Merge pull request #37060 from theredcat/lxc

Add lxc.get_pid and lxc.add_veth

salt/modules/lxc.py

@@ -12,6 +12,7 @@ lxc >= 1.0 (even beta alpha) is required
 from __future__ import absolute_import, print_function
 import datetime
 import copy
+import string
 import textwrap
 import difflib
 import logging
@@ -4659,3 +4660,103 @@ def apply_network_profile(name, network_profile, nic_opts=None, path=None):
                                      tofile='after'):
         diff += line
     return diff
+
+
+def get_pid(name, path=None):
+    '''
+    Returns a container pid.
+    Throw an exception if the container isn't running.
+
+    CLI Example:
+
+    .. code-block:: bash
+
+        salt '*' lxc.get_pid name
+    '''
+    if name not in list_(limit='running', path=path):
+        raise CommandExecutionError('Container {0} is not running, can\'t determine PID'.format(name))
+    info = __salt__['cmd.run']('lxc-info -n {0}'.format(name)).split("\n")
+    pid = [line.split(':')[1].strip() for line in info if re.match(r'\s*PID', line) != None][0]
+    return pid
+
+
+def add_veth(name, interface_name, bridge=None, path=None):
+    '''
+    Add a veth to a container.
+    Note : this function doesn't update the container config, just add the interface at runtime
+
+    name
+        Name of the container
+
+    interface_name
+        Name of the interface in the container
+
+    bridge
+        Name of the bridge to attach the interface to (facultative)
+
+    CLI Examples:
+
+    .. code-block:: bash
+
+        salt '*' lxc.add_veth container_name eth1 br1
+        salt '*' lxc.add_veth container_name eth1
+    '''
+
+    # Get container init PID
+    pid = get_pid(name, path=path)
+
+    # Generate a ramdom string for veth and ensure that is isn't present on the system
+    while True:
+        random_veth = 'veth'+''.join(random.choice(string.ascii_uppercase + string.digits) for _ in range(6))
+        if random_veth not in __salt__['network.interfaces']().keys():
+            break
+
+    # Check prerequisites
+    if not __salt__['file.directory_exists']('/var/run/'):
+        raise CommandExecutionError('Directory /var/run required for lxc.add_veth doesn\'t exists')
+    if not __salt__['file.file_exists']('/proc/{0}/ns/net'.format(pid)):
+        raise CommandExecutionError('Proc file for container {0} network namespace doesn\'t exists'.format(name))
+
+    if not __salt__['file.directory_exists']('/var/run/netns'):
+        __salt__['file.mkdir']('/var/run/netns')
+
+    # Ensure that the symlink is up to date (change on container restart)
+    if __salt__['file.is_link']('/var/run/netns/{0}'.format(name)):
+        __salt__['file.remove']('/var/run/netns/{0}'.format(name))
+
+    __salt__['file.symlink']('/proc/{0}/ns/net'.format(pid), '/var/run/netns/{0}'.format(name))
+
+    # Ensure that interface doesn't exists
+    interface_exists = 0 == __salt__['cmd.retcode']('ip netns exec {netns} ip address list {interface}'.format(
+            netns=name,
+            interface=interface_name
+        ))
+
+    if interface_exists:
+        raise CommandExecutionError('Interface {interface} already exists in {container}'.format(
+                interface=interface_name,
+                container=name
+            ))
+
+    # Create veth and bring it up
+    if __salt__['cmd.retcode']('ip link add name {veth} type veth peer name {veth}_c'.format(veth=random_veth)) != 0:
+        raise CommandExecutionError('Error while creating the veth pair {0}'.format(random_veth))
+    if __salt__['cmd.retcode']('ip link set dev {0} up'.format(random_veth)) != 0:
+        raise CommandExecutionError('Error while bringing up host-side veth {0}'.format(random_veth))
+
+    # Attach it to the container
+    attached = 0 == __salt__['cmd.retcode']('ip link set dev {veth}_c netns {container} name {interface_name}'.format(
+            veth=random_veth,
+            container=name,
+            interface_name=interface_name
+        ))
+    if not attached:
+        raise CommandExecutionError('Error while attaching the veth {veth} to container {container}'.format(
+                veth=random_veth,
+                container=name
+            ))
+
+    __salt__['file.remove']('/var/run/netns/{0}'.format(name))
+
+    if bridge is not None:
+        __salt__['bridge.addif'](bridge, random_veth)