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AWS Lambda at JUST EAT
- 1. AWS Lambda atJUST EAT ANDREW BROWN - Senior Platform Engineer
- 2. Overview Just Eat Early Adoption UseCases Serverless
- 3. • The world’sleading digital marketplace for takeaway food delivery • Founded in 2001 • Operate in 13 markets around the globe JUST EAT • Platform peak has processed 2,500 orders per minute • Thats a lot of Food!
- 4. TECHNOLOGY • Run hundredsof EC2 Instances at peak / dinner time • Scheduled Scaling of Resources - EC2, Dynamo Capacity • Heavily utilise CloudFormation • Just Eat Migrated to AWS 5 years ago - All In!
- 5. AWS - Setup •Multiple AWS Accounts • QA Daily Launch and Teardown • On average an instance less than 3 days old • • Approx 150 “features” - Each Feature has a Stack
- 6. What’s good aboutour Setup? Developers can concentrate on writing code • Packer, CodeDeploy, Consul, Cloudformation • Developers create package and deploy! • PaaS, IaaS
- 7. What’s good aboutour Setup? Consistency • Many accounts, environments, countries, features • All get the same AWS resources - e.g. Security Groups • Templated Cloudformations
- 8. AWS - Lambda •Re:Invent 2014 announcement • AWS Lambda runs your code in response to events • • “we could use that for x, y, and z!”
- 9. So Why UseLambda? • Lightweight • Cheaper • Less to manage • Quicker to Deploy
- 10. But Why ShouldJE Use Lambda? Let’s review One Feature • CloudFormation • EC2 Instances x 3 - Multi AZ • EBS Volumes • ELB Endpoint and Health Check • IAM Roles • DNS • Security Groups, Subnets, VPC • ASG settings, LaunchConfiguration ~ 1600 lines of JSON $0.246 x 3 x 24 x 365 (m4.large) $0.10 x 30 x 3 x 12 (gp2) $0.028 x 24 x 365 (classic) ~= $7k
- 11. So Why UseLambda? What does this Feature do? • Resets Delivery Time every morning • Publishes a SNS message about an order • Provision access for an instance • Tidy up resources
- 12. Early Lambdas ● NewTechnology! ● Multiple languages and frameworks ● Seen as additional parts of a feature ● Using the Console….
- 13. Early Lambdas Limitations /Problems ● Consistency (that’s Just Eat not AWS!) ● No VPC Support (Added Feb 2016) ● No Cron in Cloudformation ● Cloudformation Network Still Attached
- 14. Use Cases -PaaSBot • CloudFormation Stack per Environment • Windows EC2 Instance • Ran a bunch of Scheduled Tasks
- 15. Use Cases -PaaSBot Clean up EBS Volumes • Cron build in Teamcity - one per env • Scheduled Windows Task (one per account, assumed roles) • Lambda? Report Metrics • T2 Credit Balances • AWS Limits • Lambda?
- 16. Use Cases -PaaSBot Security Audit • Check Security Group rules • Check User access
- 17. Use Cases -PaaSLambda Lambdas • No Windows Instance(s) • Micro-Scheduled Tasks • Easier to update • Better visibility
- 18. Use Cases -Instance Access • Recently started using HashiCorp Consul and Vault • Concerns : “What can my instance access?” • Consul ACLS and Vault Tokens - limit what key/values you can access • ACLs Initially provisioned via Deployment Tool
- 19. Use Cases -Instance Launch • Lambdas Created with Consul and Vault Cloudformations - nodejs • ASG Event -> CloudWatch Events -> Trigger Lambda • Provisions ACL and AppId login • Removes Access when Instance terminated
- 20. Use Cases -Instance Launch Launch Stack i-12345 i-12345 i-12345 ASG CloudWatch Event { “acl” : a1a1a1-b2b2b2 } { “token” : secrettoken }
- 21. Use Cases -Instance Terminate Delete Stack / Scale Down i-12345 i-12345 i-12345 ASG CloudWatch Event
- 22. Different Approach • Startingto create Lambda Features • Needed a consistent approach • Recently Implemented Serverless
- 23. Serverless • Still in“Beta”
- 24. Serverless Good Points • BringsBack Consistency • Ease to deploy • Defined Dependencies • Being Quickly Adopted • Track signal strength • Calculate cost • Check capacity • Start Ad-hoc backup / Prune Log files
- 25. Serverless Not so GoodPoints • Currently each Feature includes their AWS resources - previously templated • Code repeated • Monitoring & Logging Immature
- 26. Lessons Learnt &Future Plans • Difficult to integrate into our Platform - Versatility • Still a few Bugs - • Serverless - Based on Initial Uptake • AWS Lambda & API Gateway • Will it replace our APIs? - Maybe
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