介紹 Immutable infrastructure 概念，並以 OpenStack Kolla 為例子，說明如何使用 docker 和 ansible 來實作 immutable instructure

1. Immutable Infrastructure
Kuo-tung Kao

2. 簡介
任職於 inwinstack
過去的迎廣科技雲端應用研發中
心
OpenStack contributor
kjellytw at gmail dot com
http://www.blackwhite.tw/

3. 大綱
Immutable infrastructure 介紹
為什麼會有 immutable infrastructure?
immutable infrastructure 是什麼
immutable infrastructure 的缺點
OpenStack Kolla 如何實現 Iimmutable
infrastructure
名詞解釋：OpenStack, Docker, Ansible, OpenStack
Kolla
OpenStack Kolla 實做

4. 為什麼會有 immutable infrastructure?
減輕 operator 的工作
減少無紀錄的環境修改
更容易升級 / 降級
不容易升級失敗
升級失敗也可以快速還原

5. What’s the Iimmutable
Iinfrastructure
Don’t modify image manually
Create new image when something changes

6. System Infrastructure is divided into "data"
and "other".
"Other" are replaced at every deployment.
"Other" are modifed with version controll.
"Other" include “config”, “program”,
“environment”.
Package “other” using
Container

7. Running
Container V1
volume
Running
Container V2
volume
Stopped
Container V1
Running
Container V1
volume
Stopped
Container V2
upgrade downgrade

8. Immutable Infrastructure Advantage
Atomic deployments
Easy to upgrade
Easy to downgrade
Fault recovery
Easy to track change

9. Immutable Infrastructure Downside
Create new image when something changes

10. OpenStack
Open source software for creating private
and public clouds.
OpenStack software controls large pools of
compute, storage, and networking
resources throughout a datacenter,
managed through a dashboard or via the
OpenStack API.

11. Docker
Container
Llighter, fast than hypervistor
Build envirenment from Dockerfile
Version Controll
Support named volume

12. Dockerfile Demo

13. Docker - run container
docker run -e MYSQL_ROOT_PASSWORD=pass
-d mysql:5.7.12

14. Ansible
Deployment tool
Interpret
Yaml
Jinja2
Easy to write your own module in Python
Aagentless

15. Aansible Demo Sscript

16. Aansible Demo Sscript

17. OpenStack Kolla
Deploy OpenStack using Docker and Ansible
Support Ceph
A little downtime when upgrading
Easy to upgrade/downgrade
Rapid Deployment

18. How to deploy OpenStack using Kolla
tools/build.py -t binary -b centos
tox -e genconfig
sudo cp -rf etc/kolla /etc
#modify /etc/kolla/globals.yaml
tools/generate_passwords.py
tools/kolla-ansible pull #optional
tools/kolla-ansible deploy

19. Kolla Code Structure
docker:
build image
ansible:
generate openstack config
run container

20. 1.Encode the configuration into the build of
the container
2.Encode the configuration into environment
3.Create the configuration file that the
OpenStack service runs against outside the
container
4.Encode the configuration file generated by
the deployment tool into a JSON blob which

21. Kolla Code Structure

22. Kolla - dockerfile, base
Run the same command in
every container

23. Kolla - docker, base
the file is generated by
kolla_set_configs.

24. Kolla - dockerfile, heat-api

25. Create database schema when
KOLLA_BOOTSTRAP is set

26. Kolla - ansible, deploy, deploy.yaml

27. bootstrap.yaml
Create mysql databae using Ansible

28. Kolla - ansible, deploy,
bootstrap_service.yaml
Set env var,
KOLLA_BOOT
STRAP

29. Kolla - ansible, deploy, start.yaml

30. Kolla - ansible, deploy, heat-
api.json.j2

31. Kolla - ansible, upgrade,
bootstrap_service.yaml

32. 結論
Immutable infrastructure 讓佈署更容易
容易升級 / 降級
當升級失敗時，能夠快速還原
Kolla 和其他佈署方法相比，擁有快速佈署、快
速升級降級的優點

33. 參考資料
https://sdake.io/2015/11/11/the-tldr-on-
immutable-infrastructure/

34. Q&A

35. Question
用Kolla佈OpenStack, 所謂Downtime很小是因為
在建新的image, 舊的系統仍正在service, total
upgrading 時間仍然一樣還試?

36. Answer
在升級時，你可以事先將 image 建置好。等所
有 image 都建置好後，再進行升級動作。在
還沒執行 Ansible 腳本前，舊的系統依舊正常
運作，不會有任何影響
升級系統時，安裝套件很花時間。而 kolla 將
這時間轉嫁到 build image，而 build image
不會影響原本系統。這就是 kolla 可以快速升
級、快速佈署的原因

37. Question
用Kolla佈OpenStack,適合用在企業的部屬嗎?

38. Answer
目前能做的客製化部分不夠多，所以不一定滿
足不同的企業環境需要。不過如果你能夠修
改 ansible 腳本，那麼有助於你突破一些限制
( cinder multi backend 等)
未來 kolla 會支援 kubernetes 。或許可以等到
kolla 支援 kubernetes 在導入企業。
OpenStack 跑在 kubernetes 將會更強大