Native Rust HDFS client

This is a proof-of-concept HDFS client written natively in Rust. All other clients I have found in any other language are simply wrappers around libhdfs and require all the same Java dependencies, so I wanted to see if I could write one from scratch given that HDFS isn't really changing very often anymore. Several basic features are working, however it is not nearly as robust and the real HDFS client.

What this is not trying to do is implement all HDFS client/FileSystem interfaces, just things involving reading and writing data.

Supported HDFS features

Here is a list of currently supported and unsupported but possible future features.

HDFS Operations

• Listing
• Reading
• Writing
• Rename
• Delete

HDFS Features

• Name Services
• Observer reads (state ID tracking is supported, but needs improvements on tracking Observer/Active NameNode)
• ViewFS
• Router based federation
• Erasure coded reads
  • RS schema only, no support for RS-Legacy or XOR
• Erasure coded writes

Security Features

• Kerberos authentication (GSSAPI SASL support)
• Token authentication (DIGEST-MD5 SASL support, no encryption support)
• NameNode SASL connection
• DataNode SASL connection
• DataNode data transfer encryption
• Encryption at rest (KMS support)

Supported HDFS Settings

The client will attempt to read Hadoop configs core-site.xml and hdfs-site.xml in the directories $HADOOP_CONF_DIR or if that doesn't exist, $HADOOP_HOME/etc/hadoop. Currently the supported configs that are used are:

• fs.defaultFS - Client::default() support
• dfs.ha.namenodes - name service support
• dfs.namenode.rpc-address.* - name service support
• fs.viewfs.mounttable.*.link.* - ViewFS links
• fs.viewfs.mounttable.*.linkFallback - ViewFS link fallback

All other settings are generally assumed to be the defaults currently. For instance, security is assumed to be enabled and SASL negotiation is always done, but on insecure clusters this will just do SIMPLE authentication. Any setups that require other customized Hadoop client configs may not work correctly.

Building

Mac

brew install gsasl krb5
# You might need these env vars on newer Macs
export BINDGEN_EXTRA_CLANG_ARGS="-I/opt/homebrew/include"
export LIBRARY_PATH=/opt/homebrew/lib
cargo build --features token,kerberos

Ubuntu

apt-get install clang libkrb5-dev libgsasl-dev
cargo build --features token,kerberos

Crate features

• token - enables token based DIGEST-MD5 authentication support. This uses the gsasl native library and only supports authentication, not integrity or confidentiality
• kerberos - enables kerberos GSSAPI authentication support. This uses the libgssapi crate and supports integrity as well as confidentiality
• object_store - provides an object_store wrapper around the HDFS client

Running tests

The tests are mostly integration tests that utilize a small Java application in rust/mindifs/ that runs a custom MiniDFSCluster. To run the tests, you need to have Java, Maven, Hadoop binaries, and Kerberos tools available and on your path. Any Java version between 8 and 17 should work.

cargo test -p hdfs-native --features token,kerberos,intergation-test

Python tests

See the Python README