Configuration

This section explains Kronos configuration.

Scheduler Configuration

Scheduler configuration is defined in scheduler.yaml file and is picked by the Kronos from classpath to initialize and start the scheduler.

Store

A pluggable persistence store to maintain the state of the system.

A store is configured in the scheduler.yaml file under storeProviderConfig section and is used to store the state of Kronos. The user can also provide a custom implementation of store.

KEY	DESCRIPTION	TYPE	DEFAULT	MANDATORY
providerClass	fully qualified class name of the StoreProvider implementation	string	None	yes
config	additional configuration required by the store provider during instantiation	objectnode	None	no

storeServiceConfig:
  storeServiceClass: com.cognitree.kronos.scheduler.store.jdbc.StdJDBCStoreService
  config:
    connectionURL: jdbc:hsqldb:hsql://localhost/tmp/kronos
    driverClass: org.hsqldb.jdbcDriver
    username: kronos
    password: kronos123

In the above sample, a standard jdbc store is configured.

Executor Configuration

Executor configuration is defined in executor.yaml file and is picked by the Kronos from classpath to initialize and start the executor.

Task Handler

For each type of task, a handler needs to be configured to execute the task. A handler is configured in the executor.yaml file under handlerConfig section. The user can also implement and configure a custom task handler to handle tasks.

KEY	DESCRIPTION	TYPE	DEFAULT	MANDATORY
handlerClass	fully qualified class name of the TaskHandler implementation	string	None	yes
config	additional configuration required by the handler during instantiation	objectnode	None	no
maxParallelTasks	max number of tasks allowed to be executed in parallel	string	max cores/2	no

# configure task handlers
taskHandlerConfig:
  # type of task to be handled by the handler
  shellCommand:
    # handler implementation used to handle the task of type shellCommand
    handlerClass: com.cognitree.kronos.executor.handlers.ShellCommandHandler
    # max parallel tasks handler is allowed to execute at any point in time
    maxParallelTasks: 4

In the above sample, Shell Command Handler is configured to handle tasks of type shellCommand.

Queue Configuration

The queue is used by the scheduler and executor to exchange messages. A producer and a consumer for the queue is to be configured in queue.yaml. The user can provide a custom implementation of queue.

Producer Configuration

A producer for the queue is configured in the queue.yaml file under producerConfig section.

KEY	DESCRIPTION	TYPE	DEFAULT	MANDATORY
producerClass	fully qualified class name of the Producer implementation	string	None	yes
config	additional configuration required by the producer during instantiation	objectnode	None	no

Consumer Configuration

A producer for the queue is configured in the queue.yaml file under consumerConfig section.

KEY	DESCRIPTION	TYPE	DEFAULT	MANDATORY
consumerClass	fully qualified class name of the Consumer implementation	string	None	yes
pollIntervalInMs	time duration between successive poll to queue in millisecond	long	1000	no
config	additional configuration required by the consumer during instantiation	objectnode	None	no

# configure producer and consumer for the queue
producerConfig:
  producerClass: com.cognitree.kronos.queue.producer.InMemoryProducer
consumerConfig:
  consumerClass: com.cognitree.kronos.queue.consumer.InMemoryConsumer
  pollIntervalInMs: 100
# topic to use to publish task status reported by executor and consumed by scheduler
taskStatusQueue: taskstatus

In the above sample, an in-memory queue is configured.