Lerna is a software stack for building high-availability, high-throughput systems.

  • By executing Lerna’s scripts to VMs running on the cloud (public or private), you can build an environment that is configured to achieve high availability and high throughput.
  • In that environment, designing and implementing applications based on the actor model (Akka) and CQRS(Command Query Responsibility Segregation) with Event Sourcing architecture allows you to build highly available systems.
  • Libraries and reference implementations for design and implementation are provided.


High availability and high throughput

  • Eliminates the bottleneck of writing to the RDBMS by applying the CQRS with Event Sourcing architecture to the application layer
  • High Availability and Scalability with Akka Cluster
  • Provides responsiveness by making the application stateful, while providing fast failover with guaranteed consistency using Raft

  • Benchmark test report of Lerna available here

Platform independent

  • Fast failover at the middleware and application layers with platform independence, based on the premise that the server (VM) will stop.
  • This ensures high availability independent of hardware and specific cloud environments

Low cost and fast delivery

  • No need to purchase expensive high-availability servers; high availability can be achieved at low cost by using OSS middleware.
  • Because it can be built on the cloud, it reduces the lead time for hardware procurement and improves delivery speed.


Name Description
application template a template for creating a new project
Terraform scripts scripts to build the environment
learning content hands-on content learning Akka and Scala with Lerna
system design documents documentation for developing with Lerna
application libraries libraries for developing applications that run on Lerna Stack ( API Doc )
sample application a sample application for developing with Lerna application libraries
HA library Akka extension for fast recovery from failure with replicating stateful entity on multiple nodes in Cluster. ( API Doc )
benchmark report for Lerna a benchmark report measuring availability and throughput of Lerna
sample application for HA library (Minimum) a sample application for developing with HA library
sample application for HA library (Bank Account) a sample application that manages bank account balances for developing with HA library
batch parallelization library a library for parallelizing batch processing with Nablarch Batch Framework
sample application for batch library a sample application for developing with batch parallelization library
benchmark report for batch library a report testing speed improvement effect by parallelizing processing using batch parallelization library

Getting started



Reactive systems that focus on availability from TIS Inc.



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