Announcing KUDO 0.3.0

We are proud to announce the release of KUDO v0.3.0! This release introduces a new package format, a package repository, and introduces a test harness to help with end-to-end testing. It also deprecates the term "Framework" in favor of "Operator".

What is KUDO?

Kubernetes Universal Declarative Operator (KUDO) provides a declarative approach to building production-grade Kubernetes Operators covering the entire application lifecycle. An operator is a way to package and manage a Kubernetes application using Kubernetes APIs. Building an Operator usually involves implementing a custom resource and controller, which typically requires thousands of lines of code and a deep understanding of Kubernetes. KUDO instead provides a universal controller that can be configured via a declarative spec (YAML files) to operate any workload.

Release Highlights

Switch from Framework to Operator

Framework was the term the project previously used to represent a service that KUDO "the operator" would be instrumented to be an operator for. The intention was to bring clarity by introducing a new term. It was thought that the new term would allow for more accuracy in technical communication by reducing the overloading of the term operator. For some it caused more confusion and almost always resulted in the need for explanation. We have abandoned the term completely resulting in a breaking change to the CRDs.

All previous concepts and required objects using the word Framework have been replaced with Operator, resulting in Operator and OperatorVersion in the type definition.

This will result in some overloading of the term operator, but aligns better with the eco-system. The running KUDO controller is an operator that manages operators built with KUDO's packaging format. In the future, this will be expanded with support for Helm charts (v0.4.0), other packaging formats, existing operators, and beyond. KUDO's mission is to enable easy, declarative Day 2 operations and API management for complex applications, no matter how they were originally built.

Package Format

KEP-10 for the package manager is underway, with this release providing two features; package repository and a package format.

The general format allows for a number of files, but starts with an operator.yaml. A common layout might be:

operator.yaml
params.yaml
templates/
     <additional files>.yaml

The operator.yaml defines the operator and its plans. params.yaml defines the params to be used through all templated files. While the templated files are defined under the templates folder. The templated files are referenced in the operator.yaml file. The zookeeper operator provides a good example.

These package files are grouped together in a folder or subfolder or can be tarred together in a tgz file providing a couple of ways to install an operator.

Package Installation Options

Introduced with this release are two ways to install an operator to KUDO. The first is designed for operator developers which is to install from the local filesystem. This can be either a folder with the operator package files or a tarball of those files.

To install an operator from a folder run:

kubectl kudo install ./my-kafka-folder

To install from a tarball run:

kubectl kudo install kafka.tgz

This release also introduces a repository which allows for automatic discovery of operators to be installed. To install from the repository run:

kubectl kudo install kakfa

Note: The order of operation when installing an operator is to check the local filesystem first, then to query the repository.

Skip Instance

kudoctl install now supports --skip-instance flag which skips installing an Instance when installing Operator and OperatorVersions. This is useful in a testing scenario - we install all of the Operators and OperatorVersions but don't want to install the Instances until later.

Test Harness

The test harness outlined in KEP-8 has been implemented. The test harness provides a mechanism for operator developers to declaratively create end-to-end integration tests for their operators using only Kubernetes YAML. Example tests are provided for the zookeeper operator.

Operator Dependency Management Removed (For Now)

The proper handling of operator dependencies is more complex than first imagined / implemented. This fact was called out in Issue 438. For this reason we have removed the all-dependencies flag from kudoctl. This feature needs to be designed through the KEP process and will be implemented properly in the future.

Changelog

Additionally, the team closed dozens of issues related to bugs and performance issues.

To see the full changelog and the list of contributors who contribtued to this release, visit the Github Release page.

What's Next?

Now that KUDO v0.3.0 has shipped, the team will begin planning and executing on v0.4.0. The focus of v0.4.0 is to provide operator extensions to provide KUDO's sequencing logic to formats including Helm Charts and CNAB bundles. v0.4.0 will also focus on the operator release process for operators being released into the repository.

Get started with KUDO today. Our community is ready for feedback to make KUDO even better!