Camel Rebirth with Subsecond Experiences

This post was originally published here. Check out my new Kubernetes Patterns book and  follow me @bibryam for future blog posts.

A look at the past decade

The integration space is in constant change. There are many open source projects and closed source technologies that have not passed the test of time and disappeared from the middleware stacks for good. After a decade, Apache Camel is still here and becoming even stronger for the next decade of integration.

Gang of Four for integration

Apache Camel started life as an implementation of the Enterprise Integration Patterns (EIP) book. Today, these patterns are the equivalent of the object-oriented Gang of Four Design Patterns but for messaging and integration domain. They are agnostic of programing language, platform, architecture, and provide a universal language, notation and description of the forces around fundamental messaging primitives.

But Camel community did not stop with these patterns, and kept evolving and adding newer patterns from SOA, Microservices, Cloud Native and Serverless paradigms. As a result, Camel turned into a generic pattern based integration framework suitable for multiple architectures.

Universal library consumption model

While the patterns gave the initial spark to Camel, its endpoints quickly became popular and turned into a universal protocol for using Java based integration libraries as connectors. Today, there are hundreds of Java libraries that can be used as Camel connectors using the Camel endpoint notation. It takes a while to realize that Camel can also be used without the EIPs and the routing engine. It can act as a connector framework where all libraries are consumed as universal URIs without a need for understanding the library specific factories and configurations that vary widely across Java libraries.

The right level of abstraction

When you talk to developers who have not used Camel in anger before, they will tell you that it is possible to do integration without Camel. And they are right about the 80% of the easy use cases, but not for the remaining 20% of the cases that can turn a project into a multi-year frustrating experience. What they do not realize yet is that without Camel, there are multiple manual ways of doing the same thing, but none are validated by the experience of hundreds of open source developers. And if you fast-forward a few years, 10s of different systems to integrate with, and 10s of developers coming and going, 100s of microservices, an integration project can quickly turn into a bespoke home-grown framework that nobody wants to work on. Doing integration is easy, but doing good integration that will evolve and grow for many years, by many teams, is the hardest part. Camel addresses this challenge with universal patterns and connectors, combined with integration focused DSLs, that have passed the test of time. Next time, if you think you don't need Camel, your are either thinking for short term gains, or you are not realizing yet how complex integration can become.

Embracing change

It takes only a couple of painful experiences in large integration projects to start appreciating Camel. But Camel is not great only because it was started by and built on the works of great minds, it is great because it evolves thanks to the world's knowledge, shared through the open source model and its networking effects. Camel started as the routing layer in ESBs during SOA period with a lot of focus on XML, WS, JBI, OSGI etc, but then it quickly adapted for REST, Swagger, Circuit breakers, SAGAs, and Spring Boot in the Microservices era. And the world has not stopped there, with Docker and Kubernetes, and now Serverless architecture, Camel keeps embracing the change. That is because Camel is written for integrating changing environments, and Camel itself grows and shines on change. Camel is a change enabling library for integration.

Behind the scene engine

One of the Camel secret sauces is that it is a non-intrusive, unopinionated, small (5MB and getting smaller) integration library without any affinity where and how you consume it. If you notice, this is the opposite of an ESB as commonly Camel is confused with because of its extensive capabilities. Over the years, Camel has been used as the internal engine powering projects such as:
  • Apache ServiceMix ESB
  • Apache ActiveMQ
  • Talend ESB
  • JBoss Switchyard
  • JBoss Fuse Service Works
  • Red Hat Fuse
  • Fuse Online/Syndesis 
  • And many other frameworks mentioned here.
You can use Camel standalone, embed it with Apache Tomcat, with Spring Boot starters, JBoss WildFly, Apache Karaf, Vert.x, Quarkus, you name it. Camel doesn't care and it will bring superpowers to your project every time.

Looking to the future

Nobody can tell how the ideal integration stack will look like in a decade, nor can I. But I will tell you about two novelties coming into Apache Camel now (and to Red Hat Fuse later), and why they will have a noticeable positive effect for the developers and the business. I call these changes as subsecond deployment and subsecond startup of Camel applications.

Subsecond deployments to Kubernetes

There was a time when cloud-native meant different technologies. Today, after a few years of natural selection and consolidation in the industry, cloud-native means applications created specifically for Kubernetes and its ecosystem of projects around CNCF. Even with this definition, there are many shades of cloud-native, from running a monolithic non-scalable application in a container, to triggering a function that is fully embracing the cloud-native development and management practices. The Camel community has realized that Kubernetes is the next generation application runtime, and it is steadily working on making Camel a Kubernetes native integration engine. The same way Camel is a first-class citizen in OSGI containers, JEE application servers, other fat-jar runtimes, Camel is becoming a first-class citizen on Kubernetes, integrating deeply and benefiting from the resiliency and scalability offered by the platform.

Here are a few of the many enhancement efforts going on in this direction:
  • Deeper Kubernetes integration - Kubernetes API connector, full health-check API implementation for Camel subsystems, service discovery through a new ServiceCall EIP, configuration management using ConfigMaps. Then a set of application patterns with special handling on Kubernetes such as: clustered singleton routes, scalable XA transactions (because sometimes, you have to), SAGA pattern implementation, etc.
  • Cloud-native integrations - support for other cloud-native projects such as exposing Camel metrics for Prometheus, tracing Camel routes through Jaeger, JSON formatted logging for log aggregation, etc.
  • Immutable runtimes - whether you use the minimalist immutable Karaf packaging, or Spring Boot, Camel is a first class citizen ready to put in a container image. There are also Spring Boot starter implementations for all Camel connectors, integration with routes, properties, converters, and whatnot.
  • Camel 3 - is a fact and actively progressing. A big theme for Camel 3 is to make it more modular, smaller, with faster startup time, reactive, non-blocking and triple awesome. This is the groundwork needed to restructure Camel for the future cloud workloads.
  • Knative integration - Knative is an effort started by Google in order to bring some order and standardization in the serverless world dominated by Amazon Lambda. And Camel is among the projects that integrate with Knative primitives from early days and enhances the Knative ecosystem with hundreds of connectors acting as generic event sources.  
  • And here is a real game-changer initiative: Camel-K (a.k.a deep Kubernetes integration for Camel) - we have seen that Camel is typically embedded into the latest modern runtime where it acts as the developer-friendly integration engine behind the scene. The same way Camel used to benefit from JEE services in the past for hot-deployment, configuration management, transaction management, etc, today Camel-K allows Camel runtime to benefit from Kubernetes features for high-availability, resiliency, self-healing, auto-scaling, and basically distributed application management in general. The way Camel-K achieves this is through a CLI and an Operator where the latter is able to understand the Camel applications, its build time dependencies, runtime needs, and make intelligent choices from the underlying Kubernetes platform and its additional capabilities (from Knative, Istio, Openshift and others in the future). It can automate everything on the cluster such as picking the best suited container image, runtime management model and update them when needed. The CLI can automate the tasks that are on the developer machine such as observing the code changes and streaming those to the Kubernetes cluster, and printing the logs from the running Pods. 
Camel route auto-deployment to Kubernetes with Camel-K
Camel-K operator understands two domains: Kubernetes and Camel. By combining knowledge of both areas, it can automate tasks that usually require a human operator.
The really powerful part is that, with Camel-K, a Camel route can be built and deployed from source code to a running Camel route on Kubernetes in less than a second!
Time to deploy and run a Camel integration(in seconds)
Forget about making a coffee, or even having a sip while building and deploying a Camel route with Camel K. As soon as you make changes to your source code and open a browser, the Camel route will be running in Kubernetes. This has a noticeable impact on the way the developers write Camel code, compile, drink coffee, deploy and test. Apart from changing the development practices and habits, this toolset will significantly reduce the development cycles which would be noticed by the business stakeholders too. For live demonstration, check out the following awesome video from Fuse engineers working on Camel-K project.

Subsecond startups of Camel applications

A typical enterprise integration landscape is composed of stateless services, stateful services, clustered applications, batch jobs, file transfers, messaging, real time integrations, and may be even blockchain based business processes. To that mix, today, we also have to add serverless workloads as well, which is best suited for event driven workloads. Historically, the heavy and slow Java runtime had significant drawbacks compared Go, Javascript and other light runtimes in the serverless space. That is one of the main motivations for Oracle to create GraalVM/Substrate VM. Substrate VM is a framework that enables ahead-of-time (AOT) compilation of Java applications into native executables that are light and fast. Then a recent effort by Red Hat led to the creation of Quarkus project which improves further the resource consumptions, startup and response times of Java applications mind-blowingly (a term not-used lightly here).

Supersonic Subatomic Java with Quarkus
As you can see from the metrics above, Quarkus combined with SubstrateVM is not a gradual evolution. It is a mutation, and a revolutionary jump that suddenly changes the perspectives on the Java’s footprint and speed in the cloud native workloads. It makes Java friendly for serverless architecture. Considering the huge Java ecosystem composed of developers and libraries, it even turns Java into the best suited language for Serverless applications. And Camel combined with Quarkus, the best placed integration library in this space.


With the explosion of Microservices architecture, the number of services has increased tenfold which gave birth to Kubernetes-enabled architectures. These architectures are highly dynamic in nature, and most powerful with light and fast runtimes that enable instant scale up and higher deployment density.

Camel is the framework to fill the space between disparate systems and services. It offers data consistency guarantees, reliable communication, failover, failure detection and recovery, and so on, in a way that makes developers productive. Now, imagine the same powerful Apache Camel based integration in 2020 that: deploys to Kubernetes in 20ms; starts up in 20ms; requires 20MB memory, consumes 20MB on the disk... That is regardless whether it runs as a stateless application in a container, or as a function on KNative. That is 100x faster deployments to Kubernetes, 100x faster startup time, 10x less resource consumption allowing real-time scale-up, scale-down, and scale to zero. That is a change that the developers will notice during development, users will notice when using the system, and the business will notice on the infrastructure cost and overall delivery velocity. That is the real cloud-native era we have been waiting for.


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