Lviv DevOps Conference 2019 ОЛЕГ МАЦЬКІВ «Crash course on Operator Framework» Телеграм канал: https://t.me/GoDevOpsEvent Фейсбук сторінці: https://www.facebook.com/godevopsevent/ Сайт: https://devopsconf.org/

1. Crash course on Operator Framework
Oleg Matskiv, Red Hat, Czech Republic

2. OperatorOPS the future of
Kubernetes operations

4. Crash course on Operator Framework
Oleg Matskiv, Red Hat, Czech Republic

5. What is an operator?
• An Operator is a method of packaging, deploying and
managing a Kubernetes application.
• A Kubernetes application is an application that is both
deployed on Kubernetes and managed using the Kubernetes
APIs.
• The GOAL of an Operator is to put operational knowledge
into software.

6. History lesson
• CoreOS introduced Operator pattern in 2016
• Initially etcd operator and Prometheus operator
• Operator Framework introduced in May 2018

7. Operator Framework

8. Operator SDK
• A Go lang library
• import github.com/operator-framework/operator-sdk/
• CLI tool
• $ operator-sdk -h
• Wrappers for Helm charts and Ansible playbooks

9. How to use SDK CLI
• $ operator-sdk new app-operator
• $ operator-sdk add api
• --api-version=pgsql.com/v1alpha1 --kind=PostgreSQL
• $ operator-sdk add controller
• --api-version=pgsql.com/v1alpha1 --kind=PostgreSQL

10. CRD & CR
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
name: postgresqls.db.com
spec:
group: pgsql.com
version: v1alpha1
names:
kind: PostgreSQL
...
apiVersion: pgsql.com/v1alpha1
kind: PostgreSQL
metadata:
name: example-postgres
spec:
replicas: 3
logLevel: warning

11. Operators controller
Observe
(Watch)
Evaluate
(Compare state)
Act

12. Development workflow
● Code
● Update generated code, CRD, roles, etc.
● Run
● Test
● Build container image
● Publish

13. Operator Framework

14. Operator Metering
● A tool for metrics collection, storage and reporting
● Queries data from Prometheus and stores in Presto
database
● Reports are defined in SQL and output CSV
● AWS Billing integration
● Custom metrics exposed by operators = many use cases

15. Operator Framework

16. Operator Lifecycle Manager
● Extends Kubernetes to provide a declarative way to install,
manage, and upgrade operators and their dependencies
● Operators are described via ClusterServiceVersion
● CSVs are sourced from application registry (quay.io)

17. ClusterServiceVersion
apiVersion: operators.coreos.com/v1alpha1
kind: ClusterServiceVersion
metadata:
name: postgresql.9.7.2
annotations:
categories: Databases
containerImage: quay.io/abc/postgresql:9.7.2
description: Cool PostgreSQL operator
spec:
displayName: PostgreSQL
version: 9.7.2
replaces: postgresql.9.7.1
// continues

18. ClusterServiceVersion
customresourcedefinitions:
owned:
- name: postgresqls.db.com
version: v1alpha1
kind: PostgreSQL
install:
strategy: deployment
spec:
clusterPermissions:
...
permissions:
...
deployments:
...

19. OperatorSource
apiVersion: operators.coreos.com/v1
kind: OperatorSource
metadata:
namespace: openshift-marketplace
spec:
displayName: Community Operators
endpoint: 'https://quay.io/cnr'
publisher: Red Hat
registryNamespace: community-operators
type: appregistry

21. Operator capability levels
1) Basic install
2) Seamless upgrades
3) Full lifecycle
4) Deep insights
5) Auto pilot

22. Demo time

23. Questions ?

24. Tips for operator creation
● It’s software as any other, usual good practices apply
● Write unit tests
● Set owner references
● Learn how to use finilizers
● Use good security practices – minimal privilege, dedicated
SA

25. Tips for operator creation(2)
● Avoid having too many configuration options in CR
● Report status on the CR
● Avoid analysis paralysis – just get started:
● https://github.com/operator-framework/getting-started
● Interactive learning:
https://learn.openshift.com/operatorframework

26. Thank you!
Get in touch:
omatskiv@redhat.com
linkedin.com/in/matskiv