Yan Cui - Applying principles of chaos engineering to Serverless - Codemotion Berlin 2018
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The document discusses chaos engineering, particularly its application to serverless architectures, emphasizing the importance of controlled experiments to build confidence in system resilience. It outlines the steps to implement chaos experiments, including defining a steady state, injecting realistic failures, and disproving hypotheses while ensuring containment. The challenges of serverless architectures, such as configuration and error handling, are also highlighted, alongside strategies for managing failures effectively.
Yan Cui - Applying principles of chaos engineering to Serverless - Codemotion Berlin 2018
- 1. Applying principles of chaos engineering to Serverless Yan Cui @theburningmonk Berlin | November 20 - 21, 2018
- 2. Agenda What is chaos engineering? New challenges with serverless Applying latency injection to serverless Applying error injection to serverless
- 3. What is chaos engineering?
- 4. Chaos Engineering is the discipline of experimenting on a distributed system in order to build confidence in the system’s capability to withstand turbulent conditions in production. - principlesofchaos.org
- 5. Smallpox Earliest evidence of disease in 3rd Century BC Egyptian Mummy. est. 400K deaths per year in 18th Century Europe.
- 6. History of vaccination First vaccine was developed in 1798 by Edward Jenner. https://en.wikipedia.org/wiki/Edward_Jenner
- 7. History of vaccination First vaccine was developed in 1798 by Edward Jenner. WHO certified global eradication in 1980. https://en.wikipedia.org/wiki/Edward_Jenner
- 9. History of vaccination Vaccination is the most effective method to prevent infectious diseases.
- 10. History of vaccination Vaccination is the most effective method to prevent infectious diseases. Vaccines stimulate the immune system to recognise and destroy the disease before contracting it for real.
- 11. Chaos engineering Use controlled experiments to inject failures into our system.
- 12. Chaos engineering Use controlled experiments to inject failures into our system. Help us learn about our system’s behaviour and uncover unknown failure modes, before they manifest like wildfire in production.
- 13. Chaos engineering Use controlled experiments to inject failures into our system. Help us learn about our system’s behaviour and uncover unknown failure modes, before they manifest like wildfire in production. Lets us build confidence in its ability to withstand turbulent conditions.
- 14. Chaos Engineering is the vaccine to frailties in modern software.
- 15. Who am I? Principal Engineer at DAZN. AWS Serverless Hero. Author of Production-Ready Serverless* course by Manning. Blogger**, speaker. * https://bit.ly/production-ready-serverless ** https://theburningmonk.com
- 20. About DAZN Available in 7 countries - Austria, Switzerland, Germany, Japan, Canada, Italy and USA. Available on 30+ platforms.
- 21. About DAZN Available in 7 countries - Austria, Switzerland, Germany, Japan, Canada, Italy and USA. Available on 30+ platforms. Around 1,000,000 concurrent viewers at peak.
- 22. follow @dazneng for updates about the engineering team We’re hiring! Visit engineering.dazn.com to learn more. WE’RE HIRING!
- 23. Chaos engineering has an image problem
- 24. Chaos engineering has an image problem
- 25. Chaos engineering has an image problem Too much emphasis is on breaking things.
- 26. Chaos engineering has an image problem Too much emphasis is on breaking things. Easy to conflate the action of injecting failures with the payback.
- 27. Why did you break production?
- 28. Because I can!
- 29. Chaos engineering has an image problem The goal is to learn about the system and build confidence.
- 30. Chaos engineering has an image problem The goal is to learn about the system and build confidence. The goal is not to break things.
- 31. Chaos in practice 4 steps to start running chaos experiments yourself.
- 32. STEP 1. Define “steady state” aka. what does normal, working condition looks like?
- 33. this is not a steady state
- 34. Hypothesise steady state will continue in both control group & the experiment group ie. you should have a reasonable degree of confidence the system would handle the failure before you proceed with the experiment STEP 2.
- 35. Chaos in practice Explore unknown unknowns away from production.
- 36. Chaos in practice Explore unknown unknowns away from production. Experiments that graduate to production should be carefully considered and planned. You should have reasonable confidence in the system before running experiments in production.
- 37. Chaos in practice Treat production with the care it deserves. The goal is not to break things.
- 38. Chaos in practice If you know the system would break and you did it anyway, then it’s not a chaos experiment! It’s called being irresponsible.
- 39. STEP 3. Inject realistic failures e.g. server crash, network error, HD malfunction, etc.
- 42. STEP 4. Disprove hypothesis i.e. look for difference in steady state
- 43. Chaos in practice Look for evidence that steady state was impacted by the injected failure.
- 44. Chaos in practice Look for evidence that steady state was impacted by the injected failure. Address weaknesses before failures happen for real.
- 45. Containment Experiments needs to be controlled. The goal is not to break things.
- 46. Containment Ensure everyone knows what you are doing. Don’t surprise your teammates.
- 47. Containment Run experiments during office hours.
- 48. Containment Run experiments during office hours. Avoid important dates.
- 49. Containment Make the smallest change necessary to prove or disprove hypothesis.
- 50. Containment Make the smallest change necessary to prove or disprove hypothesis. Have a rollback plan. Stop the experiment right away if things start to go wrong.
- 51. Containment Don’t start in production. Can learn a lot by running experiments in staging.
- 52. by Russ Miles @russmiles source https://medium.com/russmiles/chaos-engineering-for-the-business-17b723f26361
- 53. New challenges with serverless
- 54. chaos monkey kills an EC2 instance latency monkey induces artificial delay in APIs chaos gorilla kills an AWS Availability Zone chaos kong kills an entire AWS region
- 56. Serverless challenges There are no servers that you can access and kill.
- 59. There are more inherent chaos and complexity in a serverless architecture.
- 60. Serverless challenges Smaller unit of deployment, but a lot more of them.
- 62. Serverless challenges Every function needs to be correctly configured and secured.
- 64. Serverless challenges A lot of managed, intermediate services. Each with its own set of failure modes.
- 65. Serverless challenges Unknown failure modes in the infrastructure we don’t control.
- 66. Serverless challenges Unknown failure modes in the infrastructure we don’t control. Often there’s little we can do when an outage occurs in the platform.
- 68. Common weaknesses Improperly tuned timeouts.
- 69. Common weaknesses Missing error handling.
- 71. Common weaknesses Missing regional failover.
- 72. Latency injection with serverless
- 73. STEP 1. Define “steady state” aka. what does normal, working condition looks like?
- 74. Defining steady state What metrics do you use?
- 75. Defining steady state What metrics do you use? p95/p99 latencies, error count, backlog size, yield*, harvest** * percentage of requests completed ** completeness of the returned response
- 76. Hypothesise steady state will continue in both control group & the experiment group ie. you should have a reasonable degree of confidence the system would handle the failure before you proceed with the experiment STEP 2.
- 78. Serverless considerations Consider the effect of cold starts. How does it affect your strategy for handling slow responses.
- 80. Request timeouts Strategy should: 1. Give requests the best chance to succeed
- 81. Request timeouts Strategy should: 1. Give requests the best chance to succeed 2. Do not allow slow response to timeout the caller function
- 82. Request timeouts Finding the right timeout value is tricky.
- 83. Request timeouts Finding the right timeout value is tricky. Too short : requests not given the best chance to succeed.
- 84. Request timeouts Finding the right timeout value is tricky. Too short : requests not given the best chance to succeed. Too long : risk timing out the calling function.
- 85. Request timeouts Finding the right timeout value is tricky. Too short : requests not given the best chance to succeed. Too long : risk timing out the calling function. Even more complicated when you have multiple integration points.
- 86. Approach 1: split invocation time equally (e.g. 3 requests, 6s function timeout = 2s timeout per request)
- 87. Approach 2: every request is given nearly all the invocation time (e.g. 3 requests, 6s function timeout = 5s timeout per request)
- 88. Request timeouts Proposal: set request timeouts dynamically based on invocation time left
- 89. Request timeouts
- 90. Set timeout based on remaining invocation time
- 91. Set timeout based on remaining invocation time
- 92. Recovery steps Log the timeout with as much context as possible. The API, timeout value, correlation IDs, request object, etc.
- 93. Recovery steps Log the timeout with as much context as possible. The API, timeout value, correlation IDs, request object, etc. Record custom metrics.
- 94. Recovery steps Log the timeout with as much context as possible. The API, timeout value, correlation IDs, request object, etc. Record custom metrics. Use fallbacks.
- 98. Recovery steps Be mindful when you sacrifice precision for availability. User experience is the king.
- 99. STEP 3. Inject realistic failures e.g. server crash, network error, HD malfunction, etc.
- 100. Where to inject latency?
- 101. hypothesis: Function has appropriate timeout on its HTTP communications and can degrade gracefully when these requests time out
- 102. Where to inject latency?
- 103. Where to inject latency? Should be applied to 3rd party services too. DynamoDB, Twillio, Auth0, …
- 104. Where to inject latency?
- 105. Where to inject latency? Be mindful of the blast radius of the experiment. The goal is not to break things.
- 106. http client public-api-a http client public-api-b internal-api Where to inject latency?
- 107. hypothesis: All functions have appropriate timeout on their HTTP communications to this internal API, and can degrade gracefully when requests are timed out
- 108. Where to inject latency?
- 109. Where to inject latency?
- 110. Where to inject latency? Large blast radius, can cause cascade failures unintentionally
- 112. development
- 114. Priming (psychology): Priming is a technique whereby exposure to one stimulus influences a response to a subsequent stimulus, without conscious guidance or intention. It is a technique in psychology used to train a person's memory both in positive and negative ways.
- 116. Use failure injection to programme your colleagues into thinking about failure modes early.
- 117. Where to inject latency? Make X% of all requests slow in the dev environment.
- 118. hypothesis: The client app has appropriate timeout on their HTTP communication with the server, and can degrade gracefully when requests are timed out
- 119. Where to inject latency?
- 120. Where to inject latency?
- 122. Where to inject latency?
- 123. STEP 4. Disprove hypothesis i.e. look for difference in steady state
- 124. How to inject latency?
- 125. How to inject latency? Static weavers (e.g. PostSharp, AspectJ). Dynamic proxies.
- 127. How to inject latency? Manually crafted wrapper libraries.
- 133. configured in SSM Parameter Store
- 135. no injected latency
- 139. factory wrapper function (think bluebird’s promisifyAll function)
- 145. Error injection with serverless
- 146. Common errors HTTP 5XX DynamoDB provisioned throughput exceeded Throttled Lambda invocations
- 147. hypothesis: Function has appropriate error handling on its HTTP communications and can degrade gracefully when downstream dependencies fail
- 148. Where to inject errors?
- 149. hypothesis: Function has appropriate error handling on DynamoDB operations and can degrade gracefully when DynamoDB throughputs are exceeded
- 150. Where to inject errors?
- 151. Where to inject errors? Induce Lambda throttling by temporarily setting reserved concurrency.
- 152. Recap
- 154. the only way to truly know your system’s resilience against failures is to test it through CONTROLLED experiments
- 156. the goal of chaos engineering is NOT to actually break production
- 157. CONTAINMENT should be front and centre of your thinking
- 159. STEP 1. Define “steady state” aka. what does normal, working condition looks like?
- 160. Hypothesise steady state will continue in both control group & the experiment group ie. you should have a reasonable degree of confidence the system would handle the failure before you proceed with the experiment STEP 2.
- 161. STEP 3. Inject realistic failures e.g. server crash, network error, HD malfunction, etc.
- 162. STEP 4. Disprove hypothesis i.e. look for difference in steady state
- 163. there are more inherent chaos and complexity in a serverless application
- 164. even without servers, you can still inject CONTROLLED failures at the application level
- 169. API Gateway and Kinesis Authentication & authorisation (IAM, Cognito) Testing Running & Debugging functions locally Log aggregation Monitoring & Alerting X-Ray Correlation IDs CI/CD Performance and Cost optimisation Error Handling Configuration management VPC Security Leading practices (API Gateway, Kinesis, Lambda) Canary deployments http://bit.ly/prod-ready-serverless get 40% off with: ytcui
- 170. @theburningmonk theburningmonk.com github.com/theburningmonk API Gateway and Kinesis Authentication & authorisation (IAM, Cognito) Testing Running & Debugging functions locally Log aggregation Monitoring & Alerting X-Ray Correlation IDs CI/CD Performance and Cost optimisation Error Handling Configuration management VPC Security Leading practices (API Gateway, Kinesis, Lambda) Canary deployments http://bit.ly/prod-ready-serverless get 40% off with: ytcui