fdb-zk

fdb-zk is a FoundationDB layer that mimics the behavior of Zookeeper. It is installed as a local service to an application, and replaces connections to and the operation of a ZooKeeper cluster.

While the core operations are implemented, fdb-zk has not been vetted for proper production use.

Talk & Slides

Learn about how the layer works in greater detail:

• In video format
• In slidedeck format

Architecture

Similar to the FoundationDB Document Layer, fdb-zk is hosted locally and translates requests for the target service into FoundationDB transactions.

Applications can continue to use their preferred Zookeeper clients:

┌──────────────────────┐     ┌──────────────────────┐
│ ┌──────────────────┐ │     │ ┌──────────────────┐ │
│ │   Application    │ │     │ │   Application    │ │
│ └──────────────────┘ │     │ └──────────────────┘ │
│           │          │     │           │          │
│           │          │     │           │          │
│       ZooKeeper      │     │       ZooKeeper      │
│        protocol      │     │        protocol      │
│           │          │     │           │          │
│           │          │     │           │          │
│           ▼          │     │           ▼          │
│ ┌──────────────────┐ │     │ ┌──────────────────┐ │
│ │  fdb-zk service  │ │     │ │  fdb-zk service  │ │
│ └──────────────────┘ │     │ └──────────────────┘ │
└──────────────────────┘     └──────────────────────┘
            │                            │
         FDB ops                      FDB ops
            │                            │
            ▼                            ▼
┌───────────────────────────────────────────────────┐
│                   FoundationDB                    │
└───────────────────────────────────────────────────┘

Features

fdb-zk implements the core Zookeeper 3.4.6 API:

• create
• exists
• delete
• getData
• setData
• getChildren
• watches
• session management

It partially implements:

• multi transactions (reads are fine, but there are no read-your-writes)

It does not yet implement:

• getACL/setACL
• quotas

Initial Design Discussion

https://forums.foundationdb.org/t/fdb-zk-rough-cut-of-zookeeper-api-layer/1278/

Building with Bazel

• Compiling: bazel build //:fdb_zk
• Testing: bazel test //:fdb_zk_test
• Dependencies: bazel query @maven//:all --output=build

License

fdb-zk is under the Apache 2.0 license. See the LICENSE file for details.