Training Application

This application is used in the cloud-native training catalogue. The images can be found in quay.

The aim of this application is to be used in the context of trainings for Docker, Kubernetes, Istio, Helm, ...

Functionality of the application

Nothing, besides possibly (depending on the application configuration) showing a cute cat image 🙀.

Available Endpoints

NOTE: The application offers the following endpoints on port 8080

/

Root endpoint, the output depends on the application configuration.

Eg the response could be delayed for a configurable amount of seconds.

/liveness

Endpoint of the application to signal if the application is in a healthy state.

If everything is fine the application will respond with a 200 status code, if not the application should respond with a 500 status code.

/readiness

Endpoint of the application to signal if the application is ready to receive requests.

If everything is fine the application will respond with a 200 status code, if not the application should respond with a 503 status code.

Available Commands

NOTE: The application offers the following commands via stdin

Command	Description
help	Get info about available commands and endpoints
init	Re-initialize the application
config	Print out the current application configuration
set ready	Application readiness probe will be successful
set unready	Application readiness probe will fail
set alive	Application liveness probe will be successful
set dead	Application liveness probe will fail
leak mem	Leak memory
leak cpu	Leak CPU
request <url>	Request a URL, e.g., request https://www.kubermatic.com/
delay / <seconds>	Set delay for the root endpoint (/) in seconds, e.g., delay / 5
disable /	The root endpoint (/) will respond with a 503 status code
enable /	The root endpoint (/) will respond with a 200 status code

INSIDE A CONTAINER If you want to send commands to the application you have to use of docker attach my-training-application-container. The container als has to have tty enabled.

INSIDE A POD If you want to send commands to the application you have have to use of kubectl attach -it training-application-pod and have the following flags set in the pod manifest:

apiVersion: v1
kind: Pod
metadata:
  name: training-application
spec:
  containers:
    - name: training-application
      image: quay.io/kubermatic-labs/training-application:3.0.0
      imagePullPolicy: Always
      tty: true # <= add this flag
      stdin: true # <= add this flag
      ports:
        - name: http
          containerPort: 8080

Configuring the application

configFilePath

• Description: Path to the config file
• Type: string
• Default Value: "./training-application.conf"
• Usage: application arg, you can set this via eg ./training-application --configFilePath my.conf

port

• Description: Port on which the application provides its services
• Type: int
• Default Value: 8080
• Usage: via config file

alive

• Description: Flag to indicate the applications liveness
• Type: bool
• Default Value: true
• Usage: configurable via the commands set alive and set dead

ready

• Description: Flag to indicate the applications readiness
• Type: bool
• Default Value: false
• Usage: true after startUpDelaySeconds , false on graceful shutdown; configurable via the commands set ready and set unready

name

• Description: The name of the application
• Type: string
• Default Value: "not set"
• Usage: via config file or via the environment variable APP_NAME

version

• Description: The version of the application
• Type: string
• Default Value: "not set"
• Usage: via config file or via the environment variable APP_VERSION

message

• Description: A message to be shown on the root endpoint
• Type: string
• Default Value: "not set
• Usage: via config file or via the environment variable APP_MESSAGE

color

• Description: The background color of the root endpoint
• Type: string
• Default Value: "not set"
• Usage: via config file or via the environment variable APP_COLOR

rootEnabled

• Description: Flag to indicate if the root endpoint (/) is enabled or not
• Type: bool
• Default Value: true
• Usage: configurable via the commands enable / and disable /

rootDelaySeconds

• Description: For delaying requests to the root endpoint
• Type: int
• Default Value: 0
• Usage: via the command delay / <seconds>, eg "delay / 10"

startUpDelaySeconds

• Description: Time the application will take to start
• Type: int
• Default Value: 0
• Usage: via config file

tearDownDelaySeconds

• Description: Time the application will take to gracefully shut down
• Type: int
• Default Value: 0
• Usage: via config file

logToFileOnly

• Description: Log only to the file named training-application.log, if set to true no logging to stdout will happen
• Type: bool
• Default Value: false
• Usage: via config file

catMode

• Description: Flag to get cute cat images in the root endpoint
• Type: bool
• Default Value: false
• Usage: via config file

Building the application

make build

Running the application natively

make run

Building the Image

make docker-build

Running the Image

make docker-run