Skip to content

Commit 19362a9

Browse files
csviricsviri
authored
docs: /readme.md and docs update (#834)
1 parent bed8ebc commit 19362a9

File tree

4 files changed

+55
-292
lines changed

4 files changed

+55
-292
lines changed

‎README.md

Lines changed: 21 additions & 291 deletions
Original file line numberDiff line numberDiff line change
@@ -3,312 +3,42 @@
33
![Java CI with Maven](https://github.com/java-operator-sdk/java-operator-sdk/workflows/Java%20CI%20with%20Maven/badge.svg)
44
[![Discord](https://img.shields.io/discord/723455000604573736.svg?label=&logo=discord&logoColor=ffffff&color=7389D8&labelColor=6A7EC2)](https://discord.com/channels/723455000604573736)
55

6-
Build Kubernetes Operators in Java without hassle. Inspired
7-
by [operator-sdk](https://github.com/operator-framework/operator-sdk).
6+
#Build Kubernetes Operators in Java Without Hassle
87

9-
Our webpage with documentation is getting better every day: https://javaoperatorsdk.io/
8+
## Documentation
109

11-
**!! NOTE the main branch now contains source code for v2, which is under development, for actual
12-
version see [v1 branch](https://github.com/java-operator-sdk/java-operator-sdk/tree/v1) !!**
10+
Documentation can be found on the **[JOSDK WebSite](https://javaoperatorsdk.io/)**.
1311

14-
Table of Contents
15-
==========
12+
It's getting better every day! :)
1613

17-
1. [Features](#Features)
18-
1. [Why build your own Operator?](#Why-build-your-own-Operator)
19-
1. [Roadmap and Release Notes](#Roadmap-and-Release-Notes)
20-
1. [Join us on Discord!](#Join-us-on-Discord)
21-
1. [Usage](#Usage)
14+
## Contact us
2215

23-
## Features
16+
Join us on [Discord](https://discord.gg/DacEhAy) or feel free to ask any question on
17+
[Kubernetes Slack Operator Channel](https://kubernetes.slack.com/archives/CAW0GV7A5)
18+
19+
## How to Contribute
20+
21+
See the [contribution](https://javaoperatorsdk.io/docs/contributing) guide on the website.
22+
23+
## What is Java Operator SDK
24+
25+
Java Operator SDK is a higher level framework and related tooling to support writing Kubernetes Operators in Java.
26+
It makes it use to utilize best practices and patters of an Operator development. Features include:
2427

2528
* Framework for handling Kubernetes API events
2629
* Automatic registration of Custom Resource watches
2730
* Retry action on failure
2831
* Smart event scheduling (only handle the latest event for the same resource)
2932
* Handling Observed Generations automatically
30-
* for all see [features](https://javaoperatorsdk.io/docs/features) section on the webpage
31-
32-
Check out
33-
this [blog post](https://csviri.medium.com/deep-dive-building-a-kubernetes-operator-sdk-for-java-developers-5008218822cb)
34-
about the non-trivial yet common problems needed to be solved for every operator. In case you are interested how to
35-
handle more complex scenarios take a look
36-
on [event sources](https://csviri.medium.com/java-operator-sdk-introduction-to-event-sources-a1aab5af4b7b)
37-
.
38-
39-
## Why build your own Operator?
40-
41-
* Infrastructure automation using the power and flexibility of Java.
42-
See [blog post](https://blog.container-solutions.com/cloud-native-java-infrastructure-automation-with-kubernetes-operators)
43-
.
44-
* Provisioning of complex applications - avoiding Helm chart hell
45-
* Integration with Cloud services - e.g. Secret stores
46-
* Safer deployment of applications - only expose cluster to users by Custom Resources
47-
48-
#### Overview of the 1.9.0 changes
49-
50-
- The Spring Boot starters have been moved to their own repositories and are now found at:
51-
- https://github.com/java-operator-sdk/operator-framework-spring-boot-starter
52-
- https://github.com/java-operator-sdk/operator-framework-spring-boot-starter-test
53-
- Updated Fabric8 client to version 5.4.0
54-
- It is now possible to configure the controllers to not automatically add finalizers to resources. See the `Controller`
55-
annotation documentation for more details.
56-
- Added the possibility to configure how many seconds the SDK will wait before terminating reconciliation threads when a
57-
shut down is requested
58-
59-
#### Overview of the 1.8.0 changes
60-
61-
- The quarkus extension has been moved to the quarkiverse and is now found at
62-
https://github.com/quarkiverse/quarkus-operator-sdk
63-
64-
##### Overview of the 1.7.0 changes
65-
66-
- `Doneable` classes have been removed along with all the involved complexity
67-
- `Controller` annotation has been simplified: the `crdName` field has been removed as that value is computed from the
68-
associated custom resource implementation
69-
- Custom Resource implementation classes now need to be annotated with `Group` and `Version`
70-
annotations so that they can be identified properly. Optionally, they can also be annotated with
71-
`Kind` (if the name of the implementation class doesn't match the desired kind) and `Plural` if the plural version
72-
cannot be automatically computed (or the default computed version doesn't match your expectations).
73-
- The `CustomResource` class that needs to be extended is now parameterized with spec and status types, so you can have
74-
an empty default implementation that does what you'd expect. If you don't need a status, using `Void` for the
75-
associated type should work.
76-
- Custom Resources that are namespace-scoped need to implement the `Namespaced` interface so that the client can
77-
generate the proper URLs. This means, in particular, that `CustomResource`
78-
implementations that do **not** implement `Namespaced` are considered cluster-scoped. As a consequence,
79-
the `isClusterScoped` method/field has been removed from the appropriate classes (`Controller` annotation, in
80-
particular) as this is now inferred from the `CustomResource`
81-
type associated with your `Controller`.
82-
83-
Many of these changes might not be immediately apparent but will result in `404` errors when connecting to the cluster.
84-
Please check that the Custom Resource implementations are properly annotated and that the value corresponds to your CRD
85-
manifest. If the namespace appear to be missing in your request URL, don't forget that namespace-scoped Custom Resources
86-
need to implement the `Namescaped` interface.
87-
88-
## Join us on Discord!
89-
90-
[Discord Invite Link](https://discord.gg/DacEhAy)
91-
92-
## Usage
93-
94-
We have several simple Operators under the [smoke-test-samples](smoke-test-samples) directory:
95-
96-
* *pure-java*: Minimal Operator implementation which only parses the Custom Resource and prints to stdout. Implemented
97-
with and without Spring Boot support. The two samples share the common module.
98-
* *spring-boot-plain*: Sample showing integration with Spring Boot.
99-
100-
There are also more complete samples in the standalone [sample-operators](sample-operators):
101-
102-
* *webserver*: Simple example creating an NGINX webserver from a Custom Resource containing HTML code.
103-
* *mysql-schema*: Operator managing schemas in a MySQL database.
104-
* *tomcat*: Operator with two controllers, managing Tomcat instances and Webapps for these.
105-
106-
Add [dependency](https://search.maven.org/search?q=a:operator-framework) to your project with Maven:
107-
108-
```xml
109-
110-
<dependency>
111-
<groupId>io.javaoperatorsdk</groupId>
112-
<artifactId>operator-framework</artifactId>
113-
<version>{see https://search.maven.org/search?q=a:operator-framework for latest version}</version>
114-
</dependency>
115-
```
116-
117-
Or alternatively with Gradle, which also requires declaring the SDK as an annotation processor to generate the mappings
118-
between controllers and custom resource classes:
119-
120-
```groovy
121-
dependencies {
122-
implementation "io.javaoperatorsdk:operator-framework:${javaOperatorVersion}"
123-
annotationProcessor "io.javaoperatorsdk:operator-framework:${javaOperatorVersion}"
124-
}
125-
```
126-
127-
Once you've added the dependency, define a main method initializing the Operator and registering a controller.
128-
129-
```java
130-
public class Runner {
131-
132-
public static void main(String[] args) {
133-
Operator operator = new Operator(DefaultConfigurationService.instance());
134-
operator.register(new WebPageReconciler());
135-
operator.start();
136-
}
137-
}
138-
```
139-
140-
The Controller implements the business logic and describes all the classes needed to handle the CRD.
141-
142-
```java
143-
144-
@ControllerConfiguration
145-
public class WebPageReconciler implements Reconciler<WebPage> {
146-
147-
// Return the changed resource, so it gets updated. See javadoc for details.
148-
@Override
149-
public UpdateControl<WebPage> reconcile(WebPage resource,
150-
Context context) {
151-
// ... your logic ...
152-
return UpdateControl.updateStatus(resource);
153-
}
154-
}
155-
```
156-
157-
A sample custom resource POJO representation
158-
159-
```java
160-
161-
@Group("sample.javaoperatorsdk")
162-
@Version("v1")
163-
public class WebPage extends CustomResource<WebPageSpec, WebPageStatus> implements
164-
Namespaced {
165-
166-
}
167-
168-
public class WebPageSpec {
169-
170-
private String html;
171-
172-
public String getHtml() {
173-
return html;
174-
}
175-
176-
public void setHtml(String html) {
177-
this.html = html;
178-
}
179-
}
180-
```
181-
182-
### Deactivating CustomResource implementations validation
183-
184-
The operator will, by default, query the deployed CRDs to check that the `CustomResource`
185-
implementations match what is known to the cluster. This requires an additional query to the cluster and, sometimes,
186-
elevated privileges for the operator to be able to read the CRDs from the cluster. This validation is mostly meant to
187-
help users new to operator development get started and avoid common mistakes. Advanced users or production deployments
188-
might want to skip this step. This is done by setting the `CHECK_CRD_ENV_KEY` environment variable to `false`.
189-
190-
### Automatic generation of CRDs
191-
192-
To automatically generate CRD manifests from your annotated Custom Resource classes, you only need to add the following
193-
dependencies to your project:
194-
195-
```xml
196-
197-
<dependency>
198-
<groupId>io.fabric8</groupId>
199-
<artifactId>crd-generator-apt</artifactId>
200-
<scope>provided</scope>
201-
</dependency>
202-
```
203-
204-
The CRD will be generated in `target/classes/META-INF/fabric8` (or in `target/test-classes/META-INF/fabric8`, if you use
205-
the `test` scope) with the CRD name suffixed by the generated spec version. For example, a CR using
206-
the `java-operator-sdk.io` group with a `mycrs` plural form will result in 2 files:
207-
208-
- `mycrs.java-operator-sdk.io-v1.yml`
209-
- `mycrs.java-operator-sdk.io-v1beta1.yml`
210-
211-
**NOTE:**
212-
> Quarkus users using the `quarkus-operator-sdk` extension do not need to add any extra dependency to get their CRD generated as this is handled by the extension itself.
213-
214-
### Quarkus
215-
216-
A [Quarkus](https://quarkus.io) extension is also provided to ease the development of Quarkus-based operators.
217-
218-
Add [this dependency](https://search.maven.org/search?q=a:quarkus-operator-sdk)
219-
to your project:
220-
221-
```xml
222-
223-
<dependency>
224-
<groupId>io.quarkiverse.operatorsdk</groupId>
225-
<artifactId>quarkus-operator-sdk</artifactId>
226-
<version>{see https://search.maven.org/search?q=a:quarkus-operator-sdk for latest version}
227-
</version>
228-
</dependency>
229-
```
230-
231-
Create an Application, Quarkus will automatically create and inject a `KubernetesClient` (
232-
or `OpenShiftClient`), `Operator`, `ConfigurationService` and `ResourceController` instances that your application can
233-
use. Below, you can see the minimal code you need to write to get your operator and controllers up and running:
234-
235-
```java
236-
237-
@QuarkusMain
238-
public class QuarkusOperator implements QuarkusApplication {
239-
240-
@Inject
241-
Operator operator;
242-
243-
public static void main(String... args) {
244-
Quarkus.run(QuarkusOperator.class, args);
245-
}
246-
247-
@Override
248-
public int run(String... args) throws Exception {
249-
operator.start();
250-
Quarkus.waitForExit();
251-
return 0;
252-
}
253-
}
254-
```
255-
256-
### Spring Boot
257-
258-
You can also let Spring Boot wire your application together and automatically register the controllers.
259-
260-
Add [this dependency](https://search.maven.org/search?q=a:operator-framework-spring-boot-starter) to your project:
261-
262-
```xml
263-
264-
<dependency>
265-
<groupId>io.javaoperatorsdk</groupId>
266-
<artifactId>operator-framework-spring-boot-starter</artifactId>
267-
<version>{see https://search.maven.org/search?q=a:operator-framework-spring-boot-starter for
268-
latest version}
269-
</version>
270-
</dependency>
271-
```
272-
273-
Create an Application
274-
275-
```java
276-
277-
@SpringBootApplication
278-
public class Application {
279-
280-
public static void main(String[] args) {
281-
SpringApplication.run(Application.class, args);
282-
}
283-
}
284-
```
285-
286-
#### Spring Boot test support
33+
* Support For Intelligent Error Handling
28734

288-
Adding the following dependency would let you mock the operator for the tests where loading the spring container is
289-
necessary, but it doesn't need real access to a Kubernetes cluster.
35+
For all features and their usage see the [related section on the website](https://javaoperatorsdk.io/docs/features).
29036

291-
```xml
37+
## Related Projects
29238

293-
<dependency>
294-
<groupId>io.javaoperatorsdk</groupId>
295-
<artifactId>operator-framework-spring-boot-starter-test</artifactId>
296-
<version>{see https://search.maven.org/search?q=a:operator-framework-spring-boot-starter for
297-
latest version}
298-
</version>
299-
</dependency>
300-
```
39+
Operator SDK plugin: https://github.com/operator-framework/java-operator-plugins
30140

302-
Mock the operator:
41+
Quarkus Extension: https://github.com/quarkiverse/quarkus-operator-sdk
30342

304-
```java
30543

306-
@SpringBootTest
307-
@EnableMockOperator
308-
public class SpringBootStarterSampleApplicationTest {
30944

310-
@Test
311-
void contextLoads() {
312-
}
313-
}
314-
```

‎docs/documentation/faq.md

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -5,3 +5,10 @@ layout: docs
55
permalink: /docs/faq
66
---
77

8+
## Q: How can I access events?
9+
In the v1.* version events were exposed to `Reconciler` (in v1 called `ResourceController`). This
10+
included events (Create, Update) of the custom resource, but also events produced by Event Sources. After
11+
long discussions also with developers of golang version (controller-runtime), we decided to remove access to
12+
these events. We already advocated to not use events in the reconciliation logic, since events can be lost.
13+
Instead reconcile all the resources on every execution of reconciliation. On first this might sound a little
14+
opinionated, but there was a sound agreement between the developers that this is the way to go.

‎docs/documentation/features.md

Lines changed: 25 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -281,6 +281,31 @@ following attributes are available in most parts of reconciliation logic and dur
281281

282282
For more information about MDC see this [link](https://www.baeldung.com/mdc-in-log4j-2-logback).
283283

284+
## Automatic generation of CRDs
285+
286+
Note that this is feature of [Fabric8 Kubernetes Client](https://github.com/fabric8io/kubernetes-client) not the JOSDK. But it's worth to mention here.
287+
288+
To automatically generate CRD manifests from your annotated Custom Resource classes, you only need to add the following
289+
dependencies to your project:
290+
291+
```xml
292+
293+
<dependency>
294+
<groupId>io.fabric8</groupId>
295+
<artifactId>crd-generator-apt</artifactId>
296+
<scope>provided</scope>
297+
</dependency>
298+
```
299+
300+
The CRD will be generated in `target/classes/META-INF/fabric8` (or in `target/test-classes/META-INF/fabric8`, if you use
301+
the `test` scope) with the CRD name suffixed by the generated spec version. For example, a CR using
302+
the `java-operator-sdk.io` group with a `mycrs` plural form will result in 2 files:
303+
304+
- `mycrs.java-operator-sdk.io-v1.yml`
305+
- `mycrs.java-operator-sdk.io-v1beta1.yml`
306+
307+
**NOTE:**
308+
> Quarkus users using the `quarkus-operator-sdk` extension do not need to add any extra dependency to get their CRD generated as this is handled by the extension itself.
284309
285310

286311

‎docs/documentation/getting-started.md

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -20,7 +20,8 @@ You can read about the common problems what is this operator framework is solvin
2020
## Getting Started
2121

2222
The easiest way to get started with SDK is start [minikube](https://kubernetes.io/docs/tasks/tools/install-minikube/) and
23-
execute one of our [examples](https://github.com/java-operator-sdk/samples/tree/main/mysql-schema)
23+
execute one of our [examples](https://github.com/java-operator-sdk/samples/tree/main/mysql-schema).
24+
There is a dedicated page to describe how to [use samples](/docs/using-samples).
2425

2526
Here are the main steps to develop the code and deploy the operator to a Kubernetes cluster. A more detailed and specific
2627
version can be found under `samples/mysql-schema/README.md`.

0 commit comments

Comments
 (0)