Ansible is one of most popular Configuration Management Systems nowadays. After it was acquired by Red Hat in 2015 Ansible has reached numbers of thousands of contributors and became maybe one of most used deployment and orchestration tools. Its use-cases are quite impressive.
Ansible works by SSH connections to remote hosts. It opens SSH session, logs in to the shell, copy python code via network and create a temporary file on remote hosts with this code. In the next step, it executes the current file with python interpreter. All this workflow is pretty heavy and there are multiple ways to make it faster and lighter.