Resource Considerations
This document describes resource considerations and limitations to be taken into account when provisioning and operating a9s Prometheus Service Instances.
The resource requirements of a Service Instance depend on the Template selected for its Service Plan. Each Template defines the topology (number of nodes) and the set of colocated processes. Templates that provide logging require a higher-memory VM type and more ephemeral disk than Templates without logging.
The Platform Operator must define matching vm_type and persistent_disk_type entries in the BOSH Cloud Config and
reference them from the Service Plan configuration. For guidance on Service Plans and Templates, see Service Plans
and Available Templates.
For guidance on Service Plans and Templates, see Service Plans and Available Templates.
Template Requirements
The resource requirements of a Service Instance depend on the Template selected for its Service Plan. The small,
medium, and large labels used for VM type and persistent disk type in the tables below refer to the example Cloud
Config entries defined in Update the Cloud Config.
The following table lists resource requirements per VM, as well as totals across all nodes of a Service Instance.
- Per VM
- Totals
| Template name | VM Role | Nodes | vCPUs | Logging | Min. RAM | Min. Persistent Disk | Min. Ephemeral Disk | Example VM Type | Example Persistent Disk Type |
|---|---|---|---|---|---|---|---|---|---|
prometheus2-grafana10-single | Prometheus | 1 | 2 | No | ≥ 4 GB | 4 GB | 5 GB | small | small |
| Grafana | 1 | 2 | No | ≥ 4 GB | 4 GB | 5 GB | small | small | |
| Alertmanager | 1 | 2 | No | ≥ 4 GB | 4 GB | 5 GB | small | small | |
prometheus3-grafana13-single | Prometheus | 1 | 2 | No | ≥ 4 GB | 4 GB | 5 GB | small | small |
| Grafana | 1 | 2 | No | ≥ 4 GB | 4 GB | 5 GB | small | small | |
| Alertmanager | 1 | 2 | No | ≥ 4 GB | 4 GB | 5 GB | small | small |
| Template name | Nodes | vCPUs | Logging | Min. RAM | Min. Persistent Disk | Min. Ephemeral Disk |
|---|---|---|---|---|---|---|
prometheus2-grafana10-single | 3 | 6 ‡ | No | ≥ 12 GB ‡ | 12 GB ‡ | 15 GB ‡ |
prometheus3-grafana13-single | 3 | 6 ‡ | No | ≥ 12 GB ‡ | 12 GB ‡ | 15 GB ‡ |
| ‡ Each total is the sum of that column's value across all three VMs of the Template (see the Per VM tab for the breakdown by role), not the value for a single VM. | ||||||
The Prometheus VM stores time-series metrics on persistent disk using the Prometheus Time Series Database; disk usage
grows linearly with scrape interval, metric cardinality, and retention period. The default retention period is 15 days.
The small disk type (4 GB) is a minimum starting point for the Prometheus VM; disk sizing must be revisited whenever
the retention period or the set of scrape targets changes.