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 <mailto:SIMCOP@cpan.org>