AWS Lambda and Cassandra

Transcription

1 Paris AWS User Group 5th Sep 2018 AWS Lambda and Cassandra Lyuben Todorov Director of Consulting, EMEA

2 PARIS AWS User Group Les AWS User Group permettent aux utilisateurs d AWS de communiquer et échanger pour répondre à des questions, partager des idées et tout savoir sur les nouveaux services et les bonnes pratiques utilisateurs

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4 Me Lyuben Todorov Consulting Director Instaclustr EMEA Univ. of Dundee Distributed Programming / OSS Social Media: /in/lyubent

5 Talk Overview Cassandra + λ Scale POC λ and C* (Cassandra) introduction Why use λ and Instaclustr s managed service High Level Setup of λ and C* in Instaclustr Technical Challenges of using λ Lessons Learned

6 What is λ Serverless Pay for execution time (1M requests free) (400k GBsec free) Auto-scale Always Available Server App Operation Operation Database Operation Operation

7 What is λ Serverless (no need to share) Pay for execution time (1M requests free) (400k GBsec free) Auto-scale Always Available λ Operation λ Operation

8 What is λ User Event Serverless (no need to share) Pay for execution time (1M requests free) (400k GBsec free) Auto-scale Always Available Container Creation λ Operation λ Operation Container Teardown

9 λ Use-cases Peeking Applications Event driven applications Short Code Execution Times

10 What is C* Available Highly Available Distributed Database No SPOF (p2p architecture) Open Source Tunable Consistency Partition Tolerant Consistent

11 C* Client Relevant to lambda: Gossip used by client to discover nodes create λ per DC and use DC Aware Client Query with LOCAL consistencies Be careful with client timestamps (due to cold start)

12 Instaclustr Hosted Service Simple Auto scaling service 24/7 Support Access to Analytics Dashboard for Monitoring Security Plugins

13 How to set up λ Connect λ to Backend Deploy and test web app Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

14 Create VPC Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

15 VPC Subnet Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

16 Add Some Instant Awesome Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

17 Pick Your Cloud Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

18 Choose Node Capacity & Type Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

19 Scalable backend Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

20 Peering λ and C* s VPCs Lambda s VPC needs to be connected with Instaclustr s Cassandra VPC via Instaclustr console: Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

21 Route Tables Add rule for the API Gateway Add rule for Instaclustr VPC Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

22 Create λ in AWS Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

23 Deploy λ Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

24 Deploy λ Create λ VPC Create subnet for VPC Provision C* Cluster VPC Peering Request C* to λ Update Route Table Create & Deploy λ

25 Architecture

26 The App Allows to process web requests POST used for inserting an event GET used for fetching an event Cassandra Table (Model): CREATE TABLE event ( id uuid, source text, type text, recorded timestamp, PRIMARY KEY(id) )

27 The App - API Gateway Two resources added (POST and GET)

28 The App - API Gateway POST /event/ writes an event to C* session.execute("insert INTO ic.event (id, source, type, recorded)" + "VALUES (now(), ' ', 'Auth', totimestamp(now())"); GET /event/{id} retrieves an event from C* by id. session.execute("select * FROM ic.event");

29 The App - Code Java Application Request processed as stream Output as JSON public void handler(inputstream inputstream, OutputStream outputstream, Context context) { // IMPL. // Pass request to either GET or POST depending on context. }

30 Challenges Application Scalability λ Warmup Time Reducing Memory Usage Connection Pooling Dependency Management Execution Environment Limits

31 Scaling Requests Load balancer can distribute requests Adds Complexity What if a backend changes

32 Scaling Requests with λ Lambda scales app automatically Re-deploy only 1 thing on app update

33 Scaling Requests with λ Configure concurrent execution Write good app code!

34 Function Warmup Time Cold start is when λ has to initialise resources in order to execute a λ Container / NIC / other resources. Containers torn-down after 15 min of inactivity = cold start after λ Function avoids cold-start if constantly running

35 Function Warmup Time 12 Avg. Request Response Time (sec) Parallel Requests (hundreds) time (min) 5 6 7

36 Function Warmup Time Cheat Ping the λ every 5-10 mins Create a Rule in AWS as an Event and schedule it to run every 10 min. Monitor container changes

37 Reduce Memory Usage 512 MB by default Way too much for a simple C* client CPU is proportional to memory allocated to app

38 Connection Pool Management Creating connections is expensive Connection pooling allows reuse λ is stateless and asynchronous in nature

39 Connection Pool Management Store session state outside of handler function s scope Variables outside of handler remain initialised across λ calls // Keep client wrapper outside of handlereqest function // will keep client initialised throughout λ execution private CassandraClient client = new CassandraClient(); public String handlerequest(map<string,object> input, Context context) { return "C* Version: " + client.getversion(); }}

40 Dependency Management (Java ftw) Lean dependencies Smaller App Faster Deployment Less Downtime No Logger Jar Size 7.3 MB pom.xml <dependency> <groupid>io.symphonia</groupid> <artifactid>lambda-logging</artifactid> <version>1.0.1</version> </dependency> Symphonia Jar Size 8.1 MB Log4J Jar Size 8.6 MB

41 Execution Environment Limits Limited to 512 MB of disk 3008 MB Memory Limit Max timeout 5 mins. Max response payload 6MB Event payload 128 KB Per λ invocation

42 POC Benchmark Create client to send out periodically increasing requests Run for 7 min 30 sec Review Cassandra latency metric

43 Outcome Latency 75percentile (μs) Requests Time (sec)

44 Q&λ