Here you can learn about the metrics that are emitted by all containers managed by VMware Tanzu Application Service for VMs (TAS for VMs) and its scheduling system, Diego.

Application metrics include the container metrics, and any custom application metrics that developers create.

Diego container metrics

Diego containers emit resource usage metrics for the application instance. Diego averages and emits each metric every 15 seconds.

The following table describes all Diego container metrics:

Metric Description Unit
cpu CPU time used by an app instance 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 might be more due to discrepancies in measurement timing.		 float64
cpu_entitlement CPU time used by an app instance as a percentage of its CPU entitlement.

At minimum, the CPU time that a Diego Cell allocates to an app instance is min(app memory, 8 GB) * (Diego cell vCPUs/Diego cell memory) * 100%. The operator of your TAS for VMs deployment can provide the vCPUs/memory ratio of the Diego Cell to developers.
If a Diego Cell is not already working at capacity, or if other workloads on the Diego Cell are idle, the Diego Cell can allocate more than the minimum amount of CPU time to an app instance.		 float64
memory The amount of RAM memory in bytes that an app instance has used. uint64
memory_quota The amount of RAM memory in bytes that is available for an app instance to use. float64
disk The amount of disk space in bytes that an app instance has used. float64
disk_quota The amount of disk space in bytes that is available for an app instance to use. float64
container_age The age in nanoseconds of the Diego container. float64
log_rate The current log rate in bytes per second for an app instance. float64
log_rate_limit The log rate limit in bytes per second for an app instance. float64
rx_bytes Received network traffic in bytes for an app instance. uint64
tx_bytes Transmitted network traffic in bytes for an app instance. uint64

The operator of your TAS for VMs deployment can enable it to emit the following additional, deprecated container metrics:

Metric Description Unit
absolute_entitlement The amount of CPU time that a Diego Cell has allocated to an app instance, in nanoseconds.

At minimum, the CPU time that a Diego Cell allocates to an app instance is min(app memory, 8 GB) * (Diego cell vCPUs/Diego cell memory) * 100%. The operator of your TAS for VMs deployment can provide the vCPUs/memory ratio of the Diego Cell to developers.
If a Diego Cell is not already working at capacity, or if other workloads on the Diego Cell are idle, the Diego Cell can allocate more than the minimum amount of CPU time to an app instance.		 float64
absolute_usage The CPU time that an app instance has used, in nanoseconds.

absolute_usage / absolute_entitlement calculates a percentage of app instance usage per entitlement.		 float64

The way that Diego emits container metrics differs depending on the version of Loggregator used in your TAS for VMs deployment:

  • Loggregator v1: Diego emits most container metrics in a ContainerMetric envelope. Diego emits the cpu_entitlement, container_age, log_rate, and log_rate_limit container metrics in ValueMetric envelopes.

  • Loggregator v2: Diego emits all container metrics in gauge and counter envelopes. Diego emits the cpu_entitlement, container_age, log_rate, and log_rate_limit container metrics in separate gauge envelopes from other container metrics. The container metrics come in five envelopes:

    • One envelope containing cpu, disk, disk_quota, memory, and memory_quota
    • One envelope containing cpu_entitlement, and container_age
    • One envelope containing log_rate and log_rate_limit
    • One envelope containing rx_bytes
    • One envelope containing tx_bytes

Retrieving container metrics from the cf CLI

You can retrieve container metrics using the Cloud Foundry Command Line Interface (cf CLI).

Retrieving CPU, Memory, and Disk metrics

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

  1. In a terminal window, run:

    cf app APP-NAME

    Where APP-NAME is the name of the app.
    This command returns CPU, memory, and disk metrics for all instances of the app, similar to the following example:

    Showing health and status for app dora-example in org o / space s as admin...
    Label in output Metrics listed
    cpu CpuPercentage
    memory MemoryBytes of MemoryBytesQuota
    disk DiskBytes of DiskBytesQuota

The listed metrics are described in Diego container metrics.

  type:           web
  sidecars:
  instances:      1/1
  memory usage:   1024M
        state     since                  cpu    memory        disk          logging            details
  #0   running   2022-09-16T01:38:46Z   0.2%   36.3M of 1G   90.3M of 1G   0/s of unlimited

The preceding command shows what percentage of CPU the app is currently using relative to the total CPU on the host machine.

Retrieve network traffic metrics

To retrieve received- and transmitted bytes for all instances of an app:

  1. Install the Log Cache CLI Plug-in from the Log Cache cf CLI Plugin repository on GitHub.

  2. In a terminal window, run:

    cf tail --name-filter="bytes" APP-NAME

    Where APP-NAME is the name of the app.
    This command returns rx_bytes and tx_bytes metrics for all instances of the app, similar to the following example:

    2023-08-10T13:27:50.27+0000 [my-app/0] COUNTER rx_bytes:24842
2023-08-10T13:27:50.27+0000 [my-app/0] COUNTER tx_bytes:24306
2023-08-10T13:27:50.27+0000 [my-app/1] COUNTER rx_bytes:14832
2023-08-10T13:27:50.27+0000 [my-app/1] COUNTER tx_bytes:32312
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