Logging and metrics in Cloud Foundry

This topic provides an overview of logging and metrics in VMware Tanzu Application Service for VMs (TAS for VMs). It includes information about logs and metrics sources and transport systems. It also lists products for viewing logs and metrics.

Accessing metrics

You must use a Cloud Foundry Command-Line Interface (cf CLI) plugin to access and view metrics directly from the command line. You can use either the Firehose plugin or the Log Cache plugin.

Accessing metrics using the Log Cache CLI Plug-in

To access metrics with the Log Cache plug-in:

cf login -a API-URL -u USERNAME -p PASSWORD

Where: ul>

API-URL is your API endpoint.
USERNAME is your username.
PASSWORD is your password.
Install the Log Cache CLI plugin by running:
```
cf install-plugin -r CF-Community "log-cache"
```
For more information, see log-cache in cf CLI Plugins on the Cloud Foundry website.
Run:
```
cf query 'METRIC-NAME{source_id="SOURCE-ID"}'
```
Where:
- METRIC-NAME is the name of the metric you want to view.
- SOURCE-ID is the source ID of the component for which you want to view metrics.
To find the source ID and metric name of the metric you want to view, see Key Performance Indicators and Key Capacity Scaling Indicators.

Accessing metrics using the Firehose Plug-in

To access metrics using the Firehose plugin:

Log in to the cf CLI by running:
```
cf login -a API-URL -u USERNAME -p PASSWORD
```
Where: * API-URL is your API endpoint. * USERNAME is your username. * PASSWORD is your password.
Install the Firehose cf CLI plugin by running:
```
cf install-plugin -r CF-Community "Firehose Plugin"
```
For more information, see Firehose plug-ins in cf CLI Plug-ins on the Cloud Foundry website.
Run:
```
cf nozzle -no-filter | grep SOURCE-ID | grep -i METRIC-NAME
```
Where:
- METRIC-NAME is the name of the metric you want to view.
- SOURCE-ID is the source ID of the component for which you want to view metrics.
For example:
```
cf nozzle -no-filter | grep bbs | grep -i ConvergenceLRPDuration
```
Because metrics are scraped at different intervals, it might take up to fifteen minutes for the Firehose to receive all metrics for the component. Run cf nozzle again until you have received a complete set of metrics for a component. For more information, see Firehose Architecture in Loggregator Architecture.

To find the source ID and metric name of the metric you want to view, see Key Performance Indicators and Key Capacity Scaling Indicators.

For more information about nozzles, see Nozzles in Logs, Metrics, and Nozzles in the Ops Manager Tile Developer Guide.

Sources for logs and metrics

There are two sources of TAS for VMs logs and metrics:

TAS for VMs platform components, such as a Diego Cell, MySQL Server, or Cloud Controller
Apps and app containers deployed on TAS for VMs

The following table describes the data included in logs and metrics from each source:

Source	Logs Data	Metrics Data
Platform components	Logs from TAS for VMs components	Health metrics from BOSH-deployed VMs¹ Platform metrics from TAS for VMs components. For example, Diego Cell capacity remaining and Gorouter throughput. Metrics for any service tile that self-publishes to the Loggregator Firehose. For example, Redis and MySQL.
Apps and app containers	Logs from apps²	Container metrics³ Custom app metrics⁴

¹For more information about using the BOSH Health Monitor to collect health metrics on VMs, see Configuring a Monitoring System.

²For more information about app logging, see App Logging in TAS for VMs.

⁴For more information about configuring an app to stream custom metrics to Loggregator, see Metric Registrar and Custom App Metrics.

Transport Systems for Logs and Metrics

The following transport systems deliver logs and metrics from their source to an observability product for viewing:

Loggregator: Loggregator is the transport system for both logs and metrics on apps deployed on TAS for VMs, as well as metrics on TAS for VMs platform components.

For more information about the Loggregator system, including Loggregator architecture and components, see Loggregator Architecture and for the types of envelopes being transported in Loggregator, see Envelope Types.

rsyslogd on TAS for VMs component VMs: rsyslogd is the transport system for TAS for VMs component logs. Users can configure rsyslogd to transport component logs to a third-party syslog server.

The table below lists the transport system for logs and metrics on TAS for VMs platform components and apps:

Source	Logs Transport System	Metrics Transport System
Platform components	rsyslogd on TAS for VMs component VMs	Loggregator
Apps	Loggregator	Loggregator

Viewing logs and metrics

The table below lists the products and tools for viewing TAS for VMs logs and metrics:

Source	Products and Tools for Viewing Logs	Products and Tools for Viewing Metrics
Platform components	To view system logs from TAS for VMs components, configure rsyslogd to transport logs to a third-party product.	You can use the following products or tools to view platform component and VM metrics: Loggregator Firehose CLI Plug in. See Installing the Loggregator Firehose plug-in for CLI. Loggregator Log Cache CLI plug-in. See Cloud Foundry Community cf CLI plug-ins. Healthwatch. See Healthwatch for VMware Tanzu.
Apps	You can use the following products or tools to view app logs: cf CLI cf logs command. See Cloud Foundry CLI Reference Guide. Apps Manager. See Managing Apps and Service Instances Using Apps Manager. Syslog forwarding. See Streaming App Logs to Log Management Services. Loggregator Firehose CLI plug-in. See Installing the Loggregator Firehose plug-in for CLI. Loggregator Log Cache CLI plug-in. See Cloud Foundry Community cf CLI plug-ins.	You can use the following products or tools to view app metrics: Loggregator Firehose CLI plug-in. See Installing the Loggregator Firehose plug-in for CLI. Loggregator Log Cache CLI plug-in. See Cloud Foundry Community cf CLI plug-ins. App Metrics. See the App Metrics documentation.