NAME

Sys::Linux::Namespace - A Module for setting up linux namespaces

SYNOPSIS

use Sys::Linux::Namespace;

# Create a namespace with a private /tmp
my $ns1 = Sys::Linux::Namespace->new(private_tmp => 1);

$ns1->setup(code => sub {
    # This code has it's own completely private /tmp filesystem
    open(my $fh, "</tmp/private");
    print $fh "Hello Void";
});	

# The private /tmp has been destroyed and we're back to our previous state

# Let's do it again, but this time with a private PID space too
my $ns2 = Sys::Linux::Namespace->new(private_tmp => 1, private_pid => 1);
$ns2->setup(code => sub {
    # I will only see PID 1.  I can fork anything I want and they will only see me
    # if I die they  die too.
    use Data::Dumper;
    print Dumper([glob "/proc/*"]);
});
# We're back to our previous global /tmp and PID namespace
# all processes and private filesystems have been removed

# Now let's set up a private /tmp 
$ns1->setup();
# We're now permanently (for this process) using a private /tmp.

REQUIREMENTS

This module requires your script to either have CAP_SYS_ADMIN, usually by running as root. Without that it will fail to setup the namespaces and cause your program to exit.

METHODS

new

Construct a new Sys::Linux::Namespace object. This collects all the options you want to enable, but does not engage them.

setup

Engage the namespaces. Without a code parameter it will alter the current process and place it whatever namespaces are configured. If called with a code parameter, it will run the coderef in the namespace with a child process. This method also accepts an overriding code parameter so you can run multiple coderefs in a configured namespace without creating new objects.

OPTIONS

private_mount

Setup a private mount namespace, this makes every currently mounted filesystem private to our process. This means we can unmount and mount new filesystems without other processes seeing the mounts.

private_tmp

Sets up the private mount namespace as above, but also automatically sets up /tmp to be a clean private tmpfs mount. Takes either a true value, or a hashref with options to pass to the mount syscall. See man 8 mount for a list of possible options.

private_pid

Create a private PID namespace. This requires a code parameter either to new() or to setup()

private_net

TODO This is not yet implemented. Once done however, it will allow a child process to execute with a private network preventing communication. Will require a code parameter to new() or setup.

private_ipc

Create a private IPC namespace.

private_user

Create a new user namespace. See man 7 user_namespaces for more information.

private_uts

Create a new UTS namespace. This will let you safely change the hostname of the system without affect anyone else.

private_sysvsem

Create a new System V Semaphore namespace. This will let you create new semaphores without anyone else touching them.

AUTHOR

Ryan Voots simcop@cpan.org