App runtime

The app runtime is the environment apps are executed in.

Environment variables

Environment variables are injected into the app at runtime by Kubernetes. Variables are added based on the following order, where later values override earlier ones with the same name:

1. Space (set by administrators)
2. App (set by developers)
3. System (set by Kf)

Kf provides the following system environment variables:

Service credentials from bound services get injected into Apps via the VCAP_SERVICES environment variable. The variable is a valid JSON object with the following structure.

VCAPServices

A JSON object where the keys are Service labels and the values are an array of VCAPService. The array represents every bound service with that label. User provided services are placed under the label user-provided.

Example

{
  "mysql": [...],
  "postgresql": [...],
  "user-provided": [...]
}

VCAPService

This type represents a single bound service instance.

Example

{
  "binding_name": string,
  "instance_name": string,
  "name": string,
  "label": string,
  "tags": string[],
  "plan": string,
  "credentials": object
}

Fields

VCAP_APPLICATION

TheVCAP_APPLICATION environment variable is a JSON object containing metadata about the App.

Example

{
  "application_id": "12345",
  "application_name": "my-app",
  "application_uris": ["my-app.example.com"],
  "limits": {
    "disk": 1024,
    "mem": 256
  },
  "name": "my-app",
  "process_id": "12345",
  "process_type": "web",
  "space_name": "my-ns",
  "uris": ["my-app.example.com"]
}

Fields

Missing Fields

Some fields in VCAP_APPLICATION that are in Cloud Foundry are currently not supported in Kf.

Besides CF-specific and deprecated fields (cf_api, host, users) the fields that are not supported in Kf are:

• application_version (identical to version)
• organization_id
• organization_name
• space_id
• start (identical to started_at)
• started_at_timestamp (identical to state_timestamp)