Kubernetes Summit 2018 - Kubernetes: Stateless -> Stateful
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This document discusses Kubernetes operators and the operator framework. It defines an operator as software with specific application knowledge that extends Kubernetes through custom controllers and resources. It provides examples of stateful services that require operators to manage tasks like setup, scaling, backups, and upgrades. The operator framework introduced by CoreOS aims to make it easier to build operators using tools like the Operator SDK and Operator Lifecycle Manager. It also gives a demonstration of the Prometheus and Elasticsearch operators.
Kubernetes Summit 2018 - Kubernetes: Stateless -> Stateful
- 2. HELLO! I AM smalltown (Tom Tsai) I am here because I want to share something with you You can find me at smalltown@awsug.tw 2
- 3. Stateful Service ▪ Replication Setup, e.g. MongoDB, MySQL ▪ Cluster Management, e.g. Etcd, Kafka, ElasticSearch ▪ Scale Out, Scale Up ▪ Upgrade ▪ Data Backup ▪ Other Operation Job... 3
- 4. Manage Production Service 4 Stateless Stateful Setup Scale Out/Up Backup Upgrade Operation
- 5. Kubernetes Operator by CoreOS 5
- 8. Kubernetes Controller & Resource 8 Controller Resource K8S Resource: - Deployment - Replicaset - Pod - ... Action: - Create - Update - Delete
- 9. Stateless Service Origin Controller and Resource Enough to Handle ▪ Blue/Green Deployment ▪ Auto-Healing ▪ Scale Out, Scale Up ▪ ... 9
- 10. Stateful Service Example: Add One New Etcd Member into Cluster ▪ Create a DNS Name for the New Etcd Member ▪ Launch the New Etcd Instance ▪ Use the Etcd Administrative Tools to Tell the Existing Cluster About this New Member 10
- 11. Custom Controller & Resource ▪ Apparently, Origin Controller & Resource Cannot Fulfill. ▪ Hence, Kubernetes Support Custom Controller & Resource ▪ It Allows Us to Extend Kubernetes 11
- 13. What is Kubernetes Operator? ▪ An Operator is a Software with Specific Application Knowledge ▪ Extends the Kubernetes through Custom Controller/Resource ▪ Enable Users to Create, Configure, and Manage Applications 13
- 14. What is Kubernetes Operator? 14 An Operator is a Domain Specific Controller
- 15. Operation of Stateless Service 15 kubectl ReplicaSet app=web, env=prod Pod app=web env=prod scale up desired=3 count=1 kubectl ReplicaSet app=web, env=prod Pod app=web env=prod desired=3 count=3
- 16. Operation of Stateful Service (Operator) 16 backup kubectl etcd Operator app=3.0.13 size=3 Pod app=web env=prod backup-tool interval=300s
- 18. Operator Framework The Concept of Kubernetes Operator is Introduced by CoreOS at Nov. 2016, then releasing Operator Framework at May 2018 ▪ Operator SDK ▪ Operator Lifecycle Manager ▪ Operator Metering 18
- 21. Operator Metering Just Release Alpha Several Days Ago... ▪ Cluster’s CPU and Memory Reporting ▪ Infrastructure-as-a-Service (IaaS) Costs and Customized Metrics 21
- 22. Although There is Operator Framework... ▪ It’s Easy to Complete the First Operator by Following the Get Started, But Before Starting... ▪ Recommend to Realize Kube Controller Flow, And Custom Controller/Resource Implement Method ▫ Ref 1 ▫ Ref 2 22
- 25. ElasticSearch Operator 25 Centralized Log ASAP ● Install Filebeat in each server ● Prepare Logstash indexer ● Setup Elasticsearch ○ Kibana ○ Master, Data, Ingest Node ○ Replicas ○ Backup ○ ... Demo Repository https://goo.gl/zk5SB1
- 27. Operator is just a Controller + a CRD ?! ▪ https://news.ycombinator.com/item?id=16968873 27
- 28. helm-app-operator-kit Installing a Custom Helm-Based Application ▪ https://github.com/operator-framework/helm-app-op erator-kit ▪ Leverage a pre-existing Helm Chart to Deploy Kubernetes as a Operator 28
- 29. Good Old Days V.S. Kubernetes 29 GNU/Linux Ref ELF Binaries Config in /etc apt, yum, etc Chef, Puppet, Ansible Kubernetes Images K8S Object Helm Operator Framework