# How to set up OVN with LXD
See the following sections for how to set up a basic OVN network, either as a standalone network or to host a small LXD cluster.
## Set up a standalone OVN network
Complete the following steps to create a standalone OVN network that is connected to a managed LXD parent bridge network (for example, `lxdbr0`) for outbound connectivity.
1. Install the OVN tools on the local server:
```none
sudo apt install ovn-host ovn-central
```
2. Configure the OVN integration bridge:
```none
sudo ovs-vsctl set open_vswitch . \
external_ids:ovn-remote=unix:/var/run/ovn/ovnsb_db.sock \
external_ids:ovn-encap-type=geneve \
external_ids:ovn-encap-ip=127.0.0.1
```
3. Create an OVN network:
```none
lxc network set ipv4.dhcp.ranges= ipv4.ovn.ranges=
lxc network create ovntest --type=ovn network=
```
4. Create an instance that uses the `ovntest` network:
```none
lxc init ubuntu:24.04 c1
lxc config device override c1 eth0 network=ovntest
lxc start c1
```
5. Run [`lxc list`](https://canonical.com/lxd/docs/default/reference/manpages/lxc/list/index.html.md#lxc-list-md) to show the instance information:
`user@host:~$ ``lxc list`
```text
+------+---------+---------------------+----------------------------------------------+-----------+-----------+
| NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS |
+------+---------+---------------------+----------------------------------------------+-----------+-----------+
| c1 | RUNNING | 192.0.2.2 (eth0) | 2001:db8:cff3:5089:216:3eff:fef0:549f (eth0) | CONTAINER | 0 |
+------+---------+---------------------+----------------------------------------------+-----------+-----------+
```
## Set up a LXD cluster on OVN
▶
Watch on YouTube
Complete the following steps to set up a LXD cluster that uses an OVN network.
Just like LXD, the distributed database for OVN must be run on a cluster that consists of an odd number of members.
The following instructions use the minimum of three servers, which run both the distributed database for OVN and the OVN controller.
In addition, you can add any number of servers to the LXD cluster that run only the OVN controller.
See the linked YouTube video for the complete tutorial using four machines.
1. Complete the following steps on the three machines that you want to run the distributed database for OVN:
1. Install the OVN tools:
```none
sudo apt install ovn-central ovn-host
```
2. Mark the OVN services as enabled to ensure that they are started when the machine boots:
```none
systemctl enable ovn-central
systemctl enable ovn-host
```
3. Stop OVN for now:
```none
systemctl stop ovn-central
```
4. Note down the IP address of the machine:
```none
ip -4 a
```
5. Open `/etc/default/ovn-central` for editing.
6. Paste in one of the following configurations (replace ``, `` and `` with the IP addresses of the respective machines, and `` with the IP address of the machine that you are on).
- For the first machine:
```default
OVN_CTL_OPTS=" \
--db-nb-addr= \
--db-nb-create-insecure-remote=yes \
--db-sb-addr= \
--db-sb-create-insecure-remote=yes \
--db-nb-cluster-local-addr= \
--db-sb-cluster-local-addr= \
--ovn-northd-nb-db=tcp::6641,tcp::6641,tcp::6641 \
--ovn-northd-sb-db=tcp::6642,tcp::6642,tcp::6642"
```
- For the second and third machine:
```default
OVN_CTL_OPTS=" \
--db-nb-addr= \
--db-nb-cluster-remote-addr= \
--db-nb-create-insecure-remote=yes \
--db-sb-addr= \
--db-sb-cluster-remote-addr= \
--db-sb-create-insecure-remote=yes \
--db-nb-cluster-local-addr= \
--db-sb-cluster-local-addr= \
--ovn-northd-nb-db=tcp::6641,tcp::6641,tcp::6641 \
--ovn-northd-sb-db=tcp::6642,tcp::6642,tcp::6642"
```
7. Start OVN:
```none
systemctl start ovn-central
```
2. On the remaining machines, install only `ovn-host` and make sure it is enabled:
```none
sudo apt install ovn-host
systemctl enable ovn-host
```
3. On all machines, configure Open vSwitch (replace the variables as described above):
```none
sudo ovs-vsctl set open_vswitch . \
external_ids:ovn-remote=tcp::6642,tcp::6642,tcp::6642 \
external_ids:ovn-encap-type=geneve \
external_ids:ovn-encap-ip=
```
4. Create a LXD cluster by running `lxd init` on all machines.
On the first machine, create the cluster.
Then join the other machines with tokens by running [`lxc cluster add `](https://canonical.com/lxd/docs/default/reference/manpages/lxc/cluster/add/index.html.md#lxc-cluster-add-md) on the first machine and specifying the token when initializing LXD on the other machine.
5. On the first machine, create and configure the uplink network:
```none
lxc network create UPLINK --type=physical parent= --target=
lxc network create UPLINK --type=physical parent= --target=
lxc network create UPLINK --type=physical parent= --target=
lxc network create UPLINK --type=physical parent= --target=
lxc network create UPLINK --type=physical \
ipv4.ovn.ranges= \
ipv6.ovn.ranges= \
ipv4.gateway= \
ipv6.gateway= \
dns.nameservers=
```
To determine the required values:
Uplink interface
: A high availability OVN cluster requires a shared layer 2 network, so that the active OVN chassis can move between cluster members (which effectively allows the OVN router’s external IP to be reachable from a different host).
Therefore, you must specify either an unmanaged bridge interface or an unused physical interface as the parent for the physical network that is used for OVN uplink.
The instructions assume that you are using a manually created unmanaged bridge.
See [How to configure network bridges](https://netplan.readthedocs.io/en/stable/examples/#how-to-configure-network-bridges) for instructions on how to set up this bridge.
Gateway
: Run `ip -4 route show default` and `ip -6 route show default`.
Name server
: Run `resolvectl`.
IP ranges
: Use suitable IP ranges based on the assigned IPs.
6. Still on the first machine, configure LXD to be able to communicate with the OVN DB cluster.
To do so, find the value for `ovn-northd-nb-db` in `/etc/default/ovn-central` and provide it to LXD with the following command:
```none
lxc config set network.ovn.northbound_connection
```
#### NOTE
If you are using a MicroOVN deployment, pass the value of the MicroOVN node IP address you want to target. Prefix the IP address with `ssl:`, and suffix it with the `:6641` port number that corresponds to the OVN central service within MicroOVN.
7. Finally, create the actual OVN network (on the first machine):
```none
lxc network create my-ovn --type=ovn
```
8. To test the OVN network, create some instances and check the network connectivity:
```none
lxc launch ubuntu:24.04 c1 --network my-ovn
lxc launch ubuntu:24.04 c2 --network my-ovn
lxc launch ubuntu:24.04 c3 --network my-ovn
lxc launch ubuntu:24.04 c4 --network my-ovn
lxc list
lxc exec c4 -- bash
ping
ping
ping6 -n www.example.com
```
## Send OVN logs to LXD
Complete the following steps to have the OVN controller send its logs to LXD.
1. Enable the syslog socket:
```none
lxc config set core.syslog_socket=true
```
2. Open `/etc/default/ovn-host` for editing.
3. Paste the following configuration:
```none
OVN_CTL_OPTS=" \
--ovn-controller-log='-vsyslog:info --syslog-method=unix:/var/snap/lxd/common/lxd/syslog.socket'"
```
4. Restart the OVN controller:
```none
systemctl restart ovn-controller.service
```
You can now use [`lxc monitor`](https://canonical.com/lxd/docs/default/reference/manpages/lxc/monitor/index.html.md#lxc-monitor-md) to see logs from the OVN controller:
```none
lxc monitor --type=ovn
```
You can also send the logs to Loki.
To do so, add the `ovn` value to the [`loki.types`](https://canonical.com/lxd/docs/default/server/index.html.md#server-loki:loki.types) configuration key, for example:
```none
lxc config set loki.types=ovn
```
#### TIP
You can include logs for OVN `northd`, OVN north-bound `ovsdb-server`, and OVN south-bound `ovsdb-server` as well.
To do so, edit `/etc/default/ovn-central`:
```none
OVN_CTL_OPTS=" \
--ovn-northd-log='-vsyslog:info --syslog-method=unix:/var/snap/lxd/common/lxd/syslog.socket' \
--ovn-nb-log='-vsyslog:info --syslog-method=unix:/var/snap/lxd/common/lxd/syslog.socket' \
--ovn-sb-log='-vsyslog:info --syslog-method=unix:/var/snap/lxd/common/lxd/syslog.socket'"
sudo systemctl restart ovn-central.service
```