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docs: follow-up for 197d3cdd74 (#2766)
Signed-off-by: hagen1778 <roman@victoriametrics.com>
This commit is contained in:
Roman Khavronenko
GitHub
parent
197d3cdd74
commit
75dd7542e5
2 changed files with 60 additions and 24 deletions
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@ -402,6 +402,36 @@ Check how to replace it with [cluster VictoriaMetrics](#cluster-victoriametrics)
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#### Downsampling and aggregation via vmalert
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#### Downsampling and aggregation via vmalert
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`vmalert` can't modify existing data. But it can run arbitrary PromQL/MetricsQL queries
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via [recording rules](#recording-rules) and backfill results to the configured `-remoteWrite.url`.
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This ability allows to aggregate data. For example, the following rule will calculate the average value for
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metric `http_requests` on the `5m` interval:
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```yaml
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- record: http_requests:avg5m
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expr: avg_over_time(http_requests[5m])
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```
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Every time this rule will be evaluated, `vmalert` will backfill its results as a new time series `http_requests:avg5m`
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to the configured `-remoteWrite.url`.
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`vmalert` executes rules with specified interval (configured via flag `-evaluationInterval`
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or as [group's](#groups) `interval` param). The interval helps to control "resolution" of the produced series.
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This ability allows to downsample data. For example, the following config will execute the rule only once every `5m`:
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```yaml
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groups:
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- name: my_group
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interval: 5m
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rules:
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- record: http_requests:avg5m
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expr: avg_over_time(http_requests[5m])
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```
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Ability of `vmalert` to be configured with different `datasource.url` and `remoteWrite.url` allows
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reading data from one data source and backfilling results to another. This helps to build a system
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for aggregating and downsampling the data.
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The following example shows how to build a topology where `vmalert` will process data from one cluster
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The following example shows how to build a topology where `vmalert` will process data from one cluster
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and write results into another. Such clusters may be called as "hot" (low retention,
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and write results into another. Such clusters may be called as "hot" (low retention,
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high-speed disks, used for operative monitoring) and "cold" (long term retention,
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high-speed disks, used for operative monitoring) and "cold" (long term retention,
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@ -417,18 +447,6 @@ or reducing resolution) and push results to "cold" cluster.
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-remoteWrite.url=http://aggregated-cluster-vminsert:8480/insert/0/prometheus # vminsert addr to persist recording rules results
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-remoteWrite.url=http://aggregated-cluster-vminsert:8480/insert/0/prometheus # vminsert addr to persist recording rules results
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```
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```
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`vmalert` passes the configuration [recording rules](https://docs.victoriametrics.com/vmalert.html#recording-rules). These rules execute arbitrary MetricsQL expression and write the received result back to remote write destination.
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For example, for `downsampling` of the total number of requests within five minutes, the configuration file can be as follows
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```
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groups:
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- name: downsampling
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rules:
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- record: requests:avg5m
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expr: avg_over_time(my_requests_total[5m])
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```
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<img alt="vmalert multi cluster" src="vmalert_multicluster.png">
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<img alt="vmalert multi cluster" src="vmalert_multicluster.png">
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Please note, [replay](#rules-backfilling) feature may be used for transforming historical data.
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Please note, [replay](#rules-backfilling) feature may be used for transforming historical data.
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@ -406,6 +406,36 @@ Check how to replace it with [cluster VictoriaMetrics](#cluster-victoriametrics)
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#### Downsampling and aggregation via vmalert
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#### Downsampling and aggregation via vmalert
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`vmalert` can't modify existing data. But it can run arbitrary PromQL/MetricsQL queries
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via [recording rules](#recording-rules) and backfill results to the configured `-remoteWrite.url`.
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This ability allows to aggregate data. For example, the following rule will calculate the average value for
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metric `http_requests` on the `5m` interval:
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```yaml
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- record: http_requests:avg5m
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expr: avg_over_time(http_requests[5m])
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```
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Every time this rule will be evaluated, `vmalert` will backfill its results as a new time series `http_requests:avg5m`
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to the configured `-remoteWrite.url`.
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`vmalert` executes rules with specified interval (configured via flag `-evaluationInterval`
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or as [group's](#groups) `interval` param). The interval helps to control "resolution" of the produced series.
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This ability allows to downsample data. For example, the following config will execute the rule only once every `5m`:
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```yaml
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groups:
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- name: my_group
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interval: 5m
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rules:
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- record: http_requests:avg5m
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expr: avg_over_time(http_requests[5m])
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```
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Ability of `vmalert` to be configured with different `datasource.url` and `remoteWrite.url` allows
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reading data from one data source and backfilling results to another. This helps to build a system
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for aggregating and downsampling the data.
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The following example shows how to build a topology where `vmalert` will process data from one cluster
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The following example shows how to build a topology where `vmalert` will process data from one cluster
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and write results into another. Such clusters may be called as "hot" (low retention,
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and write results into another. Such clusters may be called as "hot" (low retention,
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high-speed disks, used for operative monitoring) and "cold" (long term retention,
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high-speed disks, used for operative monitoring) and "cold" (long term retention,
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@ -421,18 +451,6 @@ or reducing resolution) and push results to "cold" cluster.
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-remoteWrite.url=http://aggregated-cluster-vminsert:8480/insert/0/prometheus # vminsert addr to persist recording rules results
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-remoteWrite.url=http://aggregated-cluster-vminsert:8480/insert/0/prometheus # vminsert addr to persist recording rules results
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```
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```
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`vmalert` passes the configuration [recording rules](https://docs.victoriametrics.com/vmalert.html#recording-rules). These rules execute arbitrary MetricsQL expression and write the received result back to remote write destination.
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For example, for `downsampling` of the total number of requests within five minutes, the configuration file can be as follows
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```
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groups:
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- name: downsampling
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rules:
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- record: requests:avg5m
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expr: avg_over_time(my_requests_total[5m])
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```
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<img alt="vmalert multi cluster" src="vmalert_multicluster.png">
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<img alt="vmalert multi cluster" src="vmalert_multicluster.png">
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Please note, [replay](#rules-backfilling) feature may be used for transforming historical data.
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Please note, [replay](#rules-backfilling) feature may be used for transforming historical data.
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