python3 tkinter ubuntu trusty does not work under virtual environment
<p>I installed python3-tk on an ubuntu trusty docker container.(apt-get install python3-tk)</p>

<pre><code>&gt; python3
Python 3.4.3 (default, Oct 14 2015, 20:28:29) 
[GCC 4.8.4] on linux
Type "help", "copyright", "credits" or "license" for more information.
&gt;&gt;&gt; import tkinter
&gt;&gt;&gt; import tkinter as tk
&gt;&gt;&gt; 
</code></pre>

<p>So far so good. However, for different reasons, I need to run a loaded python3 virtualenv in same container.
When I activate the virtual environment:</p>

<pre><code>(env_py34)root@8a7953c24d4f:/home# python
Python 3.4.3 (default, Oct 14 2015, 20:28:29) 
[GCC 4.8.4] on linux
Type "help", "copyright", "credits" or "license" for more information.
&gt;&gt;&gt; import tkinter as tk
Traceback (most recent call last):
  File "/usr/lib/python3.4/tkinter/__init__.py", line 39, in &lt;module&gt;
    import _tkinter
ImportError: No module named '_tkinter'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  File "/usr/lib/python3.4/tkinter/__init__.py", line 41, in &lt;module&gt;
    raise ImportError(str(msg) + ', please install the python3-tk package')
ImportError: No module named '_tkinter', please install the python3-tk package
&gt;&gt;&gt; 
</code></pre>

<p>Versions of python are identical.
How come the virtual environment did not inherit python3-tk from the python3 installation? How can I install python3-tk inside the virtual environment?</p>