Installing tensorboard does not install tensorflow

[cancan101]

$ pip install tensorboard

Does not install tensorflow
I am on tensorboard==1.8.0.

$ tensorboard
Traceback (most recent call last):
  File "/Users/alex/.virtualenvs/tb/bin/tensorboard", line 7, in <module>
    from tensorboard.main import run_main
  File "/Users/alex/.virtualenvs/tb/lib/python3.6/site-packages/tensorboard/main.py", line 28, in <module>
    import tensorflow as tf
ModuleNotFoundError: No module named 'tensorflow'

[nfelt]

Closing since this is by design. TensorBoard expects you to have a tensorflow installation in the python environment in which you install TensorBoard, but it intentionally doesn't depend on TensorFlow's pip package directly because people install TensorFlow in many different ways (tensorflow, tensorflow-gpu, from source, etc.). Note that tensorflow/tensorflow-gpu also already depend on tensorboard, and that's how most users obtain tensorboard.

See e.g. https://www.tensorflow.org/programmers_guide/summaries_and_tensorboard#setup