Sharing the experience about how to deploy stateful service within Kubernetes by CoreOS Operator

1. 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
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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...
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4. Manage Production Service
4
Stateless Stateful
Setup
Scale Out/Up
Backup
Upgrade
Operation

5. Kubernetes Operator by CoreOS
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6. 6
Controller/Resource
Kubernetes Operator
Operator Framework
Demo
Reflection

7. 7
Controller/Resource
Kubernetes Operator
Operator Framework
Demo
Reflection

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
▪ ...
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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
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11. Custom Controller & Resource
▪ Apparently, Origin Controller & Resource Cannot
Fulfill.
▪ Hence, Kubernetes Support Custom Controller &
Resource
▪ It Allows Us to Extend Kubernetes
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12. 12
Controller/Resource
Kubernetes Operator
Operator Framework
Demo
Reflection

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
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14. What is Kubernetes Operator?
14
An Operator is a Domain Specific Controller

15. Operation of Stateless Service
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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

17. 17
Controller/Resource
Kubernetes Operator
Operator Framework
Demo
Reflection

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
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19. Operator SDK
19Awesome Operators

20. Operator Lifecycle Manager
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21. Operator Metering
Just Release Alpha Several Days Ago...
▪ Cluster’s CPU and Memory Reporting
▪ Infrastructure-as-a-Service (IaaS) Costs and
Customized Metrics
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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
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23. 23
Controller/Resource
Kubernetes Operator
Operator Framework
Demo
Reflection

24. Prometheus Operator
24Ref

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

26. 26
Controller/Resource
Kubernetes Operator
Operator Framework
Demo
Reflection

27. Operator is just a Controller + a CRD ?!
▪ https://news.ycombinator.com/item?id=16968873
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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
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29. Good Old Days V.S. Kubernetes
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GNU/Linux
Ref
ELF Binaries Config in /etc
apt, yum, etc
Chef, Puppet, Ansible
Kubernetes
Images K8S Object
Helm
Operator Framework

30. 30
THANKS!
ANY QUESTIONS?