Amazon Kinesis Streams enables you to build custom applications that process or analyze streaming data for specialized needs. You can continuously add various types of data such as clickstreams, application logs, and social media to an Amazon Kinesis stream from hundreds of thousands of sources. Within seconds, the data will be available for your Amazon Kinesis Applications to read and process from the stream.
Q: What does Amazon Kinesis Streams manage on my behalf?
Amazon Kinesis Streams manages the infrastructure, storage, networking, and configuration needed to stream your data at the level of your data throughput. You do not have to worry about provisioning, deployment, ongoing-maintenance of hardware, software, or other services for your data streams. In addition, Amazon Kinesis Streams synchronously replicates data across three facilities in an AWS Region, providing high availability and data durability.
Q: What can I do with Amazon Kinesis Streams?
Amazon Kinesis Streams is useful for rapidly moving data off data producers and then continuously processing the data, be it to transform the data before emitting to a data store, run real-time metrics and analytics, or derive more complex data streams for further processing. The following are typical scenarios for using Amazon Kinesis Streams:
- Accelerated log and data feed intake: Instead of waiting to batch up the data, you can have your data producers push data to an Amazon Kinesis stream as soon as the data is produced, preventing data loss in case of data producer failures. For example, system and application logs can be continuously added to a stream and be available for processing within seconds.
- Real-time metrics and reporting: You can extract metrics and generate reports from Amazon Kinesis stream data in real-time. For example, your Amazon Kinesis Application can work on metrics and reporting for system and application logs as the data is streaming in, rather than wait to receive data batches.
- Real-time data analytics: With Amazon Kinesis Streams, you can run real-time streaming data analytics. For example, you can add clickstreams to your Amazon Kinesis stream and have your Amazon Kinesis Application run analytics in real-time, enabling you to gain insights out of your data at a scale of minutes instead of hours or days.
- Complex stream processing: You can create Directed Acyclic Graphs (DAGs) of Amazon Kinesis Applications and data streams. In this scenario, one or more Amazon Kinesis Applications can add data to another Amazon Kinesis stream for further processing, enabling successive stages of stream processing.
Q: How do I use Amazon Kinesis Streams?
After you sign up for Amazon Web Services, you can start using Amazon Kinesis Streams by:
- Creating an Amazon Kinesis stream through either Amazon Kinesis Management Console or CreateStream operation.
- Configuring your data producers to continuously add data to your stream.
- Building your Amazon Kinesis Applications to read and process data from your stream, using either Amazon Kinesis API or Amazon Kinesis Client Library (KCL).
Q: What are the limits of Amazon Kinesis Streams?
The throughput of an Amazon Kinesis stream is designed to scale without limits via increasing the number of shards within a stream. However, there are certain limits you should keep in mind while using Amazon Kinesis Streams:
- By default, Records of a stream are accessible for up to 24 hours from the time they are added to the stream. You can raise this limit to up to 7 days by enabling extended data retention.
- The maximum size of a data blob (the data payload before Base64-encoding) within one record is 1 megabyte (MB).
- Each shard can support up to 1000 PUT records per second.
For more information about other API level limits, see Amazon Kinesis Streams Limits.
Q: How does Amazon Kinesis Streams differ from Amazon SQS?
Amazon Kinesis Streams enables real-time processing of streaming big data. It provides ordering of records, as well as the ability to read and/or replay records in the same order to multiple Amazon Kinesis Applications. The Amazon Kinesis Client Library (KCL) delivers all records for a given partition key to the same record processor, making it easier to build multiple applications reading from the same Amazon Kinesis stream (for example, to perform counting, aggregation, and filtering).
Amazon Simple Queue Service (Amazon SQS) offers a reliable, highly scalable hosted queue for storing messages as they travel between computers. Amazon SQS lets you easily move data between distributed application components and helps you build applications in which messages are processed independently (with message-level ack/fail semantics), such as automated workflows.
Q: When should I use Amazon Kinesis Streams, and when should I use Amazon SQS?
We recommend Amazon Kinesis Streams for use cases with requirements that are similar to the following:
- Routing related records to the same record processor (as in streaming MapReduce). For example, counting and aggregation are simpler when all records for a given key are routed to the same record processor.
- Ordering of records. For example, you want to transfer log data from the application host to the processing/archival host while maintaining the order of log statements.
- Ability for multiple applications to consume the same stream concurrently. For example, you have one application that updates a real-time dashboard and another that archives data to Amazon Redshift. You want both applications to consume data from the same stream concurrently and independently.
- Ability to consume records in the same order a few hours later. For example, you have a billing application and an audit application that runs a few hours behind the billing application. Because Amazon Kinesis Streams stores data for up to 7 days, you can run the audit application up to 7 days behind the billing application.
We recommend Amazon SQS for use cases with requirements that are similar to the following:
- Messaging semantics (such as message-level ack/fail) and visibility timeout. For example, you have a queue of work items and want to track the successful completion of each item independently. Amazon SQS tracks the ack/fail, so the application does not have to maintain a persistent checkpoint/cursor. Amazon SQS will delete acked messages and redeliver failed messages after a configured visibility timeout.
- Individual message delay. For example, you have a job queue and need to schedule individual jobs with a delay. With Amazon SQS, you can configure individual messages to have a delay of up to 15 minutes.
- Dynamically increasing concurrency/throughput at read time. For example, you have a work queue and want to add more readers until the backlog is cleared. With Amazon Kinesis Streams, you can scale up to a sufficient number of shards (note, however, that you'll need to provision enough shards ahead of time).
- Leveraging Amazon SQS’s ability to scale transparently. For example, you buffer requests and the load changes as a result of occasional load spikes or the natural growth of your business. Because each buffered request can be processed independently, Amazon SQS can scale transparently to handle the load without any provisioning instructions from you.
Shard is the base throughput unit of an Amazon Kinesis stream. One shard provides a capacity of 1MB/sec data input and 2MB/sec data output. One shard can support up to 1000 PUT records per second. You will specify the number of shards needed when you create a stream. For example, you can create a stream with two shards. This stream has a throughput of 2MB/sec data input and 4MB/sec data output, and allows up to 2000 PUT records per second. You can monitor shard-level metrics in Amazon Kinesis Streams and add or remove shards from your stream dynamically as your data throughput changes by resharding the stream.
A record is the unit of data stored in an Amazon Kinesis stream. A record is composed of a sequence number, partition key, and data blob. Data blob is the data of interest your data producer adds to a stream. The maximum size of a data blob (the data payload before Base64-encoding) is 1 megabyte (MB).
Partition key is used to segregate and route records to different shards of a stream. A partition key is specified by your data producer while adding data to an Amazon Kinesis stream. For example, assuming you have a stream with two shards (shard 1 and shard 2). You can configure your data producer to use two partition keys (key A and key B) so that all records with key A are added to shard 1 and all records with key B are added to shard 2.
A sequence number is a unique identifier for each record. Sequence number is assigned by Amazon Kinesis when a data producer calls PutRecord or PutRecords operation to add data to an Amazon Kinesis stream. Sequence numbers for the same partition key generally increase over time; the longer the time period between PutRecord or PutRecords requests, the larger the sequence numbers become.
Q: How do I decide the throughput of my Amazon Kinesis stream?
The throughput of an Amazon Kinesis stream is determined by the number of shards within the stream. Follow the steps below to estimate the initial number of shards your stream needs. Note that you can dynamically adjust the number of shards within your stream via resharding.
- Estimate the average size of the record written to the stream in kilobytes (KB), rounded up to the nearest 1 KB. (average_data_size_in_KB)
- Estimate the number of records written to the stream per second. (number_of_records_per_second)
- Decide the number of Amazon Kinesis Applications consuming data concurrently and independently from the stream. (number_of_consumers)
- Calculate the incoming write bandwidth in KB (incoming_write_bandwidth_in_KB), which is equal to the average_data_size_in_KB multiplied by the number_of_records_per_seconds.
- Calculate the outgoing read bandwidth in KB (outgoing_read_bandwidth_in_KB), which is equal to the incoming_write_bandwidth_in_KB multiplied by the number_of_consumers.
You can then calculate the initial number of shards (number_of_shards) your stream needs using the following formula:
number_of_shards = max (incoming_write_bandwidth_in_KB/1000, outgoing_read_bandwidth_in_KB/2000)
Q: What is the minimum throughput I can request for my Amazon Kinesis stream?
The throughput of an Amazon Kinesis stream scales by unit of shard. One single shard is the smallest throughput of a stream, which provides 1MB/sec data input and 2MB/sec data output.
Q: What is the maximum throughput I can request for my Amazon Kinesis stream?
The throughput of an Amazon Kinesis stream is designed to scale without limits. By default, each account can provision 10 shards per region. You can use the Amazon Kinesis Streams Limits form to request more than 10 shards within a single region.
Q: How can record size affect the throughput of my Amazon Kinesis stream?
A shard provides 1MB/sec data input rate and supports up to 1000 PUT records per sec. Therefore, if the record size is less than 1KB, the actual data input rate of a shard will be less than 1MB/sec, limited by the maximum number of PUT records per second.
Q: What is the difference between PutRecord and PutRecords?
PutRecord operation allows a single data record within an API call and PutRecords operation allows multiple data records within an API call. For more information about PutRecord and PutRecords operations, see PutRecord and PutRecords.
Q: What is Amazon Kinesis Producer Library (KPL)?
Amazon Kinesis Producer Library (KPL) is an easy to use and highly configurable library that helps you put data into an Amazon Kinesis stream. KPL presents a simple, asynchronous, and reliable interface that enables you to quickly achieve high producer throughput with minimal client resources.
Q: What programming languages or platforms can I use to access Amazon Kinesis API?
Amazon Kinesis API is available in Amazon Web Services SDKs. For a list of programming languages or platforms for Amazon Web Services SDKs, see Tools for Amazon Web Services.
Q: What programming language is Amazon Kinesis Producer Library (KPL) available in?
Amazon Kinesis Producer Library (KPL)'s core is built with C++ module and can be compiled to work on any platform with a recent C++ compiler. The library is currently available in a Java interface. We are looking to add support for other programming languages.
Q: What is Amazon Kinesis Agent?
Amazon Kinesis Agent is a pre-built Java application that offers an easy way to collect and send data to your Amazon Kinesis stream. You can install the agent on Linux-based server environments such as web servers, log servers, and database servers. The agent monitors certain files and continuously sends data to your stream. For more information, see Writing with Agents.
Q: What platforms do Amazon Kinesis Agent support?
Amazon Kinesis Agent currently supports Amazon Linux or Red Hat Enterprise Linux.
Q: Where do I get Amazon Kinesis Agent?
You can download and install Amazon Kinesis Agent using the following command and link:
On Amazon Linux: sudo yum install –y aws-kinesis-agent
On Red Hat Enterprise Linux: sudo yum install –y https://s3.amazonaws.com/streaming-data-agent/aws-kinesis-agent-latest.amzn1.noarch.rpm
From GitHub: awlabs/amazon-kinesis-agent
Q: How do I use Amazon Kinesis Agent?
After installing Amazon Kinesis Agent on your servers, you configure it to monitor certain files on the disk and then continuously send new data to your Amazon Kinesis stream. For more information, see Writing with Agents.
Q: What happens if the capacity limits of an Amazon Kinesis stream are exceeded while the data producer adds data to the stream?
The capacity limits of an Amazon Kinesis stream are defined by the number of shards within the stream. The limits can be exceeded by either data throughput or the number of PUT records. While the capacity limits are exceeded, the put data call will be rejected with a ProvisionedThroughputExceeded exception. If this is due to a temporary rise of the stream’s input data rate, retry by the data producer will eventually lead to completion of the requests. If this is due to a sustained rise of the stream’s input data rate, you should increase the number of shards within your stream to provide enough capacity for the put data calls to consistently succeed. In both cases, Amazon CloudWatch metrics allow you to learn about the change of the stream’s input data rate and the occurrence of ProvisionedThroughputExceeded exceptions.
Q: What data is counted against the data throughput of an Amazon Kinesis stream during a PutRecord or PutRecords call?
Your data blob, partition key, and stream name are required parameters of a PutRecord or PutRecords call. The size of your data blob (before Base64 encoding) and partition key will be counted against the data throughput of your Amazon Kinesis stream, which is determined by the number of shards within the stream.
An Amazon Kinesis Application is a data consumer that reads and processes data from an Amazon Kinesis stream. You can build your applications using either Amazon Kinesis API or Amazon Kinesis Client Library (KCL).
Amazon Kinesis Client Library (KCL) for Java | Python | Ruby | Node.js | .NET is a pre-built library that helps you easily build Amazon Kinesis Applications for reading and processing data from an Amazon Kinesis stream. KCL handles complex issues such as adapting to changes in stream volume, load-balancing streaming data, coordinating distributed services, and processing data with fault-tolerance. KCL enables you to focus on business logic while building applications.
Q: What is Amazon Kinesis Connector Library?
Amazon Kinesis Connector Library is a pre-built library that helps you easily integrate Amazon Kinesis Streams with other AWS services and third-party tools. Amazon Kinesis Client Library (KCL) for Java | Python | Ruby | Node.js | .NET is required for using Amazon Kinesis Connector Library. The current version of this library provides connectors to Amazon DynamoDB, Amazon Redshift, Amazon S3, and Elasticsearch. The library also includes sample connectors of each type, plus Apache Ant build files for running the samples.
Q: What is Amazon Kinesis Storm Spout?
Amazon Kinesis Storm Spout is a pre-built library that helps you easily integrate Amazon Kinesis Streams with Apache Storm. The current version of Amazon Kinesis Storm Spout fetches data from Amazon Kinesis stream and emits it as tuples. You will add the spout to your Storm topology to leverage Amazon Kinesis Streams as a reliable, scalable, stream capture, storage, and replay service.
Q: What programming language are Amazon Kinesis Client Library (KCL), Amazon Kinesis Connector Library, and Amazon Kinesis Storm Spout available in?
Amazon Kinesis Client Library (KCL) is currently available in Java, Python, Ruby, Node.js, and .NET. Amazon Kinesis Connector Library and Amazon Kinesis Storm Spout are currently available in Java. We are looking to add support for other programming languages.
Q: Do I have to use Amazon Kinesis Client Library (KCL) for my Amazon Kinesis Application?
No, you can also use Amazon Kinesis API to build your Amazon Kinesis Application. However, we recommend using Amazon Kinesis Client Library (KCL) for Java | Python | Ruby | Node.js | .NET if applicable because it performs heavy-lifting tasks associated with distributed stream processing, making it more productive to develop applications.
Q: How does Amazon Kinesis Client Library (KCL) interact with an Amazon Kinesis Application?
Amazon Kinesis Client Library (KCL) for Java | Python | Ruby | Node.js | .NET acts as an intermediary between Amazon Kinesis Streams and your Amazon Kinesis Application. KCL uses the IRecordProcessor interface to communicate with your application. Your application implements this interface, and KCL calls into your application code using the methods in this interface.
For more information about building application with KCL, see Developing Consumer Applications for Amazon Kinesis Using the Amazon Kinesis Client Library.
An Amazon Kinesis Application can have multiple application instances and a worker is the processing unit that maps to each application instance. A record processor is the processing unit that processes data from a shard of an Amazon Kinesis stream. One worker maps to one or more record processors. One record processor maps to one shard and processes records from that shard.
At startup, an application calls into Amazon Kinesis Client Library (KCL) for Java | Python | Ruby | Node.js | .NET to instantiate a worker. This call provides KCL with configuration information for the application, such as the stream name and AWS credentials. This call also passes a reference to an IRecordProcessorFactory implementation. KCL uses this factory to create new record processors as needed to process data from the stream. KCL communicates with these record processors using the IRecordProcessor interface.
Q: How does Amazon Kinesis Client Library (KCL) keep tracking data records being processed by an Amazon Kinesis Application?
Amazon Kinesis Client Library (KCL) for Java | Python | Ruby | Node.js | .NET automatically creates an Amazon DynamoDB table for each Amazon Kinesis Application to track and maintain state information such as resharding events and sequence number checkpoints. The DynamoDB table shares the same name with the application so that you need to make sure your application name doesn’t conflict with any existing DynamoDB tables under the same account within the same region.
All workers associated with the same application name are assumed to be working together on the same Amazon Kinesis stream. If you run an additional instance of the same application code, but with a different application name, KCL treats the second instance as an entirely separate application also operating on the same stream.
Please note that your account will be charged for the costs associated with the Amazon DynamoDB table in addition to the costs associated with Amazon Kinesis Streams.
For more information about how KCL tracks application state, see Tracking Amazon Kinesis Application state.
Q: How can I automatically scale up the processing capacity of my Amazon Kinesis Application using Amazon Kinesis Client Library (KCL)?
You can create multiple instances of your Amazon Kinesis Application and have these application instances run across a set of Amazon EC2 instances that are part of an Auto Scaling group. While the processing demand increases, an Amazon EC2 instance running your application instance will be automatically instantiated. Amazon Kinesis Client Library (KCL) for Java | Python | Ruby | Node.js | .NET will generate a worker for this new instance and automatically move record processors from overloaded existing instances to this new instance.
Q: Why does GetRecords call return empty result while there is data within my Amazon Kinesis stream?
One possible reason is that there is no record at the position specified by the current shard iterator. This could happen even if you are using TRIM_HORIZON as shard iterator type. An Amazon Kinesis stream represents a continuous stream of data. You should call GetRecords operation in a loop and the record will be returned when the shard iterator advances to the position where the record is stored.
Q: What is ApproximateArrivalTimestamp retruned in GetRecords operation?
Each record includes a value called ApproximateArrivalTimestamp. It is set when the record is successfully received and stored by Amazon Kinesis. This timestamp has millisecond precision and there are no guarantees about the timestamp accuracy. For example, records in a shard or across a stream might have timestamps that are out of order.
Q: What happens if the capacity limits of an Amazon Kinesis stream are exceeded while Amazon Kinesis Application reads data from the stream?
The capacity limits of an Amazon Kinesis stream are defined by the number of shards within the stream. The limits can be exceeded by either data throughput or the number of read data calls. While the capacity limits are exceeded, the read data call will be rejected with a ProvisionedThroughputExceeded exception. If this is due to a temporary rise of the stream’s output data rate, retry by the Amazon Kinesis Application will eventually lead to completions of the requests. If this is due to a sustained rise of the stream’s output data rate, you should increase the number of shards within your stream to provide enough capacity for the read data calls to consistently succeed. In both cases, Amazon CloudWatch metrics allow you to learn about the change of the stream’s output data rate and the occurrence of ProvisionedThroughputExceeded exceptions.
You can change the throughput of an Amazon Kinesis stream by adjusting the number of shards within the stream (resharding). There are two types of resharding operations: shard split and shard merge. In a shard split, a single shard is divided into two shards, which increases the throughput of the stream. In a shard merge, two shards are merged into a single shard, which decreases the throughput of the stream. For more information about Amazon Kinesis Streams resharding, see Resharding a Stream.
Q: How often can I and how long does it take to change the throughput of my Amazon Kinesis stream?
A resharding operation such as shard split or shard merge takes a few seconds. You can only perform one resharding operation at a time. Therefore, for an Amazon Kinesis stream with only one shard, it takes a few seconds to double the throughput by splitting one shard. For a stream with 1000 shards, it takes 30K seconds (8.3 hours) to double the throughput by splitting 1000 shards. We recommend increasing the throughput of your stream ahead of the time when extra throughput is needed.
Q: Does Amazon Kinesis Streams remain available when I change the throughput of my Amazon Kinesis stream via resharding?
Yes. You can continue adding data to and reading data from your Amazon Kinesis stream while resharding is performing to change the throughput of the stream.
Q: How do I change the data retention period of my Amazon Kinesis stream?
Amazon Kinesis stores your data for up to 24 hours by default. You can raise data retention period to up to 7 days by enabling extended data retention.
For more information about changing data retention period, see Changing Data Retention Period.
Q: How do I monitor the operations and performance of my Amazon Kinesis stream?
Amazon Kinesis Streams Management Console displays key operational and performance metrics such as throughput of data input and output of your Amazon Kinesis streams. Amazon Kinesis Streams also integrates with Amazon CloudWatch so that you can collect, view, and analyze CloudWatch metrics for your streams and shards within those streams. For more information about Amazon Kinesis Streams metrics, see Monitoring Amazon Kinesis Streams with Amazon CloudWatch.
Please note that all stream-level metrics are free of charge. All enabled shard-level metrics are charged at Amazon CloudWatch Pricing.
Q: How do I manage and control access to my Amazon Kinesis stream?
Amazon Kinesis Streams integrates with AWS Identity and Access Management (IAM), a service that enables you to securely control access to your AWS services and resources for your users. For example, you can create a policy that only allows a specific user or group to add data to your Amazon Kinesis stream. For more information about access management and control of your stream, see Controlling Access to Amazon Kinesis Streams Resources using IAM.
Q: How do I log API calls made to my Amazon Kinesis stream for security analysis and operational troubleshooting?
Amazon Kinesis integrates with Amazon CloudTrail, a service that records AWS API calls for your account and delivers log files to you. For more information about API call logging and a list of supported Amazon Kinesis API operations, see Logging Amazon Kinesis API calls Using Amazon CloudTrail.
Q: How do I effectively manage my Amazon Kinesis streams and the costs associated with these streams?
Amazon Kinesis Streams allows you to tag your Amazon Kinesis streams for easier resource and cost management. A tag is a user-defined label expressed as a key-value pair that helps organize AWS resources. For example, you can tag your streams by cost centers so that you can categorize and track your Amazon Kinesis Streams costs based on cost centers. For more information about Amazon Kinesis Streams tagging, see Tagging Your Amazon Kinesis Streams.
No. Amazon Kinesis Streams is not currently available in AWS Free Tier. AWS Free Tier is a program that offers free trial for a group of AWS services. For more details about AWS Free Tier, see AWS Free Tier.
Q: How much does Amazon Kinesis Streams cost?
Amazon Kinesis Streams uses simple pay as you go pricing. There is neither upfront cost nor minimum fees and you only pay for the resources you use. The costs of Amazon Kinesis Streams has two core dimensions and one optional dimension:
- Hourly Shard cost determined by the number of shards within your Amazon Kinesis stream.
- PUT Payload Unit cost determined by the number of 25KB payload units that your data producers add to your stream.
- Optional Extended Data Retention cost determined by number of shard hours incurred by your stream.
For more information about Amazon Kinesis Streams costs, see Amazon Kinesis Streams Pricing.
Q: Does my PUT Payload Unit cost change by using PutRecords operation instead of PutRecord operation?
PUT Payload Unit charge is calculated based on the number of 25KB payload units added to your Amazon Kinesis stream. PUT Payload Unit cost is consistent when using PutRecords operation or PutRecord operation.
Q: Am I charged for shards in "CLOSED" state?
A shard could be in "CLOSED" state after resharding. You will not be charged for shards in "CLOSED" state.
Q: Other than Amazon Kinesis Streams costs, are there any other costs that might incur to my Amazon Kinesis Streams usage?
Amazon Kinesis Client Library (KCL) uses Amazon DynamoDB table to track state information of record processing. If you use KCL for you Amazon Kinesis Applications, you will be charged for Amazon DynamoDB resources in addition to Amazon Kinesis Streams costs.
Please note that the above are three common but not exhaustive cases.