DevOpsCon Berlin: Helm vs Operators – Do I Need to Decide?
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The document discusses the differences between Helm and operators in Kubernetes, emphasizing that both tools serve different purposes and can complement each other. Helm is primarily a package manager that simplifies application deployment, while operators manage complex stateful applications and automate day-2 operations. The document provides insights on when to use each tool, real-world examples, and guidance on building your own operator.
DevOpsCon Berlin: Helm vs Operators – Do I Need to Decide?
- 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