JupyterHub Notebook：无法导入已安装的pip包

Question

我有一个在kubernetes集群中运行的JupyterHub。 如果我尝试基于以下docker镜像启动一个新笔记本，则我将无法以某种方式导入笔记本中已安装的tensorflow软件包。

笔记本映像的Dockerfile：

ARG BASE_CONTAINER=jupyter/base-notebook
FROM $BASE_CONTAINER

# Build as jupyterhub/singleuser
# Run with the DockerSpawner in JupyterHub

MAINTAINER Project Jupyter <jupyter@googlegroups.com>

ADD install_jupyterhub /tmp/install_jupyterhub
ARG JUPYTERHUB_VERSION=0.9.6
# install pinned jupyterhub and ensure notebook is installed
RUN python3 /tmp/install_jupyterhub && \
python3 -m pip install notebook

RUN pip install --user --upgrade tensorflow==2.0.0-alpha0  # install in $HOME

导入尝试失败：

import tensorflow as tf
--> Not found

笔记本映像的Dockerfile有什么问题？