What DevOps exactly is and Why python is so interesting for DevOps engineers? Two of our experiences that python makes them easy.

1. Dev Ops
and Python
“Simple is better than complex!”

2. Who we are?
Salar Moghaddam
DevOps @ Digikala
working on Kubernetes
Bardia Heydari
DevOps @ Ario
working on Microservices

3. What is DevOps?
DevOps is the combination of cultural philosophies, practices,
and tools that increases an organization’s ability to deliver
applications and services at high velocity by unifying software
development (Dev) and software operation (Ops)

4. Software lifecycle
CodeBuild
Test
Package
Release
Configure
Monitor

5. DevOps Practices
● Continuous Integration
● Continuous Delivery
● Microservices
● Infrastructure as Code
● Monitoring and Logging
● Communication and
Collaboration
Continuous integration is a
software development practice
where developers regularly
merge their code changes into a
central repository, after which
automated builds and tests are
run.

6. DevOps Practices
● Continuous Integration
● Continuous Delivery
● Microservices
● Infrastructure as Code
● Monitoring and Logging
● Communication and
Collaboration
Continuous delivery is a software
development practice where
code changes are automatically
built, tested, and prepared for a
release to production.

7. DevOps Practices
● Continuous Integration
● Continuous Delivery
● Microservices
● Infrastructure as Code
● Monitoring and Logging
● Communication and
Collaboration
The microservices architecture is
a design approach to build a
single application as a set of
small services.

8. DevOps Practices
● Continuous Integration
● Continuous Delivery
● Microservices
● Infrastructure as Code
● Monitoring and Logging
● Communication and
Collaboration
Infrastructure as code is a
practice in which infrastructure is
provisioned and managed using
code and software development
techniques, such as version
control and continuous
integration. The cloud’s It enables
to interact with infrastructure
programmatically, and at scale.

9. DevOps Practices
● Continuous Integration
● Continuous Delivery
● Microservices
● Infrastructure as Code
● Monitoring and Logging
● Communication and
Collaboration
Organizations monitor metrics
and logs to see how application
and infrastructure performance
impacts the experience of their
product’s end user. Active
monitoring becomes increasingly
important as services must be
available 24/7 and as application
and infrastructure update
frequency increases.

10. Sentry (Monitoring)
Unittest, PyTest, Nose (Testing)
Locust (Testing)
Elastic APM (Monitoring)
Fabric (Deployment)
Ansible (Configuration)
SaltStack (Configuration)
Johnny-Cache, Cacheops (Caching)
Tool chain

11. Our experience:
With python of course... :)

12. Load/Stress Testing
Locust is a great tool:
● Distributed
● Scenario-based
But:
Scenario is hard coded in slaves…

13. Locust file? Errr.... #$!!
from locust import Locust, TaskSet
def my_first_scenario(l):
l.client.get("/")
def my_second_scenario(l):
l.client.get("/product/1")
class MyTaskSet(TaskSet):
tasks = [my_first_scenario, my_second_scenario]
class MyLocust(Locust):
task_set = MyTaskSet

14. Python helps ^__^
def my_start_hatching_handler(*args, **kw):
c = get_config()
MyTaskSet.tasks = [get_urls_task_callable(c, url) for url in c.urls]
events.locust_start_hatching += my_start_hatching_handler
def get_urls_task_callable(c, url):
def f(l):
l.client.get(url, headers=c.headers)
return f
class MyTaskSet(TaskSet):
tasks = []
class WebsiteUser(HttpLocust):
task_set = MyTaskSet

15. Deploy manually? :/
from fabric.api import env, run
env.hosts = ['host1', 'host2', 'host3', 'host4', 'host5', 'host6', 'host7' ]
def deploy_locust_slaves ():
get_processor_count = run('grep -c ^processor /proc/cpuinfo' )
for i in range(int(get_processor_count .stdout)):
run('docker run -d --name locust_slave_{} registry.ario.games/locustslave' .format(i+1))

16. Let’s build
docker
another way
:)

17. What docker do?
● Overlay storage (AUFS)
● Snapshot (Commit)
● Userspace isolation
● Resource limitation (Cgroups)
● Process management (Start, Stop, Restart, Kill, Rm)
● Network isolation (Bridge, Host, Nat, PAT, etc)
● CI/CD (Dockerfile, Multi staging)

18. Alternatives
● LVM for Overlay storage and Snapshot (Commit)
● Chroot for Userspace isolation
● Process management and Resource limitation
● Linux(!) for Network isolation
● Salt for CI/CD (Dockerfile, Multi staging)

19. LVM

20. LVM commands
● Pvcreate /dev/sdb1 /dev/sdc1 /dev/sdd1
● Vgcreate debian /dev/sdb1 /dev/sdc1 /dev/sdd1
● Lvcreate debian -n percona -L20g
● Mkfs.ext4 /dev/mapper/debian-percona
● /dev/mapper/debian-percona /var/lib/machines/percona ext4 default 0 0
● Mouant -a

21. Let’s do it
with salt!

22. Chroot

23. Chroot commands
● debootstrap --variant=minbase --include=systemd,dbus,curl,gnupg --arch amd64
stretch /var/lib/machines/{{ service }} http://ftp.debian.org/debian/
● Mount dev proc sys …
● Schroot --user root -D /var/lib/machines

24. Systemd-nspawn commands
● Systemctl restart systemd-nspawn@nginx
● Systemctl stop systemd-nspawn@nginx
● Systemctl start systemd-nspawn@nginx
● Systemctl enable systemd-nspawn@nginx
● Machinectl list, shell, login, ...

25. Let’s do it
with salt!

26. Install
Services

27. Thank you :)