Container Metrics

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This topic describes the metrics that are emitted by all containers managed by VMware Tanzu Application Service for VMs (TAS for VMs) and its scheduling system, Diego.

App metrics include the container metrics described below, plus any custom app metrics that developers create.

Diego Container Metrics

Diego containers emit the following resource usage metrics for their app instance (AI). Each metric is averaged over and emitted every 15 seconds.

The following table describes all Diego container metrics:

Metric Description Unit
CpuPercentage CPU time used by AI as a percentage of a single CPU core.

This is usually no greater than 100% * the number of vCPUs on the host Diego cell, but it may be more due to discrepancies in measurement timing.		 float64
AbsoluteCPUEntitlement CPU time that the AI was entitled to use.

At minimum, the CPU time that a Diego cell provides an AI is min(app memory, 8 GB) * (Diego cell vCPUs/Diego cell memory) * 100%.

The platform operator can provide the Diego cell vCPUs/memory ratio to developers.
If a Diego cell is not at capacity or if other workloads on it are idle, the cell can provide more than the minimum CPU.		 uint64
AbsoluteCPUUsage CPU time used by AI.

AbsoluteCPUUsage / AbsoluteCPUEntitlement calculates a 0-100% range of AI usage per entitlement.		 uint64
MemoryBytes RAM memory used by AI, in MB. uint64
MemoryBytesQuota RAM memory available, in GB. uint64
DiskBytes Disk space used by AI, in MB. uint64
DiskBytesQuota Disk space available, in GB. uint64
ContainerAge Age of container, in nanoseconds. uint64

Loggregator v1: Most of the container metrics are emitted in a ContainerMetric envelope. The AbsoluteCPUEntitlement, AbsoluteCPUUsage, and ContainerAge container metrics are emitted as separate ValueMetric envelopes.

Loggregator v2: All container metrics are emitted in gauge envelopes. The AbsoluteCPUEntitlement, AbsoluteCPUUsage, and ContainerAge container metrics are emitted in a separate envelope to the other container metrics.

Retrieve Container Metrics from the cf CLI

You can use Cloud Foundry command-line interface (cf CLI) commands to return container metrics.

Retrieve CPU, Memory, and Disk Metrics

To retrieve CPU, memory, and disk metrics for all instances of an app:

  1. Run the command cf app APP-NAME.

The command output lists Diego container metric values as follows:

Label in Output Metrics listed, as described in Diego Container Metrics, above
cpu CpuPercentage
memory MemoryBytes of MemoryBytesQuota
disk DiskBytes of DiskBytesQuota

For example:

$ cf app dora-example
Showing health and status for app dora-example in org o / space s as admin...

name:              dora-example
requested state:   started
routes:            dora-example.bosh-lite.com
last uploaded:     Fri 05 Apr 10:41:21 PDT 2019
stack:             cflinuxfs3
buildpacks:        ruby

type:           web
instances:      1/1
memory usage:   256M
     state     since                  cpu    memory          disk          details
#0   running   2019-04-05T17:41:31Z   0.4%   39.5M of 256M   89.9M of 1G

Retrieve CPU Entitlement Metrics (Experimental)

To see app instance AbsoluteCPUEntitlement metrics from the command line:

  1. Install the CPU Entitlement Plugin from cpu-entitlement-plugin in GitHub.

  2. Run the command cf cpu-entitlement APP-NAME.

For example:

$ cf cpu-entitlement dora-example
Note: This feature is experimental.
Showing CPU usage against entitlement for app dora-example in org example-org / space example-org-staging as dora@example.com ...
​
     avg usage   curr usage
#0   1.62%       1.66%
#1   2.93%       3.09%
#2   2.51%       2.62%
​