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Version: 1.18

Flink engine

Architecture overview​

Nussknacker scenarios can be deployed on Apache Flink.

Following diagrams illustrate architecture of Nussknacker setup with Flink compared to standard Flink application deployment (more details about architecture of Flink itself can be found here):

Lite with request-response layers diagramLite with streaming layers diagram
Flink without NuFlink with Nu

This architecture assumes that:

  • Flink should be deployed in Session Mode
  • Scenario runtimes (within one scenario type) are executed on the same Flink cluster
  • which means, that all scenario deployments (within one scenario type) use the same resources - unstable behavior of one job can have impact on others

Scenario deployment​

To deploy scenario to Flink cluster Nussknacker prepares JAR file with Model code and serialized scenario representation. This package is then sent via REST API to Flink JobManager which takes the initiative and spawns a job on one or more Flink Task Managers.

Scenario execution​

The resulting job uses standard Flink API/Components, e.g. Kafka sources/sinks, operators which can be stateful, checkpoints mechanisms to make processing fault-tolerant, etc.