https://github.com/zalando/python-nsenter

Enter kernel namespaces from Python
https://github.com/zalando/python-nsenter

docker linux-kernel namespaces nsenter python

Last synced: 2 months ago
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Enter kernel namespaces from Python

• Host: GitHub
• URL: https://github.com/zalando/python-nsenter
• Owner: zalando
• License: other
• Archived: true
• Created: 2014-09-15T11:35:23.000Z (almost 10 years ago)
• Default Branch: master
• Last Pushed: 2020-03-27T16:18:56.000Z (over 4 years ago)
• Last Synced: 2024-04-16T14:08:22.814Z (2 months ago)
• Topics: docker, linux-kernel, namespaces, nsenter, python
• Language: Python
• Homepage: https://pypi.python.org/pypi/nsenter
• Size: 29.3 KB
• Stars: 138
• Watchers: 44
• Forks: 21
• Open Issues: 5
• Metadata Files:
  • Readme: README.rst
  • Contributing: CONTRIBUTING.rst
  • License: LICENSE

Lists

• awesome-linux-containers - python-nsenter
• awesome-linux-containers - python-nsenter

README

        
=======

NSEnter

=======

.. image:: https://travis-ci.org/zalando/python-nsenter.svg?branch=master

   :target: https://travis-ci.org/zalando/python-nsenter

   :alt: Travis CI build status

**NSEnter** is a Python package that enables you to enter Linux kernel namespaces — mount, IPC, net, PID, user and UTS — with a single, simple "setns" syscall. The command line interface is similar to the nsenter_ C program.

Project Origins

---------------

When working with Docker_ containers, questions usually arise about how to connect into a running container without starting an explicit SSH daemon (`which is considered a bad idea`_). One way is to use Linux Kernel namespaces, which Docker uses to restrict the view from within containers. 

The ``util-linux`` package provides the ``nsenter`` command line utility, but `Ubuntu 16.04 LTS`_ unfortunately does not. Jérôme Petazzoni provides a `Docker recipe`_ for ``nsenter`` on GitHub, or you can compile ``nsenter`` `from source`_. As there is only one simple syscall to enter a namespace, we can do the call directly from within Python using the ``ctypes`` module. We bundled this syscall to create NSEnter.

Additional Links

````````````````

- "Entering Kernel Namespaces from Python," Zalando Tech `blog post`_

- On PyPi_

Requirements

````````````

- Python 2.6 or higher

Installation

````````````

From PyPI::

    sudo pip3 install nsenter

From git source::

    python3 setup.py install

Usage

`````

Example of command line usage::

    docker run -d --name=redis -t redis

    sudo nsenter --all --target=`docker inspect --format '{{ .State.Pid }}' redis` /bin/bash

Example of usage from Python:

.. code:: python

    import subprocess

    from nsenter import Namespace

    with Namespace(mypid, 'net'):

        # output network interfaces as seen from within the mypid's net NS:

        subprocess.check_output(['ip', 'a'])

    # or enter an arbitrary namespace:

    with Namespace('/var/run/netns/foo', 'net'):

        # output network interfaces as seen from within the net NS "foo":

        subprocess.check_output(['ip', 'a'])

Development Status

``````````````````

This project works as-is. There are currently no plans to extend it, but if you have an idea please submit an Issue to the maintainers.

License

-------

See file_.

.. _Docker: https://www.docker.com/

.. _which is considered a bad idea: https://jpetazzo.github.io/2014/06/23/docker-ssh-considered-evil/

.. _Ubuntu 16.04 LTS: https://askubuntu.com/questions/439056/why-there-is-no-nsenter-in-util-linux

.. _Docker recipe: https://github.com/jpetazzo/nsenter

.. _from source: https://askubuntu.com/questions/439056/why-there-is-no-nsenter-in-util-linux

.. _nsenter: http://man7.org/linux/man-pages/man1/nsenter.1.html

.. _blog post: http://tech.zalando.com/posts/entering-kernel-namespaces-with-python.html

.. _PyPi: https://pypi.python.org/pypi/nsenter

.. _file: https://github.com/zalando/python-nsenter/blob/master/LICENSE