diff --git a/content/en/blog/_posts/2019-08-28-cloud-native-java-controller-sdk.md b/content/en/blog/_posts/2019-11-26-cloud-native-java-controller-sdk.md similarity index 89% rename from content/en/blog/_posts/2019-08-28-cloud-native-java-controller-sdk.md rename to content/en/blog/_posts/2019-11-26-cloud-native-java-controller-sdk.md index 831a2bd349106..2474d07a95052 100644 --- a/content/en/blog/_posts/2019-08-28-cloud-native-java-controller-sdk.md +++ b/content/en/blog/_posts/2019-11-26-cloud-native-java-controller-sdk.md @@ -2,31 +2,31 @@ --- layout: blog title: "Develop a Kubernetes controller in Java" -date: 2019-08-28 +date: 2019-11-26 slug: Develop-A-Kubernetes-Controller-in-Java --- **Authors:** Min Kim (Ant Financial), Tony Ado (Ant Financial) -The official [Kubernetes Java SDK](https://github.com/kubernetes-client/java) project -recently released their latest work on providing the Java Kubernetes developers -a handy Kubernetes controller-builder SDK which is helpful for easily developing +The official [Kubernetes Java SDK](https://github.com/kubernetes-client/java) project +recently released their latest work on providing the Java Kubernetes developers +a handy Kubernetes controller-builder SDK which is helpful for easily developing advanced workloads or systems. ## Overall Java is no doubt one of the most popular programming languages in the world but -it's been difficult for a period time for those non-Golang developers to build up +it's been difficult for a period time for those non-Golang developers to build up their customized controller/operator due to the lack of library resources in the -community. In the world of Golang, there're already some excellent controller +community. In the world of Golang, there're already some excellent controller frameworks, for example, [controller runtime](https://github.com/kubernetes-sigs/controller-runtime), [operator SDK](https://github.com/operator-framework/operator-sdk). These -existing Golang frameworks are relying on the various utilities from the -[Kubernetes Golang SDK](https://github.com/kubernetes/client-go) proven to -be stable over years. Driven by the emerging need of further integration into -the platform of Kubernetes, we not only ported many essential toolings from the Golang -SDK into the kubernetes Java SDK including informers, work-queues, leader-elections, -etc. but also developed a controller-builder SDK which wires up everything into +existing Golang frameworks are relying on the various utilities from the +[Kubernetes Golang SDK](https://github.com/kubernetes/client-go) proven to +be stable over years. Driven by the emerging need of further integration into +the platform of Kubernetes, we not only ported many essential toolings from the Golang +SDK into the kubernetes Java SDK including informers, work-queues, leader-elections, +etc. but also developed a controller-builder SDK which wires up everything into a runnable controller without hiccups. @@ -34,19 +34,19 @@ a runnable controller without hiccups. Why use Java to implement Kubernetes tooling? You might pick Java for: -- __Integrating legacy enterprise Java systems__: Many companies have their legacy -systems or frameworks written in Java in favor of stability. We are not able to +- __Integrating legacy enterprise Java systems__: Many companies have their legacy +systems or frameworks written in Java in favor of stability. We are not able to move everything to Golang easily. -- __More open-source community resources__: Java is mature and has accumulated abundant open-source -libraries over decades, even though Golang is getting more and more fancy and -popular for developers. Additionally, nowadays developers are able to develop +- __More open-source community resources__: Java is mature and has accumulated abundant open-source +libraries over decades, even though Golang is getting more and more fancy and +popular for developers. Additionally, nowadays developers are able to develop their aggregated-apiservers over SQL-storage and Java has way better support on SQLs. ## How to use? -Take maven project as example, adding the following dependencies into your dependencies: +Take maven project as example, adding the following dependencies into your dependencies: ```xml @@ -56,8 +56,8 @@ Take maven project as example, adding the following dependencies into your depen ``` -Then we can make use of the provided builder libraries to write your own controller. -For example, the following one is a simple controller prints out node information +Then we can make use of the provided builder libraries to write your own controller. +For example, the following one is a simple controller prints out node information on watch notification, see complete example [here](https://github.com/kubernetes-client/java/blob/master/examples/src/main/java/io/kubernetes/client/examples/ControllerExample.java): ```java @@ -81,14 +81,14 @@ on watch notification, see complete example [here](https://github.com/kubernetes .build(); ``` -If you notice, the new Java controller framework learnt a lot from the design of +If you notice, the new Java controller framework learnt a lot from the design of [controller-runtime](https://github.com/kubernetes-sigs/controller-runtime) which -successfully encapsulates the complex components inside controller into several -clean interfaces. With the help of Java Generics, we even move on a bit and simply +successfully encapsulates the complex components inside controller into several +clean interfaces. With the help of Java Generics, we even move on a bit and simply the encapsulation in a better way. -As for more advanced usage, we can wrap multiple controllers into a controller-manager -or a leader-electing controller which helps deploying in HA setup. In a word, we can +As for more advanced usage, we can wrap multiple controllers into a controller-manager +or a leader-electing controller which helps deploying in HA setup. In a word, we can basically find most of the equivalence implementations here from Golang SDK and more advanced features are under active development by us. @@ -96,7 +96,6 @@ more advanced features are under active development by us. The community behind the official Kubernetes Java SDK project will be focusing on providing more useful utilities for developers who hope to program cloud native -Java applications to extend Kubernetes. If you are interested in more details, +Java applications to extend Kubernetes. If you are interested in more details, please look at our repo [kubernetes-client/java](https://github.com/kubernetes-client/java). Feel free to share also your feedback with us, through Issues or [Slack](http://kubernetes.slack.com/messages/kubernetes-client/). -