In this session, Nico will talk about Helm and Operators as well as the battle between them. If you ever ask yourself one of the following questions, this talk is the right one for you: "Do I have to decide?" "Do I need to learn both?" "What are the best tools for my use-case?" In short: There is no battle. Both tools have different scopes. Nico will talk about the pros and cons, and what the projects themselves focus on. Join his talk to learn more!

1. Helm vs Operators – Do I Need to Decide?
DevOpsCon Berlin, June 2021

2. Nico Meisenzahl
• Senior Cloud & DevOps Consultant at white duck
• Microsoft MVP, Docker Community Leader &
GitLab Hero
• Container, Kubernetes, Cloud-Native & DevOps
© white duck GmbH 2021
Phone: +49 8031 230159 0
Email: nico.meisenzahl@whiteduck.de
Twitter: @nmeisenzahl
LinkedIn: https://www.linkedin.com/in/nicomeisenzahl
Blog: https://meisenzahl.org

3. Agenda
• Do I need to decide?
• How do Helm and Operators differ?
• Real-world examples
• How to build an Operator
© white duck GmbH 2021

4. Do I need to decide?
© white duck GmbH 2021

5. Do I need to decide?
No!
We need different tools and methods to tackle different use
cases. They can also complement each other.
These use cases range from installing a small app to
operating a complex stateful application.
© white duck GmbH 2021

6. What is Helm?
• “The package manager for Kubernetes”
• simplifies our application deployments by focusing on
templatization, reusability
• we can use it for our own apps or benefit from a big
ecosystem
Note: Helm is just one (the most common) example of a
variety of similar tools.
© white duck GmbH 2021

7. What Helm helps with
• allows us to define, package, customize our applications
• supports us installing, upgrading and deleting stateless
applications
• enables us to start quickly
• provides us with support for Day-1 operations
Helm does not focus on managing/operating an application.
© white duck GmbH 2021

8. Application lifecycle
© white duck GmbH 2021
https://www.meshcloud.io/2020/06/08/cloud-landing-zone-lifecycle-explained/

9. What we still need help with
• maintaining our applications
• housekeeping tasks
• optimizing our exiting applications
• upgrading
• stateful applications
• complex applications with dependencies
• implementing backups, failure recovery
Basically, everything that concerns Day-2 operation.
© white duck GmbH 2021

10. The Operator pattern
… is an application-specific controller that extends the
Kubernetes API to create, configure, and manage instances
of complex stateful applications on behalf of a Kubernetes
user.
The Operator pattern aims to capture the main goal of a
human operator managing a service or set of services.
© white duck GmbH 2021

11. Where an Operator can help
• package human operational knowledge into code
• DRY (don’t repeat yourself)
• automate maintenance & complex operational tasks
• deployments & scaling
• configuration changes, rollouts, upgrades & testing
• backups & restores
• tasks can be translated into declarative input
• diff, act, observe (declarative / desired state)
Offers Kubernetes-native way to automate Day-2 operations.
© white duck GmbH 2021

12. What exactly is an Operators?
• Custom Resource
• a Custom Resource (CR) is an extension of the Kubernetes API
defined by a Custom Resource Definition (CRD)
• Controller
• a Controller monitors the CR type and initiates application-
specific actions to adjust the current state of the resource to the
desired state.
• the Controller runs as a containerized workload within the
Kubernetes cluster
© white duck GmbH 2021

13. Operator lifecycle
© white duck GmbH 2021
https://medium.com/swlh/kubernetes-operator-for-beginners-what-why-how-21b23f0cb9b1

14. Operator vs. Custom Controller
• identical concepts with different domains
• Custom Controller
• understands only Kubernetes’s native abstractions such as
Pod, Deployment, Service, …
• Operator
• Controllers that are part of an Operator also understand
Custom Resource abstractions that the Operator has
introduced
© white duck GmbH 2021

15. When to use Operators
• operate stateful third-party applications
• manage your own complex or stateful applications
• introduce abstraction
• “something” as a service as part of a developer platform
• external resources
© white duck GmbH 2021

16. Some examples (third party)
• Prometheus Operator
• manage Prometheus, Alertmanager, and related components
• Strimzi Kafka Operator
• run and operate Apache Kafka clusters on Kubernetes in various
deployment configurations
• Elastic Cloud on Kubernetes (ECK)
• orchestrate Elastic applications (Elasticsearch, Kibana, APM Server,
…) on Kubernetes
• Crossplane
• provision and manage cloud infrastructure and services
© white duck GmbH 2021

17. Build your own Operator
• using a Kubernetes Client library
• https://github.com/kubernetes/sample-controller
• choose from a variety of tools and frameworks
• kubebuilder
• Operator Framework
• Shell-operator
• KUDO
© white duck GmbH 2021
https://hazelcast.com/blog/build-your-kubernetes-operator-with-the-right-tool/

18. kubebuilder
• provides powerful libraries and tools to simplify building
and publishing Kubernetes APIs from scratch
• focuses on Golang
• fully flexible
• is maintained by Kubernetes SIG API Machinery
© white duck GmbH 2021

19. Operator Framework
• Operator SDK
• software development kit for building Operators
• scaffolding and more higher-level framework with large feature set
• supporting Helm, Ansible and Golang
• Operation Lifecycle Manager (OLM)
• helps install, update, and manage the lifecycle of Operators
• OperatorHub.io
• catalog hosting existing Operators
• by RedHat
© white duck GmbH 2021

20. Shell-operator
• running event-driven scripts in a Kubernetes cluster
• bash, python, kubectl, …
• easy to start with
• ops-focused
• triggered by Kubernetes events, scheduled, or start up
• webhook machinery for AdmissionReview requests & others
• is based on an “universal” controller
• by Flant
© white duck GmbH 2021

21. KUDO
• Kubernetes Universal Declarative Operator
• no coding required
• define Operators as templated YAML manifests
• based on kubebuilder and other community projects
• Operator Repository
• https://github.com/kudobuilder/operators
• also based on an “universal” controller
© white duck GmbH 2021

22. You have to decide
• are you running…
• stateless or stateful/complex applications?
• stateful third-party applications? Do they provide an Operator?
• Operators…
• can help but also introduce complexity
• you need to commit to maintain the Operator code
• have a different focus than Helm; each has strengths and
weaknesses
• Operators & Helm can also complement each other
© white duck GmbH 2021

23. Questions?
Slides: https://www.slideshare.net/nmeisenzahl
Nico Meisenzahl (Senior Cloud & DevOps Consultant)
Phone: +49 8031 230159 0
Email: nico.meisenzahl@whiteduck.de
Twitter: @nmeisenzahl
LinkedIn: https://www.linkedin.com/in/nicomeisenzahl
Blog: https://meisenzahl.org
© white duck GmbH 2021