edit: I now recommend you use Singularity to get Tensorflow up in an Ubuntu 16 LTS image.
Following on from more manual instructions posted before, just a quick mention that to install Tensorflow 1.8 on CentOS 6, or presumably RHEL 6 and such there’s a semi-automatic script here on GitHub.
You can run this, and it’ll download dependencies, finish patching up the source and give you instructions on finishing the last few steps yourself to get a .whl file you can go and install with pip.