1. KOPF Kubernetes Operator Pythonic Framework SERGEY VASILYEV Twitter: @nolar (Zalando SE) Python Pizza Berlin, 23.08.2019

2. Kopf, a Kubernetes Operator Pythonic Framework Sergey Vasilyev Twitter: @nolar Zalando SE Python Pizza Berlin, 23.08.2019

3. About me ● My name is Sergey Vasilyev ○ https://twitter.com/nolar ● Sr. Backend Engineer in Zalando SE. ● Running ML apps & infra on Kubernetes for Zalando Pricing & Forecasting.

4. “Kubernetes is a container orchestrator”

5. Kubernetes under the hood

6. Extending Kubernetes: Custom Resource Definitions

7. Declaring a CRD ● ● ● ● ● ● Required: “group/version”. Required: kind/plural/singular names. Required: scope (“Namespaced”). Optional: short names (aliases). Optional: list formatting and columns. Optional: categories. $ kubectl apply -f examples/crd.yaml $ kubectl apply -f examples/obj.yaml

8. Extending Kubernetes: Controllers/Operators

9. Common use: an application-specific operator https://github.com/zalando-incubator/es-operator

10. Problem: infrastructure code hassle

11. MAKE A FRAMEWORK!

12. Kopf: simple spy-handlers ● ● ● As often, as the events arrive from K8s API. Raw payload, no interpretation. Fire-and-forget, ignore errors.

13. Kopf: convenient cause- & diff-handlers

14. Kopf: running from the development environment $ kopf run scripts.py [--verbose] And here we are! Creating: {'duration': '1m', 'field': 'value', 'items': ['item1', 'item2']} [2019-02-25 14:06:54,742] kopf.reactor.handlin [INFO ] [asf-preprocessing/kopf-example-1] Handler create_fn succeeded. [2019-02-25 14:06:54,856] kopf.reactor.handlin [INFO ] [asf-preprocessing/kopf-example-1] All handlers succeeded for creation. $ kubectl apply -f ../obj.yaml $ kubectl describe -f ../obj.yaml Name: kopf-example-1 ... Status: create_fn: Message: hello world Events: Type Reason Age From ---- ------ ---- ---- Normal Success 81s kopf Message ------- Handler create_fn succeeded.

15. Features ● ● ● ● Custom & built-in resources supported (crds, pods, services, etc). Agnostic to API clients: kubernetes-client, pykube-ng, raw HTTP, etc. Immediate reaction to changes and events. Predefined behavioural patterns: ○ ○ ○ ● Operator resilience: ○ ● Simple spy-handlers for event watching. Advanced cause & diff detection for actual change tracking. Retry-until-success approach to handlers. Restores its state on restarts. Operator testing toolkit (minimally sufficient).

16. Roadmap ● ● ● Cross-handler communication and state management. Cross-object interactions & relations (e.g. children pods of a parent resource). Per-object thread/task orchestration handlers. ● ● Code generation (CRDs/RBAC/Dockerfile/etc), verification, packaging. Integration with Operator Lifecycle Manager. ● Your suggestions? ;-)

17. Links ● ● ● ● ● Kopf sources: ○ https://github.com/zalando-incubator/kopf Kopf documentation: ○ https://kopf.readthedocs.io/ Kopf examples: ○ https://github.com/zalando-incubator/kopf/tree/master/examples Other Zalando operators: ○ https://github.com/zalando-incubator/es-operator ○ https://github.com/zalando/postgres-operator Me (Sergey Vasilyev): ○ https://twitter.com/nolar ○ https://www.linkedin.com/in/sergeyvasilyev/

18. THE END (questions — later)