问题
We are planning to use REST API calls to ingest data from an endpoint and store the data to HDFS. The REST calls are done in a periodic fashion (daily or maybe hourly).
I've already done Twitter ingestion using Flume, but I don't think using Flume would suit my current use-case because I am not using a continuous data firehose like this one in Twitter, but rather discrete regular time-bound invocations.
The idea I have right now, is to use custom Java that takes care of REST API calls and saves to HDFS, and then use Oozie coordinator on that Java jar.
I would like to hear suggestions / alternatives (if there's easier than what I'm thinking right now) about design and which Hadoop-based component(s) to use for this use-case. If you feel I can stick to Flume, then kindly give me also an idea how to do this.
回答1:
As stated in the Apache Flume web:
Apache Flume is a distributed, reliable, and available system for efficiently collecting, aggregating and moving large amounts of log data from many different sources to a centralized data store.
As you can see, among the features attributed to Flume is the gathering of data. "Pushing-like or emitting-like" data sources are easy to integrate thanks to HttpSource, AvroSurce, ThriftSource, etc. In your case, where the data must be let's say "actively pulled" from a http-based service, the integration is not so obvious, but can be done. For instance, by using the ExecSource, which runs a script getting the data and pushing it to the Flume agent.
If you use a proprietary code in charge of pulling the data and writting it into HDFS, such a design will be OK, but you will be missing some interesting built-in Flume characteristics (that probably you will have to implement by yourself):
- Reliability. Flume has mechanisms to ensure the data is really persisted in the final storage, retrying until is is effectively written. This is achieved through the usage of an internal channel buffering data both at the input (ingesting peaks of loads) and the output (retaining data until it is effecively persisted) and the transaction concept.
- Performance. The usage of transactions and the possibility to configure multiple parallel sinks (data processors) will your deployment able to deal with really large amounts of data generated per second.
- Usability. By using Flume you don't need to deal with the storage details (e.g. HDFS API). Even, if some day you decide to change the final storage you only have to reconfigure the Flume agent for using the new related sink.
来源：https://stackoverflow.com/questions/33645260/suggested-hadoop-based-design-component-for-ingestion-of-periodic-rest-api-cal