`
</td>
</tr>
</tbody>
</table>
### ISO format scheduler config example
```yaml
schedulers:
backtesting_scheduler_alias:
class: "backtesting"
# (or class: "scheduler.backtesting.BacktestingScheduler" until v1.13.0 with class alias support)
from_iso: '2021-01-01T00:00:00Z'
to_iso: '2021-01-14T00:00:00Z'
fit_window: 'P14D'
fit_every: 'PT1H'
n_jobs: 1 # default = 1 (sequential), set it up to # of CPUs for parallel execution
```
### UNIX time format scheduler config example
```yaml
schedulers:
backtesting_scheduler_alias:
class: "backtesting"
# (or class: "scheduler.backtesting.BacktestingScheduler" until v1.13.0 with class alias support)
from_s: 167253120
to_s: 167443200
fit_window: '14d'
fit_every: '1h'
n_jobs: 1 # default = 1 (sequential), set it up to # of CPUs for parallel execution
```