AWS Kinesis

• Kinesis is a managed alternative to Apache Kafka
• It is a big data stream tool, which allows to stream application logs, metrics, IoT data, click streams, etc.
• Compatible with many streaming frameworks (Spark, NiFi, etc.)
• Data is automatically replicated to 3 AZ
• Kineses offers 3 types of products:
  • Kinesis Streams: low latency streaming ingest at scale
  • Kinesis Analytics: perform real-time analytics on streams using SQL
  • Kinesis Firehose: load streams into S3, Redshift, ElasticSearch

Kinesis Streams Overview

• Streams are divided in ordered Shards/Partitions
• For higher throughput we can increase the size of the shards
• Data retention is 1 day by default, can go up to 7 days
• Kinesis Streams provides the ability to reprocess/replay the data
• Multiple applications can consume the same stream, this enables real-time processing with scale of throughput
• Kinesis is not a database, once the data is inserted, it can not be deleted

Kinesis Stream Shards

• One stream is made of many different shards
• 1MB/s or 1000 messages at write PER SHARD
• 2MB/s read PER SHARD
• Billing is done per shard provisioned, we can have a many shards as we want as long as we accept the cost
• Ability to batch the messages per calls
• The number of shards can evolve over time (reshard/merge)
• Records are ordered per shard!

Kinesis Streams API - Put Records

• Data must be sent form the PutRecords API to a partition key
• Data with the same key goes to the same partition (helps with ordering for a specific key)
• Messages sent get a sequence number
• Partition key must be highly distributed in order to avoid hot partitions
• In order to reduce costs, we can use batching with PutRecords API
• It the limits are reached, we get a ProvisionedThroughputException

Exceptions

• ProvisionedThroughputException Exceptions:
  • Happens when the data value exceeds the limit exposed by the shard
  • In order to avoid the, we have to make sure we don’t have hot partitions
  • Solutions:
    • Retry with back-off
    • Increase shards (scaling)
    • Ensure the partition key is good

Consumers

• Consumers can use CLI or SDK, or the Kinesis Client Library (in Java, Node, Python, Ruby, .Net)
• Kinesis Client Library (KCL) uses DynamoDB to checkpoint offsets
• KCL uses DynamoDB to track other workers and share work amongst shards

Security

• Control access / authorization using IAM policies
• Encryption in flight using HTTPS endpoints
• Encryption at rest using KMS
• Possibility to encrypt/decrypt data client side
• VPC Endpoints available for Kinesis to be access within VPCs

Kinesis Data Firehose

• Fully managed service, no administration required, provides automatic scaling, it is basically serverless
• Used for load data into Redshift, S3, ElasticSearch and Splunk
• It is Near Real Time: 60 seconds latency minimum for non full batches or minimum 32 MB of data at a time
• Supports many data formats, conversions, transformation and compression
• Pay for the amount of data going through Firehose

Kinesis Data Streams vs Firehose

• Streams:
  • Requires to write custom code (producer/consumer)
  • Real time (~200 ms)
  • Must manage scaling (shard splitting / merging)
  • Can store data into stream, data can be stored from 1 to 7 days
  • Data can be read by multiple consumers
• Firehose:
  • Fully managed, sends data to S3, Redshift, Splunk, ElasticSearch
  • Serverless, data transformation can be done with Lambda
  • Near real time
  • Scales automatically
  • It provides no data storage

Kinesis Data Analytics

• Can take data from Kinesis Data Streams and Kinesis Firehose and perform some queries on it
• It can perform real-time analytics using SQL
• Kinesis Data Analytics properties:
  • Automatically scales
  • Managed: no servers to provision
  • Continuous: analytics are done in real time
• Pricing: pay per consumption rate
• It can create streams out of real-time queries

Data Ordering with Kinesis

• Data with the same partition key goes to the same shard
• Data is ordered per shard

SQS vs SNS vs Kinesis

• SQS:
  • Consumers pull data
  • Data is deleted after being consumed
  • Can have many consumers as we want
  • No need to provision throughput
  • No ordering guarantee in case of standard queues
  • Capability to delay individual messages
• SNS:
  • Pub/Sub: publish data to many subscribers
  • We can have up to 10 million subscribers per topic
  • Data is not persisted (it is lost if not delivered)
  • Up to 10k topics per account
  • No need to provision throughput
  • Integrates with SQS for fan-out architecture
• Kinesis Data Streams:
  • Consumers “pull data”
  • We can have as many consumers as we want
  • Possibility to replay data
  • Recommended for real-time big data analytics and ETL
  • Ordering happens at the shard level
  • Data expires after X days
  • Must provision throughput