Metis: Constructing Airbnb’s Subsequent Era Information Administration Platform | by Xiaobin Zheng | The Airbnb Tech Weblog | Jun, 2023

Xiaobin Zheng
The Airbnb Tech Blog

How Airbnb developed our knowledge catalog right into a platform for managing and governing our knowledge warehouse at scale.

By: Erik Ritter, Jiaxin Ye, Sylvia Tomiyama, Woody Zhou, Xiaobin Zheng, Zuzana Vejrazkova

At Airbnb, tens of millions of information belongings exist in a fancy ecosystem to tell our enterprise and enhance our merchandise. The Information Administration group’s mission is to empower the corporate to handle its knowledge ecosystem at scale.

To do that, we want an correct understanding of the entire belongings in our ecosystem and the way they relate to one another. In different phrases, it requires correct metadata. Our knowledge administration platform Metis, named for the Greek goddess of excellent counsel, is our answer to make sure that reliable metadata will be captured, managed, and consumed at scale.

Metis is an evolution of our present basis of metadata merchandise inside Airbnb.

Dataportal was our first effort in direction of democratizing knowledge: efficiently enabling knowledge customers to search out trusted knowledge. It was an enormous boon to productiveness and fairly forward of its time.

As knowledge reliability and compliance rules turned essential, we wanted a extra complete and detailed understanding of how knowledge was remodeled. This led to our adoption of Apache Atlas as our knowledge lineage answer. Apache Atlas powers merchandise like SLA Tracker (see Visualizing Information timeliness at Airbnb), which mixes touchdown time metadata and lineage to allow debugging upstream knowledge delays.

As our necessities for metadata elevated, increasing to extra areas like value administration, knowledge high quality, and so on, our wants for a knowledge catalog have expanded:

  • Capacity to manipulate each the info and metadata describing it
  • Guardrails and suggestions to enhance knowledge high quality
  • Auditability of a dataset’s historical past, each for debugging & governance functions

We quickly discovered that knowledge administration needed to be pursued as a self-discipline, thus constructing Metis because the one-stop-shop for accessing all knowledge metadata.

Metis is made up of three core merchandise: Dataportal, Unified Metadata Service (UMS), and Lineage Service. Collectively, this platform permits Airbnb to handle tens of millions of information belongings throughout many domains. A brief checklist of belongings we help embrace:

  • Apache Hive and Trino datasets
  • Metrics and Dimensions, powered by Airbnb’s Metric Platform: Minerva
  • Charts and Dashboards from Apache Superset and Tableau®
  • Information Fashions, together with these licensed by Midas
  • Machine Studying options and fashions
  • Groups and staff of Airbnb (not technically a knowledge asset, however key to help prime quality possession and guarantee metadata stays updated for all of the above knowledge belongings)
Metis Structure

On a excessive degree, Metis consists of following elements:

Dataportal — serves as a catalog and administration UI for human customers.

Viaduct — Airbnb’s in-house GraphQL API layer modeling offline knowledge ecosystem.

UMS Core service — a backend service holding system schema and enterprise logic wanted for metadata administration.

Metadata storage:

  • MySQL — primarily storing important metadata that must be centrally managed
  • Lineage Graph — a centralized service amassing and serving knowledge lineage
  • Elasticsearch — serving search & discovery use circumstances

Offline Element — exterior to UMS Core service to carry out offline duties: e.g. offline metadata consistency examine, coverage enforcement.

Offline Dataset — offline export of metadata for analytics use circumstances.

Dataportal serves because the UI for Airbnb’s knowledge catalog and is a spot for individuals to search out and handle all of the belongings supported by Metis. It’s constructed as a Single Web page Utility utilizing React and TypeScript and is due to this fact versatile sufficient to serve the big number of workflows required for knowledge administration and governance. The frontend communicates with UMS and different companies by way of a GraphQL API; that is particularly essential as we need to forestall each sequential fetches of lineage data and over-fetching giant quantities of metadata to make sure a performant person expertise.

The Dataportal expertise begins with search, in order that each knowledge shoppers and knowledge house owners can discover the belongings they want. We’ve designed our search and discovery expertise with just a few ideas in thoughts:

  • Show related metadata straight within the search outcomes to assist individuals discover the precise asset they’re on the lookout for
  • Uprank prime quality and generally used knowledge belongings, within the case that the person is unaware of the precise asset they want

Because of this, search outcomes are inclined to return prime quality, licensed datasets, together with the outline, current person rely, and final time it was modified to assist the person discover which asset they need to choose:

Dataportal search consequence web page

As soon as the specified asset is positioned, the person can go to the Entity Web page to carry out a big number of consumption, administration, and governance actions. We construction all of the content material on the entity web page into tabs grouped by class of information or motion:

The various tabs obtainable for metadata on Hive Tables

Consumption and documentation associated tabs make it simple for individuals to discover ways to use this desk, with column and desk descriptions within the Configuration tab, proprietor and client knowledge on the Factors of contact tab, and additional particulars on the way to use the desk on the Documentation tab. Past that, these pages additionally permit customers to tackle administration actions, as seen within the under screenshots:

Anybody can tag columns that comprise private knowledge. Altering and eradicating tags require a overview to make sure that private knowledge is appropriately recognized in our warehouse.

The above screenshot highlights solely a subset of how we leveled up the Dataportal from a searchable knowledge catalog into the one centralized place to handle and govern all of your knowledge belongings.

Unified Metadata Service, or UMS, is the backend core of our centralized knowledge administration platform. It supplies:

  • A centralized schema and Graphql API layer on prime of it to entry metadata
  • A centralized relationship graph to attach siloed metadata
  • Centralized metadata administration capabilities to allow programs to fulfill compliance and governance necessities with out reinventing the wheel

The centralization of metadata into UMS prevents all metadata suppliers and shoppers from needing to combine with one another; as an alternative all suppliers and shoppers solely should combine with UMS:

Lowering integration factors for metadata

UMS performs varied roles throughout metadata integrations and use circumstances. In a decentralized knowledge ecosystem, we’re very opinionated about what metadata ought to be saved, replicated to, or served by UMS.

UMS helps proxying learn requests to many knowledge programs. This consists of proxying learn requests to:

  • Hive Metastore for desk schema and desk properties.
  • Lineage service for uncooked Hive desk knowledge lineage.
  • Information Governance service for knowledge governance standing for datasets.

UMS centrally manages just a few important enterprise metadata and shops in its personal metadata database with administration capabilities:

  • Validation and authorization for updates
  • Audit historical past
  • Approval workflow for delicate operations on important metadata

As a part of Airbnb’s Information High quality Initiative, we carried out knowledge high quality scores which are straight tied to every knowledge asset within the knowledge warehouse. Information high quality scores for datasets are generated in an offline method and ingested into UMS metadata database for on-line consumption.

Much like conventional knowledge catalog, UMS centrally manages indexes in an Elasticsearch cluster for various entities to energy knowledge discovery.

There are circumstances the place metadata must be saved or replicated into Metis storage layer. UMS integrates with metadata suppliers in quite a lot of paved mechanisms to ingest metadata leveraging Airbnb’s tech stack. These embrace:

  • Stream processing (Flink) jobs ingesting metadata change occasions.
  • ETL(Airflow) jobs that run day by day to drag from metadata suppliers and push to UMS.
  • Direct calls to UMS API.

Once we onboard a brand new metadata supplier, the important thing work concerned is figuring out product necessities and aligning on the scope of metadata integration, adopted by finalizing the precise integration mechanism.

The ultimate main piece of Metis is our Lineage Service. We adopted Apache Atlas as Airbnb’s knowledge lineage answer for Information Warehouse again in 2020.

At Airbnb, Apache Atlas holds a big lineage graph containing over 100 million nodes and 300 million edges. The first quantity of lineage knowledge comes from manufacturing Hive tables and a big quantity of intermediate Hive tables in our Information Warehouse.

We now have extensively custom-made and tuned Apache Atlas to deal with the big scale lineage occasions in our Information Warehouse:

  • Apply sharding technique on lineage occasions to extend parallelism.
  • Enhancing Atlas server code effectivity on prime of a graph database.
  • High quality tuning underlying storage programs backing the graph database for scalability and latency.
  • Learn path optimization and filtering help for accessing lineage knowledge extra effectively.

Atlas’s lineage-related elements, together with its Graph Engine (JanusGraph), Sort System, Ingest (with Hook integrations), and lineage API, have allowed us to effectively accumulate and serve lineage knowledge, offering worthwhile insights into the relationships between varied knowledge belongings and pipelines. It’s powering many important knowledge compliance, knowledge reliability and knowledge high quality merchandise. See Visualizing Information Timeliness at Airbnb.

As proven above, Airbnb’s method to knowledge administration has considerably developed over the previous 6 years. We began constructing Dataportal with a objective to “democratize knowledge” at Airbnb, and we now have Metis: a platform that permits anybody at Airbnb to look, uncover, eat, and handle all the info and metadata in our offline warehouse. Metis has been serving important roles throughout knowledge compliance, knowledge reliability, knowledge high quality initiatives and helps 1000+ knowledge customers each week.

Our future work will contain two key priorities: firstly, we are going to give attention to evolving our system structure and underlying expertise with the intention to maintain tempo with the fast evolution of our knowledge ecosystem. Secondly, we plan to increase our protection to extra programs and allow extra superior knowledge administration capabilities, reflecting our ongoing dedication to investing in knowledge right here at Airbnb.

Metis wouldn’t have been doable with out the members of the info administration group in addition to our cross useful and cross org collaborators. They embrace, however should not restricted to: Adam Kocoloski, Adam Wong, Cindy Yu, Dave Nagle, Erik Ritter, Jerry Wang, Jiaxin Ye, John Bodley, Jyoti Wadhwani, Liyin Tang, Michelle Thomas, Nathan Towery, Paul Ellwood, Sylvia Tomiyama, Vyl Chiang, Woody Zhou, Xiaobin Zheng, and Zuzana Vejrazkova.

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