Site Reliability Engineering enables agility and stability. SREs use Software Engineering to automate themselves out of the Job. My advice, if you want to implement this change in your company is to start with action items, alter your training and hiring, implement error budgets, do blameless postmortems and reduce toil. https://events.drupal.org/dublin2016/sessions/sre-create-ultra-scalable-and-highly-reliable-systems

2. S.R.E.
create ultra-scalable and highly
reliable systems
Ricardo Amaro
DevOps - https://events.drupal.org/node/13519

3. Who am I?
@Drupal
@ricardoamaro
Portugal
Lisbon
Drupal
Community
Family
+8 years Drupal
90’s Linux Adopter
5 years at Acquia
Site Reliability Engineer,
Senior Tier2 Ops
https://drupal.org/user/666176

4. About Acquia Metrics
￮ Acquia Cloud:
○ # of Instances (17,200+)
○ # of Production Sites (54,000+)
○ # API Calls (3,000 + per sec)
○ # Of Availability Zones (20+)
○ # Of Regions (8)

5. We will talk about
A brief summary inspired on Google’s S.R.E. book
￮ What is S.R.E?
￮ Tenets of S.R.E.
￮ Reliability & Toil
￮ Error budget - keeping the Service Level Objective (SLO)
￮ Development & Operations
￮ Monitoring and Being On-Call
￮ Release Engineering
￮ Postmortem culture - Learning from failure

6. What is S.R.E.?

7. ➔ Term crafted by Google in 2003.
➔ When Ben Treynor was hired to run “production” and ended up
“applying software engineering to an operations function”
➔ Motivation: “as a software engineer, how would I want to invest my
time to accomplish a set of repetitive tasks?”
Site Reliability Engineering

8. ➔ SRE is taken seriously by major companies
Site Reliability Engineering
Microsoft
Apple
Amazon

9. SRE’s are engineers that...
➔ Apply the principles of computer science and engineering to
design and develop large, distributed computing systems.
➔ Write software for those systems alongside product developers.
➔ Build all additional pieces those systems need, like backups and
load balancing.
➔ Reuse old solutions for new problems.
Site Reliability Engineering

10. DevOps & S.R.E.
DevOps is a practice, which was coined around
2008, that encompasses automation of manual
tasks, continuous integration and continuous
delivery. It applies to a wide audience of
companies whereas SRE might be considered a
subset of DevOps that possesses additional skill
sets.
Source:
https://en.wikipedia.org/wiki/Site_reliability_engineering

11. Tenets of S.R.E.

12. Tenets of SRE
1. Ensuring a Durable Focus on Engineering
2. Pursuing Maximum Change Velocity
3. Monitoring
4. Emergency Response
5. Change Management
6. Demand Forecasting and Capacity Planning
7. Provisioning
8. Efficiency and Performance

13. ➔ Hire only coders
➔ Have Service Level Objectives (SLOs) for your service
➔ Measure and report performance against SLOs
➔ Use Error Budgets and gate launches on them
➔ Have a Common staffing pool for SRE and DEV
➔ Excess Ops work overflows to DEV team
➔ Cap SRE operational load at 50% and share 5% with the DEV team
➔ On-call teams at least 8 or 6 people in rotation, per product
➔ Maximum of 2 events per on-call shift
➔ Post mortem for every event
➔ Post mortems are BLAMELESS and focus on process and technology, not people
How to achieve S.R.E.
Treynor’s Action items
IMPORTANT
IMPORTANT

14. Reliability & Toil

15. The latest feature
or
That the product works?
What is most the important Feature of a product?

16. How about the “503” feature ?
...most important thing is that the product works!

17. “Reliability is the most fundamental feature of any product.”
Ben Treynor, Google’s VP for 24/7 Operations

18. The 80’s Waterfall software delivery model
Operations @customer
➔ *Provisioning
➔ *Installing
➔ *Upgrading
➔ *Maintaining
➔ *Backups/Restore
➔ *Scaling
Source: wikipedia

19. Then came the web...
● Software as a Service
● Platform as a Service
● Cloud computing
● ...
➔ Operations overhead not on the customer side
➔ Features could now be delivered faster
➔ Customer feedback important for product improvements
Product
Development
Ship Features
Operations
Users

20. Opposite rewarding conflicts
Objectives:
➔ Ship new features
➔ Launch new products
Objectives:
➔ Reliability & Availability
➔ Provision & Scale
Dev Ops

21. The problem: Toil*
*exhausting labour
➔ Manual
➔ Repetitive
➔ Automatable
➔ Tactical (Unplanned work)
➔ No enduring value
➔ O(n) with service growth
(not just “work I don’t like to do.”)

22. An Old Solution to Toil
Caption goes here
● Scale with bodies
In the old operations model, you throw
people at a reliability problem and keep
pushing (sometimes for a year or more)
until the problem either goes away or
blows up in your face.

23. Has your business succeeds
workload tends to infinity
(x) time
● Cap Ops Workload
Because if you are successful and your
business grows you need to reduce
errors and toil. Put a 50% cap on Ops
work and leave most of the SRE team
time for writing code and reduce Toil.
(y)customers/traffic
Workload/Toil over time

24. ➔ Keep operational work (i.e., toil) below 50% of each SREs time
➔ More than 50% of each SREs time is spent on:
◆ Engineering project work to reduce toil
◆ Add service features - improving reliability, performance,
utilization
➔ Improves career planning for the SRE
➔ Improves morale on the organization
➔ An SRE team can easily devolve into an Ops team if the 50% target
is broken
Why less Toil is Better?
S.R.E. - A modern solution
not bad...

25. S.R.E. - A modern solution
DEV + OPS
➔ This conflict is not inevitable
➔ The solution is: Error Budgets!
➔ Everyone agrees on an Error Budget (as we will explain next)
➔ SRE only prevents releases or Launches if the Error Budget is exceeded.
Dev Ops

26. error budget
keeping the SLO

27. ➔ SLO - Service level objective is agreed as a means of measuring the performance of the
Service Provider.
➔ SLA - Service Level Agreement specifies what service is to be provided, how it is
supported, times, locations, costs, performance, and responsibilities of the parties
involved. SLOs are specific measurable characteristics of the SLA such as availability,
throughput, frequency, response time, or quality.
➔ SLI - Service Level Indicator is a measure of the service level provided by a service
provider to a customer. SLIs form the basis of Service Level Objectives (SLOs), which in
turn form the basis of Service Level Agreements (SLAs).
SLO, SLA & SLI Terminology

28. What is an Error Budget?
The business or the product establishes Service Level Objectives (SLOs) for the system, based on
Service Level indicators such as error rate, availability or latency...
Error Budget
Example: A 99.9% availability SLO means that the service can be 0.1% unavailable, which is the error budget.
100% - 99.9% = 0.1%

29. ➔ 100% is the wrong reliability target for basically everything.
➔ Set a goal that acknowledges the trade-off and leaves an error budget
➔ Error budget can be spent on anything: launching features, etc.
➔ Error budget allows for discussion about how phased rollouts and 1%
experiments can maintain tolerable levels of errors.
➔ Goal of SRE team isn’t “zero outages” – SRE and product devs are incentive
aligned to spend the error budget to get maximum feature velocity.
➔ Out of Budget? No problems. Do more testing between releases.
How to obtain the Error Budget

30. ➔ This puts an incentive to developers that drives them to value stability (not just change)
➔ And gives control that drives SREs to permit change (not just stability)
➔ It forces decisions based on metrics, not politics- nor feelings, just data
Error Budget
A Self-regulating mechanism

31. Development &
Operations

32. ➔ Development and SRE teams share a
single staffing pool
◆ If all is Reliable Devs are
rewarded with teammates
◆ If Ops is overloaded, SREs are
contracted to support code
How are Development & Operations
teams organized?
Now tell me… Why should I hire you?

33. Systems, code…
Are you able to cook also?
➔ SREs are developer/sys-admin
hybrids
◆ They perform more Dev work as
things become stable
Development & Operations
Systems, code…
Are you able to cook also?

34. ➔ SRE can only spend up to 50% of their
time on ops work
➔ If operational load exceeds 50%, the ops
work overflows to Dev
➔ Allow SRE to move to other projects
Highly motivated and effective teamwork

35. Monitoring and Being
On-Call

36. ➔ Three valid kinds of monitoring output
◆ Alerts: human needs to take action immediately
● If you get a huge volume of critical email alerts disable them and stick with
paging
◆ Tickets: human needs to take action eventually
● On-call engineers can actually accomplish work when they aren’t being kept
up by pages at all hours. Ultimately, temporarily backing off on our alerts will
allow you to make faster progress toward a better service
◆ Logging: no action needed
Monitoring and taking action

37. ➔ Maximum of 2 events per 8–12hour on-call shift
➔ Handle the event accurately and quickly, clean up and restore
normal service
➔ Conducting postmortems
➔ If more than 2 events occur regularly per on-call shift,
problems can’t be investigated
➔ Pager fatigue also won’t improve with scale
➔ If they receive fewer than one event per shift, keeping them
on point is a waste of their time
Being On-Call

38. ➔ Monitoring should never require a human to
interpret any part of the alerting domain
➔ The four golden signals of monitoring are
latency, traffic, errors, and saturation.
Start to focus on these four
“Don’t suggest, expose!”
Dashboards

39. ➔ An engineer can only react with urgency a
few times a day before they get fatigued
➔ Every page should be actionable
➔ Every page response should require
intelligence
➔ Pages should be about a new problem or
an event that hasn’t been seen before
Pager fatigue
A serious a problem to be addressed

40. Root Cause Analysis: The Core of Problem
Solving and Corrective
by Duke Okes
https://www.amazon.com/Root-Cause-Analysis-Problem-Corrective/
dp/0873897641
Find and eliminate all root causes

41. ➔ When humans are really necessary, thinking and recording the best practices ahead
of time in a playbook or runbook improves 3x in the Mean Time To Repair (MTTR)
➔ SRE’s write and rely on on-call playbooks/runbooks
Example: http://docs.ansible.com/ansible/playbooks_intro.html
Playbooks/Runbooks

42. A healthy monitoring and alerting pipeline
should be simple and easy to reason about
Monitoring Conclusion
What do i do with this?
➔ Try always to have a high level stack overview
➔ Despite performance of services like databases
often must be performed on the system itself
➔ A dashboard might also be paired with a log, in
order to analyze historical correlations rapidly

43. Release Engineering

44. ➔ All activities in between regular development and delivery of a software product
to the end user:
◆ i.e., integration, build, test execution, packaging and delivery of software
➔ “Accelerating the path from development to operations”
➔ A part of the SRE team where some more seasoned members are transitioned
there to conduct this highly important task
➔ Is an internal service
What is Release Engineering?

45. 1. Use version control
2. Use the right building tool(s) for the job
3. Write simple and portable build files
4. Use a release process that is reproducible (CI process)
5. Use a package manager
6. Define upgrade process before reaching 1.0
7. Create detailed logs of changes made
8. Do “Canary”
9. Keep the big picture in mind
10. Apply these commands to yourself
10 Commandments of Release Engineering

46. Collaboration
developers, SRE’s and release engineers work together

47. Postmortem culture
Learning from failure

48. ➔ Document written for ALL significant incidents
➔ Non-paged incidents are even more valuable -
monitoring gaps
➔ Explain what happened in detail
➔ Find all root causes of the event
➔ Assign actions to correct the problem or improve how it
is addressed next time
What are Postmortems?
Postmortems?!

49. Postmortems Are Blameless!
➔ Use a blame free postmortem culture, with the
goal of exposing faults
◆ Apply engineering to fix these faults
◆ Try not just avoid or minimize them

50. Learn and teach with postmortems
Source: http://www.xkcd.com/1495/

51. SERIOUSLY: BLAMELESS!
The Field Guide to Understanding
Human Error
by Sidney Dekker
https://www.amazon.com/Field-Guide-Understanding-Human
-Error/dp/0754648265

52. Conclusions

53. The S.R.E. Google Book
and more resources
● https://g.co/SREBook
● There is now #SRE on @hangops
Slack. https://t.co/btPgSGkGNz to
join.

54. QUESTIONS!

55. Evaluate This Session
THANK YOU!
WHAT DID YOU THINK?
We are hiring:
https://www.acquia.com/careers/open-positions
https://events.drupal.org/node/13519