The error you're hitting happens because cx_Oracle relies on the Oracle Instant Client libraries to talk to remote Oracle databases—libaio is just a basic prerequisite, but you're missing the actual Oracle client binaries. Here's a single command chain that handles all dependencies, sets up the Oracle Instant Client properly, and installs cx_Oracle correctly in your Ubuntu 16.04 Docker environment:

apt-get update && apt-get install -y libaio1 libaio-dev wget unzip && \
wget https://download.oracle.com/otn_software/linux/instantclient/185000/instantclient-basic-linux.x64-18.5.0.0.0dbru.zip && \
unzip instantclient-basic-linux.x64-18.5.0.0.0dbru.zip && \
mv instantclient_18_5 /usr/lib/oracle/18.5/client64/lib && \
mkdir -p /usr/lib/oracle/18.5/client64/include && \
ln -s /usr/lib/oracle/18.5/client64/lib/libclntsh.so.18.1 /usr/lib/oracle/18.5/client64/lib/libclntsh.so && \
echo "/usr/lib/oracle/18.5/client64/lib" > /etc/ld.so.conf.d/oracle-instantclient.conf && \
ldconfig && \
pip install cx_Oracle && \
rm instantclient-basic-linux.x64-18.5.0.0.0dbru.zip

Breakdown of what this does: #

• Updates apt and installs libaio (required for Oracle client I/O operations) plus wget/unzip to fetch and extract the client package
• Downloads Oracle Instant Client 18.5 (the latest version fully compatible with Ubuntu 16.04)
• Moves the client files to a standard system path for Oracle libraries
• Creates a symlink for libclntsh.so (cx_Oracle looks for this unversioned filename, while the package includes a versioned one)
• Configures the system's dynamic linker to recognize the Oracle library path
• Refreshes the linker cache so changes take effect immediately
• Installs cx_Oracle via pip
• Cleans up the downloaded zip file to keep your Docker image small

If you're building a Dockerfile, you can add this command directly (or split it into separate RUN commands for better layer caching). Once this completes, you should be able to import cx_Oracle and connect to your remote Oracle database without any issues.

内容的提问来源于stack exchange，提问作者Joe