ipython server can't launch: No module named notebook.notebookapp

This should fix the issue:

pip install jupyter

I received the same problem when upgrading IPython. At the moment the answer was written, it was a bug linked to the latest 4 version. If a similar problem occurs for which you wish to switch back to the stable version 3.2.1:

pip uninstall -y IPython
pip install ipython==3.2.1

• note: the -y option indicates "yes I want to uninstall" with no interaction.
• note 2: possible duplicate in ImportError: No module named notebook.notebookapp

So to close this thread, and in case it helps anyone, my mistake was to have installed and used the dev version of ipython blindly following a tutorial, thinking I was using the anaconda instance I installed earlier (which was not even in my PATH).

Anyhow I:

• uninstalled that ipython dev instance
• added anaconda/bin to my zsh path (add it to ~/.zshrc - that's why it was not even in my path after install) // at this point the server was launching fine but I couldn't access it in my browser >> firewall problems.
• opened my port of choice in my firewall (help for linode or ubuntu in general)

And everything works fine now.