UCX depends on the following system libraries being present:

  • For MOFED 4.x support: libibcm, libibverbs and librdmacm. Ideally installed from Mellanox OFED Drivers

  • For MOFED 5.x support: Mellanox OFED Drivers

  • For system topology identification: libnuma (numactl on Enterprise Linux)

Please install the packages above with your Linux system’s package manager. When building from source you will also need the *-dev (*-devel on Enterprise Linux) packages as well.


Some preliminary Conda packages can be installed as so. Replace <CUDA version> with either 11.0 or 11.2. These are available both on rapidsai and rapidsai-nightly.

With GPU support:

conda create -n ucx -c conda-forge -c rapidsai \
  cudatoolkit=<CUDA version> ucx-proc=*=gpu ucx ucx-py python=3.7

Without GPU support:

conda create -n ucx -c conda-forge -c rapidsai \
  ucx-proc=*=cpu ucx ucx-py python=3.7


The following instructions assume you’ll be using ucx-py on a CUDA enabled system and is in a Conda environment.


As of version 0.15, the UCX conda package build will no longer include IB/RDMA support. This is largely due to compatibility issues between OFED versions. We do however provide instructions below for how to build UCX with IB/RDMA support in the UCX + OFED section.

Build Dependencies

conda create -n ucx -c conda-forge \
    automake make libtool pkg-config \
    psutil \
    "python=3.7" setuptools "cython>=0.29.14,<3.0.0a0"

Test Dependencies

conda install -n ucx -c rapidsai -c nvidia -c conda-forge \
    pytest pytest-asyncio \
    cupy "numba>=0.46" rmm \

UCX >= 1.11.1

Instructions for building UCX >= 1.11.1 (minimum version supported by UCX-Py), make sure to change git checkout v1.11.1 to a newer version if desired:

conda activate ucx
git clone
cd ucx
git checkout v1.11.1
mkdir build
cd build
# Performance build
../contrib/configure-release --prefix=$CONDA_PREFIX --with-cuda=$CUDA_HOME --enable-mt
# Debug build
../contrib/configure-devel --prefix=$CONDA_PREFIX --with-cuda=$CUDA_HOME --enable-mt
make -j install


As noted above, the UCX conda package no longer builds support for IB/RDMA. To build UCX with IB/RDMA support first confirm OFED is installed properly:

(ucx) user@dgx:~$ ofed_info -s

If OFED drivers are not installed on the machine, you can download drivers at directly from Mellanox. For versions older than 5.1 click on, archive versions.

Building UCX >= 1.11.1 as shown previously should automatically include IB/RDMA support if available in the system. It is possible to explicitly activate those, ensuring the system satisfies all dependencies or fail otherwise, by including the --with-rdmacm and --with-verbs build flags. For example:

../contrib/configure-release \
--enable-mt \
--prefix="$CONDA_PREFIX" \
--with-cuda="$CUDA_HOME" \
--enable-mt \
--with-rdmacm \


conda activate ucx
git clone
cd ucx-py
pip install -v .
# or for develop build
pip install -v -e .