Factoring out PXE and TFTP functions

Multiple drivers need to support neutron and Ironic's PXE and TFTP
server. Factoring them out into a common file will make that
transition possible. This moves all the generic calls into neutron
and reconfigures the PXE driver to work with the new functions.

Change-Id: I181ffabe673636b628329592e623e6425da54d6d

etc/ironic/ironic.conf.sample

@@ -904,13 +904,6 @@
 # is created. (string value)
 #default_ephemeral_format=ext4
 
-# IP address of Ironic compute node's tftp server. (string
-# value)
-#tftp_server=$my_ip
-
-# Ironic compute node's tftp root path. (string value)
-#tftp_root=/tftpboot
-
 # Directory where images are stored on disk. (string value)
 #images_path=/var/lib/ironic/images/
 
@@ -958,3 +951,17 @@
 #libvirt_uri=qemu:///system
 
 
+[tftp]
+
+#
+# Options defined in ironic.common.tftp
+#
+
+# IP address of Ironic compute node's tftp server. (string
+# value)
+#tftp_server=$my_ip
+
+# Ironic compute node's tftp root path. (string value)
+#tftp_root=/tftpboot
+
+

ironic/common/neutron.py

@@ -21,6 +21,7 @@
 from ironic.api import acl
 from ironic.common import exception
 from ironic.common import keystone
+from ironic.common import tftp
 from ironic.openstack.common import log as logging
 
 
@@ -30,10 +31,12 @@
                help='URL for connecting to neutron.'),
     cfg.IntOpt('url_timeout',
                default=30,
-               help='Timeout value for connecting to neutron in seconds.'),
-   ]
+               help='Timeout value for connecting to neutron in seconds.')
+    ]
+
 
 CONF = cfg.CONF
+CONF.import_opt('my_ip', 'ironic.netconf')
 CONF.register_opts(neutron_opts, group='neutron')
 acl.register_opts(CONF)
 LOG = logging.getLogger(__name__)
@@ -105,3 +108,54 @@ def update_port_address(self, port_id, address):
             LOG.exception(_("Failed to update MAC address on Neutron port %s."
                            ), port_id)
             raise exception.FailedToUpdateMacOnPort(port_id=port_id)
+
+
+def get_node_vif_ids(task):
+    """Get all Neutron VIF ids for a node.
+
+    This function does not handle multi node operations.
+
+    :param task: a TaskManager instance.
+    :returns: A dict of the Node's port UUIDs and their associated VIFs
+
+    """
+    port_vifs = {}
+    for port in task.ports:
+        vif = port.extra.get('vif_port_id')
+        if vif:
+            port_vifs[port.uuid] = vif
+    return port_vifs
+
+
+def update_neutron(task, pxe_bootfile_name):
+    """Send or update the DHCP BOOT options to Neutron for this node."""
+    options = tftp.dhcp_options_for_instance(pxe_bootfile_name)
+    vifs = get_node_vif_ids(task)
+    if not vifs:
+        LOG.warning(_("No VIFs found for node %(node)s when attempting to "
+                      "update Neutron DHCP BOOT options."),
+                      {'node': task.node.uuid})
+        return
+
+    # TODO(deva): decouple instantiation of NeutronAPI from task.context.
+    #             Try to use the user's task.context.auth_token, but if it
+    #             is not present, fall back to a server-generated context.
+    #             We don't need to recreate this in every method call.
+    api = NeutronAPI(task.context)
+    failures = []
+    for port_id, port_vif in vifs.iteritems():
+        try:
+            api.update_port_dhcp_opts(port_vif, options)
+        except exception.FailedToUpdateDHCPOptOnPort:
+            failures.append(port_id)
+
+    if failures:
+        if len(failures) == len(vifs):
+            raise exception.FailedToUpdateDHCPOptOnPort(_(
+                "Failed to set DHCP BOOT options for any port on node %s.") %
+                task.node.uuid)
+        else:
+            LOG.warning(_("Some errors were encountered when updating the "
+                          "DHCP BOOT options for node %(node)s on the "
+                          "following ports: %(ports)s."),
+                          {'node': task.node.uuid, 'ports': failures})

ironic/common/tftp.py

@@ -0,0 +1,125 @@
+#
+# Copyright 2014 Rackspace, Inc
+# All Rights Reserved
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import os
+
+import jinja2
+from oslo.config import cfg
+
+from ironic.common import utils
+from ironic.drivers import utils as driver_utils
+from ironic.openstack.common import fileutils
+from ironic.openstack.common import log as logging
+
+
+tftp_opts = [
+    cfg.StrOpt('tftp_server',
+               default='$my_ip',
+               help='IP address of Ironic compute node\'s tftp server.',
+               deprecated_group='pxe'),
+    cfg.StrOpt('tftp_root',
+               default='/tftpboot',
+               help='Ironic compute node\'s tftp root path.',
+               deprecated_group='pxe')
+    ]
+
+CONF = cfg.CONF
+CONF.register_opts(tftp_opts, group='tftp')
+
+LOG = logging.getLogger(__name__)
+
+
+def create_pxe_config(task, pxe_options, pxe_config_template):
+    """Generate PXE configuration file and MAC symlinks for it."""
+    node = task.node
+    fileutils.ensure_tree(os.path.join(CONF.tftp.tftp_root,
+                                       node.uuid))
+    fileutils.ensure_tree(os.path.join(CONF.tftp.tftp_root,
+                                       'pxelinux.cfg'))
+
+    pxe_config_file_path = get_pxe_config_file_path(node.uuid)
+    pxe_config = build_pxe_config(node, pxe_options, pxe_config_template)
+    utils.write_to_file(pxe_config_file_path, pxe_config)
+    _write_mac_pxe_configs(task)
+
+
+def clean_up_pxe_config(task):
+    """Clean up the TFTP environment for the task's node."""
+    node = task.node
+
+    utils.unlink_without_raise(get_pxe_config_file_path(node.uuid))
+    for port in driver_utils.get_node_mac_addresses(task):
+        utils.unlink_without_raise(get_pxe_mac_path(port))
+
+    utils.rmtree_without_raise(os.path.join(CONF.tftp.tftp_root, node.uuid))
+
+
+def _write_mac_pxe_configs(task):
+    """Create a file in the PXE config directory for each MAC so regardless
+    of which port boots first, they'll get the same PXE config.
+    """
+    pxe_config_file_path = get_pxe_config_file_path(task.node.uuid)
+    for port in driver_utils.get_node_mac_addresses(task):
+        mac_path = get_pxe_mac_path(port)
+        utils.unlink_without_raise(mac_path)
+        utils.create_link_without_raise(pxe_config_file_path, mac_path)
+
+
+def build_pxe_config(node, pxe_options, pxe_config_template):
+    """Build the PXE config file for a node
+
+    This method builds the PXE boot configuration file for a node,
+    given all the required parameters.
+
+    :param pxe_options: A dict of values to set on the configuration file
+    :returns: A formatted string with the file content.
+    """
+    LOG.debug("Building PXE config for deployment %s."), node['id']
+
+    tmpl_path, tmpl_file = os.path.split(pxe_config_template)
+    env = jinja2.Environment(loader=jinja2.FileSystemLoader(tmpl_path))
+    template = env.get_template(tmpl_file)
+    return template.render({'pxe_options': pxe_options,
+                            'ROOT': '{{ ROOT }}'})
+
+
+def get_pxe_mac_path(mac):
+    """Convert a MAC address into a PXE config file name.
+
+    :param mac: A mac address string in the format xx:xx:xx:xx:xx:xx.
+    :returns: the path to the config file.
+    """
+    return os.path.join(
+        CONF.tftp.tftp_root,
+        'pxelinux.cfg',
+        "01-" + mac.replace(":", "-").lower()
+    )
+
+
+def get_pxe_config_file_path(node_uuid):
+    """Generate the path for an instances PXE config file."""
+    return os.path.join(CONF.tftp.tftp_root, node_uuid, 'config')
+
+
+def dhcp_options_for_instance(pxe_bootfile_name):
+    """Retrives the DHCP PXE boot options."""
+    return [{'opt_name': 'bootfile-name',
+             'opt_value': pxe_bootfile_name},
+            {'opt_name': 'server-ip-address',
+             'opt_value': CONF.tftp.tftp_server},
+            {'opt_name': 'tftp-server',
+             'opt_value': CONF.tftp.tftp_server}
+            ]