The term “workflow engine” is not clearly defined in software development and therefore we would like to give a brief overview of different aspects and types of workflow engines in the following blog post.
If you take a look at the Github page awesome-workflow-engines, you will find an impressive number of open source workflow engines. But not all of these engines solve the same problem. The idea behind the term ‘workflow’ can be very different and so the functionality of a workflow engine. In general a workflow is a series of tasks or activities that are required to complete a specific process. Such a process can involve multiple people, teams, microservices or even other IT systems. Thus, it becomes clear that when comparing Workflow Engines, various aspects must be taken into account.
When you hear about Kubernetes for the first time these days, you might get the impression that Kubernetes has a lot to do with AWS or Azure. If you read blogs or tutorials about Kubernetes or even if you join conferences, AWS and Azure is everywhere. It seems like a stupid idea not to believe that Kubernetes is based on these Internet platforms and can exist outside them.
But Kubernetes is far away from being a product or internet service that is only offered by Amazon or Microsoft. Rather, Kubernetes is an open source platform which is supported and developed by the Linux Foundation. Many people are working on the concepts for this open platform on a daily basis. And the goal of Kubernetes is to provide an open and powerful platform for operating container-based applications and Microservices.
It was never a walk in the park to setup and operate a stable and highly available cloud environment consisting of many servers. With Kubernetes companies and organizations should be enabled to run a server infrastructure for container-based applications by there own. Google has published his own experiences in this area and handed it over to the Linux Foundation in order to share that knowledge with others. And it was never the goal to make a product or put organizations in a dependent situation. On the other hand, it is a big business for companies like Microsoft and Amazon to offer their services based on the concepts of Kubernetes. Binding customers to their platforms is the new way of licencing. And they do a lot of marketing to succeed.
Build Your Own Cluster
Believe it or not, you can set up your own Kubernetes cluster and run it successfully in just a few hours. The concepts of Kubernetes provide many solutions for the problems that normally arise when operating large server environments. The result will be a stable and sustainable cloud infrastructure that you can control yourself.
Of course, Kubernetes is a complex system of many different building blocks. It takes time to get used to it. But today there are also a lot of concepts available to achieve success quickly. So don’t hesitate and take control of your personal cloud platform.
If you like, you can take a look at our open source project ‘Imixs-Cloud‘, which shows a simple and stable approach for the operation of a Kubernetes cluster.
The real-time processing of a continuous stream of business data and events is becoming increasingly important in modern IT architectures. This type of architecture, in which events are building the centre of data processing, is also known as a Reactive Streaming Architecture. In the following we will show how to solve some of the related challenges with the help of a workflow technology.
Let’s take a closer look at this type of architecture first. Basically, the event-based processing of data is not new and has actually been developed for decades in various specialized domains such as the financial sector. But since the last few years, new standards for processing data streams have emerged. Technologies like Apache Kafka, Storm, Flink or Spark are gaining popularity and pushing a new hype.
From industrial production systems to multiplayer computer games, so-called Streaming Architectures are used more and more frequently in order to be able to process big data in real time. Streaming architectures have developed into a central architectural element of modern technology companies. In many companies real-time streams have become the core system in their architecture.
The goal is to be able to integrate new system solutions more quickly and to connect any kind of data streams. The streaming architecture is not only found at technology giants such as Ebay, Netflix or Amazon, but today in every modern technology company that is working on the digitization of its business processes. So what are the main challenges in building such an architecture?
For most self managed Kubernetes environments the SQL database is one of the most important infrastructure parts. Typically SQL database servers are not designed to run on distributed nodes in an environment like Kubernetes. One solution is to run a single SQL database in a Kubernetes POD with a distributed filesystem like Longhorn or Ceph. This works well for example with PostgreSQL in most situations. Of course this can have some performance impacts and requires fast SSDs. Another solution is to run a distributed SQL Database like Cockroach. With the latest version of the Imixs-Cloud project we now offer a smart solution to run a SQL Database cluster within a self managed Kubernetes cluster.
Note: CockroachDB does not support the isolation level of transactions required for complex business logic. For that reason the Imixs-Workflow project does NOT recommend the usage of CockroachDB. See also the discussion here.
CockroachDB is a distributed SQL database with a build in replication mechanism. This means that the data is replicated over several nodes in a database cluster. This increases the scalability and resilience in the case that a single node fails. With its Automated-Repair feature the database also detects data inconsistency and automatically fixes faulty data on disks. The project is Open Source and hosted on Github.
CockroachDB supports a lower level of ACID transactions. This means guaranteed atomicity, isolation, consistency, and durability of data is not the same quality as in a PostgreSQL database . However CockroachDB can be used in combination with Jakarta EE and JPA. Supporting the PostgreSQL wire protocol, CockroachDB can be used with the standard PostgresSQL JDBC driver.
In this blog I will explain how to setup and customize Wildfly to run your Jakarta EE application on Kubernetes. We use this setup in our own Open Source project to run modern Jakarata EE applications on Kubernetes. You can find this project on Github.
Wildfly is Jakarta EE 8 compatible and includes the latest Eclipse MicroProfile in version 3.3. It provides a modern application framework out of the box to simplify the development of web applications and microservices. All runtime services minimize the heap allocation and applications are starting very fast with a minimum of memory.
With the new release v5.2.0, the open source workflow engine Imixs-Workflow now supports the asynchronous execution of BPMN events.
This feature is a big step forward especially in a microservice architecture. The new so called AsyncEvents make it much more easier to decouple a Rest API call from the processing life cycle of the workflow engine. In this way the request-response pattern shows better performance and allows a very clear design of complex business processes.
The AsyncEvents were already part of the Imixs-Microservice project in a pre-release and become now a core feature of the Imixs-Workflow engine. Especially in more complex architectures, the use of the so-called SAGA Pattern is an important building block. With asynchronous events Imixs-Workflow is now supporting this design pattern as a core feature. Read also our blog about building powerful microservice solutions with the SAGA Pattern.
In my last blog I explained the core concepts behind the Microservice Saga Pattern. In this blog I will address the problem from a more practical perspective by demonstrating how Imixs-Workflow can be used as a Saga Orchestrator within a Microservice architecture. First, I would like to give a brief review of the main concepts of the saga pattern. Later I show some implementation examples.
Everyone is talking about cloud technologies and of course every modern project relies on a microservice architecture. A variety of technologies and methods contribute to the success of this architecture pattern. But what does cloud native actually mean for the business world? How do companies and organizations implement business processes successfully beyond the big technology promises?
The basic idea of a microservice architecture is to break down the technical requirements of a software system into the smallest possible and therefore manageable services. The advantage: services created in this way can be developed independently of each other with different technologies by different teams. At the same time, we see new methods and technologies to connect, monitor and scale these services.
But just looking at the technology does’t mean that software can be developed faster and better. I would therefore like to compare some of these methods and technologies from the microservice architecture with the requirements for the development of business applications.
Microservices become the new disruptive technology for software development in it’s traditional way. It is the architectural style which brings up a new way to build software systems. The Microservice Architecture evolves very fast and in deed has a lot of success.
But there are also some disadvantages in Microservices. One of the critical parts is the rising complexity within a microservice architecture. It is a problem which is often overlooked in the beginning when all this euphoria lies within a greenfield project. And the problem is often denied for a long time by its advocates. But why does this happen?
The ‘Business Process Model And Notation’ standard is a well designed notation for describing business workflows. BPMN 2.0 becomes the standard for modeling business logic and fits very well the model driven software design in agile software projects.
The BPMN language, which is based on XML, was intended for users at all levels, from the business analysts who create the initial design, to the developers who implement the technical details, and finally, to the business users responsible for managing and monitoring the processes. BPMN 2.0 has evolved to become a complete specification trying to fit the needs to all people involved in the design of a business process. But writing BPMN in XML and visualizing business processes becomes nearly impossible without the use of a graphical tool.