Observe the application @ SAP Cloud Platform Cloud Foundry Environment

Estimated time

🕓 10 minutes

Objective

In this exercise you'll learn how you can get more info for the applications and services running in your trial account in the Cloud Foundry Environment, how you can get basic monitoring metrics and logs.

For all these exercises you have the information accessible via both tools: CF CLI and Cockpit. You will find below the commands that you should execute in CF CLI to get the info and the respective navigation in cockpit menus for the same.

Exercise description

List applications

List all applications in the target space with basic information for them.

CF CLI

cf apps

Cockpit

Navigate to your trial space that was created as part of Start Cloud Foundry Trial and click on Applications in the left-hand navigation menu.

List Services

List the created service instances and bindings in a target space

CF CLI

cf services

Cockpit

In the left-hand navigation you have the services menu and if you select the Service Instances you will see all instances created in your space and basic info about them.

Logs

Show logs for an application

CF CLI

• Tail logs for an app cf logs APP_NAME

cf logs product-list

💡 Note: Request the application in case you don't see any logs with the first command that tails logs.

💡 Note: To exit logs real-time stream mode in console click Ctrl + C

• Show recent logs for the application with cf logs APP_NAME

cf logs product-list --recent

Cockpit

To view application logs in Cockpit you navigate again to the list of applications in your space and select the application you pushed and is now started (click on the application name). Then in the left-hand navigation click on Logs and you will see a table displaying the recent application logs. In case your application has more than one application instance running you can select with a drop-down for which instance you want to see logs.

Metrics

Display health and status for an application including information for CPU, memory and disk usage.

CF CLI

In the console you can use the command cf app APP_NAME to see metrics for the application:

cf app product-list

Cockpit

If you are already in the concrete application view in the left-hand navigation select Overview and this is where you see similar information for your running application.

Events

Show recent application events (e.g. create, re-stage, update, etc.), when they happened and who triggered them.

CF CLI

cf events APP_NAME

Cockpit

Show events in Cockpit - in the dedicated application view, select in the left-hand navigation Events.

Environment Variables

Accessing Environment Variables

To list the environment variables, one can either use the CF CLI command cf env APP_NAME:

cf env product-list

or the Cockpit by going to the dedicated application view and selecting from the left-hand navigation Environment Variables.

The following examples show how to access environment variables from an application programatically: Java, NodeJS and Ruby samples.

System.getenv("VCAP_SERVICES");

process.env.VCAP_SERVICES

ENV['VCAP_SERVICES']

Set Environment Variables

Application specific environment variables can be set by the application developer either using the CF CLI:

cf set-env APP_NAME VARIABLE_NAME VARIABLE_VALUE

or by writing them directly into the manifest:

---
  ...
  env:
    VARIABLE_NAME_1: VARIABLE_VALUE_1
    VARIABLE_NAME_2: VARIABLE_VALUE_2

or using cockpit:

System Environment Variables

These are environment variables that Cloud Foundry makes available to your application container. The full list is:

• CF_INSTANCE_ADDR
• CF_INSTANCE_GUID
• CF_INSTANCE_INDEX
• CF_INSTANCE_IP
• CF_INSTANCE_INTERNAL_IP
• CF_INSTANCE_PORT
• CF_INSTANCE_PORTS
• HOME
• MEMORY_LIMIT
• PORT
• PWD
• TMPDIR
• USER
• VCAP_APP_HOST
• VCAP_APP_PORT
• VCAP_APPLICATION
• VCAP_SERVICES

The last one (VCAP_SERVICES) is important if your application is using bindable services because Cloud Foundry adds connection details to it when you restage your application after a service has been bound to it.

Health Checks

An application health check is a monitoring process that continually checks the status of a running Cloud Foundry app. In Cloud Foundry, the default timeout is 60 seconds and the maximum configurable timeout is 180 seconds. There are three types of health checks available in Cloud Foundry:

• http: the http health check performs a GET request to the configured http endpoint. When the health check receives an HTTP 200 response, the app is declared healthy. The configured endpoint must respond within 1 second to be considered healthy.

• port: this is the default check if nothing is specified. It makes a TCP connection to the port or ports configured for the app (default 8080). The TCP connection must be established within 1 second to be considered healthy.

• process: Diego ensures that any process declared for the app stays running. If the process exits, Diego stops and deletes the app instance. The health check can be specified either when pushing:

  cf push APP_NAME -u HEALTH-CHECK-TYPE -t HEALTH-CHECK-TIMEOUT
  

  or directly inside the manifest:

  ---
    ...
    health-check-type: http
    health-check-http-endpoint: /health
    timeout: 120
  

CF CLI

Usage:

cf set-health-check APP_NAME (process | port | http [--endpoint PATH])

Examples:

cf set-health-check APP_NAME http --endpoint PATH (default to /)
cf set-health-check APP_NAME port
cf set-health-check APP_NAME PROCESS_NAME

Show health check type for a given app with CF CLI command cf get-health-check APP_NAME. You can check what's the default health check configured for the Product List application:

cf get-health-check product-list