Networking Driver

This component is in charge of configuring the network in the hypervisors. The purpose of this guide is to describe how to create a new network manager driver.

Driver Configuration and Description

To enable a new network manager driver, the frist requirement is to make a new directory with the name of the driver in /var/lib/one/remotes/vnm/remotes/<name> with three files:

  • Pre: This driver should perform all the network related actions required before the Virtual Machine starts in a host.
  • Post: This driver should perform all the network related actions required after the Virtual Machine starts (actions which typically require the knowledge of the tap interface the Virtual Machine is connected to).
  • Clean: If any clean-up should be performed after the Virtual Machine shuts down, it should be placed here.

Warning

The above three files must exist. If no action is required in them a simple exit 0 will be enough.

Warning

Remember that any change in the /var/lib/one/remotes directory won’t be effective in the Hosts until you execute, as oneadmin: onehost sync -f

Virtual Machine actions and their relation with Network actions:

  • Deploy: pre and post
  • Shutdown: clean
  • Cancel: clean
  • Save: clean
  • Restore: pre and post
  • Migrate: pre (target host), clean (source host), post (target host)
  • Attach Nic: pre and post
  • Detach Nic: clean

After that you need to define the bridging technology used by the driver at /etc/one/oned.conf. OpenNebula support three differents technologies, Linux Bridge, Open vSwitch and vCenter Port Groups. See the examples below:

VN_MAD_CONF = [
    NAME = "vcenter"
    BRIDGE_TYPE = "vcenter_port_groups"
]

VN_MAD_CONF = [
    NAME = "ovswitch_vxlan"
    BRIDGE_TYPE = "openvswitch"
]

VN_MAD_CONF = [
    NAME = "bridge"
    BRIDGE_TYPE = "linux"
]

VN_MAD_CONF = [
    NAME = "custom"
    BRIDGE_TYPE = "none"
]

Note

Note that you can set BRIDGE_TYPE attribute to none if you need to leave the bridge empty.

Driver Customization

Default driver actions support the execution of hooks after the main action is succesfully executed. In order to create an action hook you need to place your custom configuration scripts in the corresponding action.d directory, inside the target networking driver directory. Files found in that directory will be run in an alphabetical order, excluding the ones oneadmin cannot run due to lack of permissions. If the main action fails the hooks won’t be run. If a hook fails the corresponding network actions will be consider as a FAILURE and the VM will change its state accordingly. Note that the scripts will receive the same information as the main action through stdin.

For example, this is the directory tree of the bridge driver synced to a virtualization node with some custom scripts

root@ubuntu1804-lxd-ssh-6ee11-2:/var/tmp/one/vnm/bridge# tree ./
./
├── clean
├── clean.d
│   ├── 01_del_fdb
│   ├── 02_del_routes
├── post
├── post.d
│   ├── 01_add_fdb
│   ├── 02_add_routes
├── pre
├── pre.d
│   ├── 01_update_router
└── update_sg

Driver Parameters

All three driver actions receive the XML VM template encoded in base64 format by stdin and a parameter which is the deploy-id of the Virtual Machine e.g.: one-17.

The clean action doesn’t require deploy-id

The 802.1Q Driver

Driver Files

The code can be enhanced and modified, by chaning the following files in the frontend:

  • /var/lib/one/remotes/vnm/802.1Q/post
  • /var/lib/one/remotes/vnm/802.1Q/vlan_tag_driver.rb
  • /var/lib/one/remotes/vnm/802.1Q/clean
  • /var/lib/one/remotes/vnm/802.1Q/pre

Driver Actions

Action Description
Pre Creates a VLAN tagged interface in the Host and a attaches it to a dynamically created bridge.
Post N/A
Clean It doesn’t do anything. The VLAN tagged interface and bridge are kept in the Host to speed up future VMs

The VXLAN Driver

Driver Files

The code can be enhanced and modified, by changing the following files in the frontend:

  • /var/lib/one/remotes/vnm/vxlan/vxlan_driver.rb
  • /var/lib/one/remotes/vnm/vxlan/post
  • /var/lib/one/remotes/vnm/vxlan/clean
  • /var/lib/one/remotes/vnm/vxlan/pre

Driver Actions

Action Description
Pre Creates a VXLAN interface through PHYDEV, creates a bridge (if needed) and attaches the vxlan device.
Post When the VM is associated to a security group, the corresponding iptables rules are applied.
Clean It doesn’t do anything. The VXLAN interface and bridge are kept in the Host to speed up future VMs

The Open vSwitch Driver

Driver Actions

Action Description
Pre N/A
Post Performs the appropriate Open vSwitch commands to tag the virtual tap interface.
Clean It doesn’t do anything. The virtual tap interfaces will be automatically discarded when the VM is shut down.

The ebtables Driver

Driver Actions

Action Description
Pre N/A
Post Creates EBTABLES rules in the Host where the VM has been placed.
Clean Removes the EBTABLES rules created during the Post action.