About

Procszoo is a small Python module that gives you full power to manage your processes by Linux namespaces.

Contents

• wiki
• Goals
• Resources
• Requirements
• Install
• Building
• Try It
• Getting Your Feet Wet with the procszoo Module
• Networks
• Docs
• Known Issues
• Exported Functions, Objects, and Helpful CLI
• Test Platforms

Goals

Procszoo aims to provide you a simple but complete tool and you can use it as a DSL or an embedded programming language which let you operate Linux namespaces by Python.

Procszoo gives a smart init program. I get it from baseimage-docker. Thanks a lot, you guys.

Procszoo does not require new version Python (but we support python3, too) and Linux kernel.

Resources

• IRC channel: #procszoo on freenode.net

Requirements

Procszoo only requires Python standard libraries and the following packages

# if you want python3, pls install following package's python3 version
# on RHEL/CentOS >= 6
sudo yum -y install autoconf gcc make glibc-headers
sudo yum -y install python-devel python-setuptools
# Debain/Ubuntu
sudo apt-get -y install autoconf gcc make libc6-dev
sudo appt-get -y install python-dev python-setuptools

Install

1. You can install the procszoo by setuptools

   git clone https://github.com/xning/procszoo.git
   cd procszoo && sudo ./setup.py install
   

2. You can install the procszoo by pip

   sudo pip install procszoo
   

Building

If you don't want to install it, then you can just clone it and do as follows to try it,

git clone https://github.com/xning/procszoo.git
cd procszoo && make

By default, the above command will build the program for your default Python version. If you want to build for another Python version, just specify your desired Python interpretor through the PYTHON variable of the make command. Eg. To build for Python 3:

make PYTHON=/usr/bin/python3

If you will clone the procszoo in your home directory, On the RHEL/CentOS/Scientific Linux/Fedora, the default mode of your home directory is 0400, this will cause trouble, hence change it

chmod go+rx ${HOME}

Try It

Now you can try it in an interactive shell as follows (we suppose you installed the procszoo)

richard_parker -l                       # what namsepaces are available?
richard_parker --available-c-functions  # what C functions are available?
richard_parker                          # get an interactive shell

If your Linux kernel doesn't support "user" namespaces, e.g., RHEL6/CentOS6, RHEL7/CentOS7, you need super user privileges

sudo richard_parker

And now, you can check sth that we are in namespaces

• programs get small pids, e.g., 1, 2, etc., and there is only lo device and it is down

  ps -ef 
  ifconfig -a
  

• open another terminal, we can see that the namespaces entries are different from our namespaces

  ls -l /proc/self/ns
  

• if the kernel support and enable "user" namespaces, we are superuser now

  id
  

• if you have trouble to try the above steps, please reference Known Issues.

Getting Your Feet Wet with the procszoo module

If you want to enable each namespaces that your kernel supports

from procszoo.c_functions import *

if __name__ == "__main__":
    spawn_namespaces()

If you need run your own program instead of an interactive shell,

from procszoo.c_functionss import *

if __name__ == "__main__":
    spawn_namespaces(nscmd=path_to_your_program)

Networks

Let's add network to the new namespaces.

Because we will mount namespaces entries by the bind flag, we need run richard_parker as the super user.

Except the shell that richard_parker will open, we need another interactive shell to make veth devices and add them to the new "net" namespace.

• create a mount point

  mkdir /tmp/ns
  

• create namespaces

  sudo richard_parker --ns-bind-dir=/tmp/ns
  

• in richard_parker, configure the lo device

  ip link set lo up
  

• in a new terminal, remount the /tmp/ns/net to /var/run/netns/net so ip command could operate it

  [ -d /var/run/netns ] | sudo mkdir -p  /var/run/netns
  sudo touch /var/run/netns/ns
  sudo mount --bind /tmp/ns/net /var/run/netns/ns
  

• in the new terminal, create two devices and set one of it to the new namespace in a new terminal

  sudo ip link add veth0 type veth peer name veth1
  sudo ip link set dev veth1 netns ns
  

• in the new terminal, configure veth0 device

  sudo ip link set veth0 up
  sudo ip addr add 192.168.0.10/24 broadcast 192.168.0.255 dev veth0
  

• in richard_parker, configure veth1

  ip link set veth1 up
  ip addr add 192.168.0.11/24 broadcast 192.168.0.255 dev veth1
  

• let's say "hello" from the new terminal

  ping -c 3 192.168.0.11
  

• let's say "hello" from richard_parker

  ping -c 3 192.168.0.10
  

Docs

• namespaces(7)

• unshare(2)

• setns(2)

• ip(8)

• mount(2)

• pivot_root(2)

• Linux namespaces

• Docker and the PID 1 zombie reaping problem

• Resource management:Linux kernel Namespaces and cgroups

• Containers and Namespaces in the Linux Kernel

Known Issues

• os.execv complains "permission deny"

  If running richard_parker failed on RHEL/CentOS/Fedora, and get following error message like this

      os.execv(...)
  OSError: [Errno 13] Permission denied
  

  That's not a bug, please see the comment.

• "ip netns" failed on RHRL6/CentOS6 and gave error messages as follows

  Object "nets" is unknown, try "ip help".
  

  We need a more latest iproute package, to do that pls reference here

Exported Functions, Objects, and Helpful CLI

The procszoo.utils exported following functions and objects, and I don't think that you need learn them all

• objects

  • workbench

• key functions

  • spawn_namespaces
  • check_namespaces_available_status

• helpful functions

  • atfork
  • sched_getcpu
  • mount
  • umount
  • umount2
  • unshare
  • setns
  • gethostname
  • sethostname
  • getdomainname
  • setdomainname
  • pivot_root
  • to_unicode
  • to_bytes
  • adjust_namespaces
  • get_namespace
  • get_available_propagations
  • get_uid_from_name_or_uid
  • get_gid_from_name_or_gid
  • get_uid_by_name
  • get_gid_by_name
  • get_name_by_uid
  • get_name_by_gid
  • get_current_users_and_groups
  • getresuid
  • getresgid
  • setresuid
  • setresgid
  • show_namespaces_status
  • show_available_c_functions
  • cgroup_namespace_available
  • ipc_namespace_available
  • net_namespace_available
  • mount_namespace_available
  • pid_namespace_available
  • user_namespace_available
  • uts_namespace_available
  • unregister_fork_handlers

• Exceptions

  • CFunctionBaseException
  • CFunctionNotFound
  • NamespaceGenericException
  • UnknownNamespaceFound
  • UnavailableNamespaceFound
  • NamespaceSettingError

• Helpful CLI

  • richard_parker
  • mamaji

Test Platforms

I test the richard_parker and these scripts in tests/ on following archs

• CentOS 6(x86)
• CentOS 7(x86_64)
• Fedora 24(x86_64)
• ubuntu 12.04(armv7l)
• Ubuntu 14.04(x86_64)
• Ubuntu 16.04(x86_64)
• openSUSE 42(x86_64)