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 storeServiceConfig 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
storeServiceClass	fully qualified class name of the StoreService 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.

Email Notifications

Kronos can be configured to send email notifications to a number of recepients if a job is successful or failed. A email service is configured in the scheduler.yaml file under mailConfig section and is used to send the email notifications.

KEY	DESCRIPTION	TYPE	DEFAULT	MANDATORY
smtpHost	smtp server host	string	None	yes
port	smtp server port	int	None	yes
userEmail	email address to use to send email	string	None	yes
password	password to use for the above email address	string	None	yes
fromName	name to set as from while sending email	string	None	yes
fromEmail	email to set as frome while sending email	string	None	yes
replyTo	set the reply to address while sending email	string	fromEmail	no

Note: Recepient for email notification is configured at a workflow level. Check creating workflow guide for more details.

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
config	additional configuration required by the consumer during instantiation	objectnode	None	no

Topic Configuration

Kronos uses a set of topic for its internal communication between scheduler and the executor. These topic are configured in the queue.yaml file.

| KEY | DESCRIPTION | TYPE | DEFAULT | MANDATORY | | taskStatusQueue | topic name to use to exchange task status updates | string | None | yes | | controlMessageQueue | topic name to use to exchange control messages | string | None | yes | | pollIntervalInMs | time duration between successive poll to queue in millisecond | long | None | yes |

# configure producer and consumer for the queue
producerConfig:
  producerClass: com.cognitree.kronos.queue.producer.InMemoryProducer
consumerConfig:
  consumerClass: com.cognitree.kronos.queue.consumer.InMemoryConsumer
taskStatusQueue: taskstatus
controlMessageQueue: controlmessages
pollIntervalInMs: 5000

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