[pve-docs.git] / pvesdn.adoc

[[chapter_pvesdn]]
Software Defined Network
========================
ifndef::manvolnum[]
:pve-toplevel:
endif::manvolnum[]

The **S**oftware **D**efined **N**etwork (SDN) feature allows one to create
virtual networks (vnets) at datacenter level.

WARNING: SDN is currently an **experimental feature** in {pve}. This
Documentation for it is also still under development, ask on our
xref:getting_help[mailing lists or in the forum] for questions and feedback.


[[pvesdn_installation]]
Installation
------------

To enable the experimental SDN integration, you need to install the
`libpve-network-perl` and `ifupdown2` package on every node:

----
apt update
apt install libpve-network-perl ifupdown2
----

After that you need to add the following line:

----
source /etc/network/interfaces.d/*
----
at the end of the `/etc/network/interfaces` configuration file, so that the SDN
config gets included and activated.


Basic Overview
--------------

The {pve} SDN allows separation and fine grained control of Virtual Guests
networks, using flexible software controlled configurations.

Separation consists of zones, a zone is it's own virtual separated network area.
A 'VNet' is a type of a virtual network connected to a zone. Depending on which
type or plugin the zone uses it can behave differently and offer different
features, advantages or disadvantages.
Normally a 'VNet' shows up as a common Linux bridge with either a VLAN or
'VXLAN' tag, but some can also use layer 3 routing for control.
The 'VNets' are deployed locally on each node, after configuration was committed
from the cluster-wide datacenter SDN administration interface.


Main configuration
~~~~~~~~~~~~~~~~~~

The configuration is done at datacenter (cluster-wide) level, it will be saved
in configuration files located in the shared configuration file system:
`/etc/pve/sdn`

On the web-interface  SDN feature have 3 main sections for the configuration

* SDN: a overview of the SDN state

* Zones: Create and manage the virtual separated network Zones

* VNets: Create virtual network bridges + subnets management.

And some options:

* Controller: For complex setups to control Layer 3 routing

* Sub-nets: Used to defined ip networks on VNets.

* IPAM: Allow to use external tools for IP address management (guest IPs)

* DNS: Allow to define a DNS server api for registering a virtual guests
  hostname and IP-addresses

[[pvesdn_config_main_sdn]]

SDN
~~~

This is the main status panel. Here you can see deployment status of zones on
different nodes.

There is an 'Apply' button, to push and reload local configuration on all
cluster nodes.


[[pvesdn_local_deployment_monitoring]]
Local Deployment Monitoring
~~~~~~~~~~~~~~~~~~~~~~~~~~~

After applying the configuration through the main SDN web-interface panel,
the local network configuration is generated locally on each node in
`/etc/network/interfaces.d/sdn`, and with ifupdown2 reloaded.

You can monitor the status of local zones and vnets through the main tree.


[[pvesdn_config_zone]]
Zones
-----

A zone will define a virtually separated network.

It can use different technologies for separation:

* VLAN: Virtual LANs are the classic method to sub-divide a LAN

* QinQ: stacked VLAN (formally known as `IEEE 802.1ad`)

* VXLAN: (layer2 vxlan)

* Simple: Isolated Bridge, simple l3 routing bridge (NAT)

* bgp-evpn: vxlan using layer3 border gateway protocol routing

You can restrict a zone to specific nodes.

It's also possible to add permissions on a zone, to restrict user to use only a
specific zone and only the VNets in that zone

Common options
~~~~~~~~~~~~~~

The following options are available for all zone types.

nodes:: Deploy and allow to use a VNets configured for this Zone only on these
nodes.

ipam:: Optional, if you want to use an ipam tool to manage ips in  this zone

dns:: Optional, dns api server.

reversedns:: Optional, reverse dns api server.

dnszone:: Optional, dns domain name. Use to register hostname like
`<hostname>.<domain>`. The dns zone need to be already existing in dns server.


[[pvesdn_zone_plugin_simple]]
Simple Zones
~~~~~~~~~~~~

This is the simplest plugin, it will create an isolated vnet bridge.
This bridge is not linked to physical interfaces, VM traffic is only
local to the node(s).
It can be also used for NAT or routed setup.

[[pvesdn_zone_plugin_vlan]]
VLAN Zones
~~~~~~~~~~

This plugin will reuse an existing local Linux or OVS bridge, 
and manage VLANs on it.
The benefit of using SDN module, is that you can create different zones with
specific VNets VLAN tag, and restrict Virtual Machines to separated zones.

Specific `VLAN` configuration options:

bridge:: Reuse this local bridge or OVS switch, already
configured on *each* local node.

[[pvesdn_zone_plugin_qinq]]
QinQ Zones
~~~~~~~~~~

QinQ is stacked VLAN. The first VLAN tag defined for the zone
(so called 'service-vlan'), and the second VLAN tag defined for the vnets

NOTE: Your physical network switches must support stacked VLANs!

Specific QinQ configuration options:

bridge:: A local VLAN-aware bridge already configured on each local node

service vlan:: The main VLAN tag of this zone

service vlan protocol:: allow to define a 802.1q (default) or 802.1ad service vlan type.

mtu:: Due to the double stacking of tags you need 4 more bytes for QinQ VLANs.
For example, you reduce the MTU to `1496` if you physical interface MTU is
`1500`.

[[pvesdn_zone_plugin_vxlan]]
VXLAN Zones
~~~~~~~~~~~

The VXLAN plugin will establish a tunnel (named overlay) on top of an existing
network (named underlay). It encapsulate layer 2 Ethernet frames within layer
4 UDP datagrams, using `4789` as the default destination port. You can, for
example, create a private IPv4 VXLAN network on top of public internet network
nodes.
This is a layer2 tunnel only, no routing between different VNets is possible.

Each VNet will have use specific VXLAN id from the range (1 - 16777215).

Specific EVPN configuration options:

peers address list:: A list of IPs from all nodes through which you want to
communicate. Can also be external nodes.

mtu:: Because VXLAN encapsulation use 50bytes, the MTU need to be 50 bytes
lower than the outgoing physical interface.

[[pvesdn_zone_plugin_evpn]]
EVPN Zones
~~~~~~~~~~

This is the most complex of all supported plugins.

BGP-EVPN allows one to create routable layer3 network. The VNet of EVPN can
have an anycast IP-address and or MAC-address. The bridge IP is the same on each
node, with this a virtual guest can use that address as gateway.

Routing can work across VNets from different zones through a VRF (Virtual
Routing and Forwarding) interface.

Specific EVPN configuration options:

VRF VXLAN tag:: This is a vxlan-id used for routing interconnect between vnets,
it must be different than VXLAN-id of VNets

controller:: an EVPN-controller need to be defined first (see controller
plugins section)

VNet MAC address:: A unique anycast MAC address for all VNets in this zone.
  Will be auto-generated if not defined.

Exit Nodes:: Optionnal. This is used if you want to define some proxmox nodes, as exit
  gateway from evpn network through real network. The configured nodes will
  announce a default route in the EVPN network.

Primary Exit Node:: Optionnal. If you use multiple exit-nodes, this force traffic 
  to a primary exit-node instead loadbalancing on all nodes.
  This is required if you want to use Snat or if your upstream router don't support
  ecmp.

Exit Nodes local routing:: Optional. This is a special option if you need to
  reach a vm/ct service from an exit node. (By default, the exit nodes only
  allow forwarding traffic between real network and evpn network).

Advertise Subnets:: Optional. If you have silent vms/CT (for example, multiples
  ips by interfaces, and the anycast gateway don't see traffic from theses ips,
  the ips addresses won't be able to be reach inside the evpn network). This
  option will announce the full subnet in the evpn network in this case.

Disable Arp-Nd Suppression:: Optional. Don't suppression arp or nd packets.
  This is required if you use moving virtual ip in your guests vm. 
  (Ip is moving but mac address change)

Route-target import:: Optional. Allow to import a list of external evpn route-targets.
  For Cross-DC or differents evpn networks interconnect.

MTU:: because VXLAN encapsulation use 50 bytes, the MTU needs to be 50 bytes
  lower than the maximal MTU of the outgoing physical interface.


[[pvesdn_config_vnet]]
VNets
-----

A `VNet` is in its basic form just a Linux bridge that will be deployed locally
on the node and used for Virtual Machine communication.

VNet properties are:

ID:: a 8 characters ID to name and identify a VNet

Alias:: Optional longer name, if the ID isn't enough

Zone:: The associated zone for this VNet

Tag:: The unique VLAN or VXLAN id

VLAN Aware:: Allow to add an extra VLAN tag in the virtual machine or
  container vNIC configurations or allow the guest OS to manage the VLAN's tag.

[[pvesdn_config_subnet]]

Sub-Nets
~~~~~~~~

A sub-network (subnet or sub-net) allows you to define a specific IP network
(IPv4 or IPv6). For each VNET, you can define one or more subnets.

A subnet can be used to:

* restrict IP-addresses you can define on a specific VNET
* assign routes/gateway on a VNET in layer 3 zones
* enable SNAT on a VNET in layer 3 zones
* auto assign IPs on virtual guests (VM or CT) through IPAM plugin
* DNS registration through DNS plugins

If an IPAM server is associated to the subnet zone, the subnet prefix will be
automatically registered in the IPAM.


Subnet properties are:

ID:: a cidr network address. Ex: 10.0.0.0/8

Gateway:: ip address for the default gateway of the network. 
          On layer3 zones (simple/evpn plugins), it'll be deployed on the vnet.

Snat:: Optional, Enable Snat for layer3 zones (simple/evpn plugins) for this subnet.
       The subnet source ip will be natted to server outgoing interface/ip.
       On evpn zone, it's done only on evpn gateway-nodes.

Dnszoneprefix:: Optional, add a prefix to domain registration, like <hostname>.prefix.<domain>


[[pvesdn_config_controllers]]
Controllers
-----------

Some zone types need an external controller to manage the VNet control-plane.
Currently this is only required for the `bgp-evpn` zone plugin.

[[pvesdn_controller_plugin_evpn]]
EVPN Controller
~~~~~~~~~~~~~~~

For `BGP-EVPN`, we need a controller to manage the control plane.
The currently supported software controller is the "frr" router.
You may need to install it on each node where you want to deploy EVPN zones.

----
apt install frr frr-pythontools
----

Configuration options:

asn:: A unique BGP ASN number. It's highly recommended to use private ASN
number (64512 – 65534, 4200000000 – 4294967294), as else you could end up
breaking, or get broken, by global routing by mistake.

peers:: An ip list of all nodes where you want to communicate for the EVPN (could be also
external nodes or route reflectors servers)


[[pvesdn_controller_plugin_BGP]]
BGP Controller
~~~~~~~~~~~~~~~

The bgp controller is not used directly by a zone. 
You can used it to configure frr to manage bgp peers.

For BGP-evpn, it can be use to define a different ASN by node, so doing EBGP.

Configuration options:

node:: The node of this BGP controller

asn:: A unique BGP ASN number. It's highly recommended to use private ASN
  number from the range (64512 - 65534) or (4200000000 - 4294967294), as else
  you could end up breaking, or get broken, by global routing by mistake.

peers:: An IP list of peers you want to communicate with for the underlying
  BGP network.

ebgp:: If your peer's remote-AS is different, it's enabling EBGP.

loopback:: If you want to use a loopback or dummy interface as source for the
  evpn network. (for multipath)

ebgp-mutltihop:: if the peers are not directly connected or use loopback, you can increase the
  number of hops to reach them.

bgp-multipath-as-path-relax:: Allow to do ECMP if your peers have differents ASN.

[[pvesdn_config_ipam]]
IPAMs
-----
IPAM (IP address management) tools, are used to manage/assign ips on your devices on the network.
It can be used to find free ip address when you create a vm/ct for example (not yet implemented).

An IPAM is associated to 1 or multiple zones, to provide ip addresses for all subnets defined in this zone.


[[pvesdn_ipam_plugin_pveipam]]
{pve} IPAM plugin
~~~~~~~~~~~~~~~~~

This is the default internal IPAM for your proxmox cluster if you don't have
external ipam software

[[pvesdn_ipam_plugin_phpipam]]
phpIPAM plugin
~~~~~~~~~~~~~~
https://phpipam.net/

You need to create an application in phpipam, and add an api token with admin
permission

phpIPAM properties are:

url:: The REST-API endpoint: `http://phpipam.domain.com/api/<appname>/`
token:: An API access token
section:: An integer ID. Sections are group of subnets in phpIPAM. Default
 installations use `sectionid=1` for customers.

[[pvesdn_ipam_plugin_netbox]]
Netbox IPAM plugin
~~~~~~~~~~~~~~~~~~

NetBox is an IP address management (IPAM) and data center infrastructure
management (DCIM) tool, see the source code repository for details:
https://github.com/netbox-community/netbox

You need to create an api token in netbox
https://netbox.readthedocs.io/en/stable/api/authentication

NetBox properties are:

url:: The REST API endpoint: `http://yournetbox.domain.com/api`
token:: An API access token

[[pvesdn_config_dns]]
DNS
---

The DNS plugin in {pve} SDN is used to define a DNS API server for registration
of your hostname and IP-address. A DNS configuration is associated with one or
more zones, to provide DNS registration for all the sub-net IPs configured for
a zone.

[[pvesdn_dns_plugin_powerdns]]
PowerDNS plugin
~~~~~~~~~~~~~~~
https://doc.powerdns.com/authoritative/http-api/index.html

You need to enable the webserver and the API in your PowerDNS config:

----
api=yes
api-key=arandomgeneratedstring
webserver=yes
webserver-port=8081
----

Powerdns properties are:

url:: The REST API endpoint: http://yourpowerdnserver.domain.com:8081/api/v1/servers/localhost
key:: An API access key
ttl:: The default TTL for records


Examples
--------

[[pvesdn_setup_example_vlan]]
VLAN Setup Example
~~~~~~~~~~~~~~~~~~

TIP: While we show plain configuration content here, almost everything should
be configurable using the web-interface only.

Node1: /etc/network/interfaces

----
auto vmbr0
iface vmbr0 inet manual
	bridge-ports eno1
	bridge-stp off
	bridge-fd 0
	bridge-vlan-aware yes
	bridge-vids 2-4094

#management ip on vlan100
auto vmbr0.100
iface vmbr0.100 inet static
	address 192.168.0.1/24

source /etc/network/interfaces.d/*
----

Node2: /etc/network/interfaces

----
auto vmbr0
iface vmbr0 inet manual
	bridge-ports eno1
	bridge-stp off
	bridge-fd 0
	bridge-vlan-aware yes
	bridge-vids 2-4094

#management ip on vlan100
auto vmbr0.100
iface vmbr0.100 inet static
	address 192.168.0.2/24

source /etc/network/interfaces.d/*
----

Create a VLAN zone named `myvlanzone':

----
id: myvlanzone
bridge: vmbr0
----

Create a VNet named `myvnet1' with `vlan-id` `10' and the previously created
`myvlanzone' as it's zone.

----
id: myvnet1
zone: myvlanzone
tag: 10
----

Apply the configuration through the main SDN panel, to create VNets locally on
each nodes.

Create a Debian-based Virtual Machine (vm1) on node1, with a vNIC on `myvnet1'.

Use the following network configuration for this VM:

----
auto eth0
iface eth0 inet static
	address 10.0.3.100/24
----

Create a second Virtual Machine (vm2) on node2, with a vNIC on the same VNet
`myvnet1' as vm1.

Use the following network configuration for this VM:

----
auto eth0
iface eth0 inet static
	address 10.0.3.101/24
----

Then, you should be able to ping between both VMs over that network.


[[pvesdn_setup_example_qinq]]
QinQ Setup Example
~~~~~~~~~~~~~~~~~~

TIP: While we show plain configuration content here, almost everything should
be configurable using the web-interface only.

Node1: /etc/network/interfaces

----
auto vmbr0
iface vmbr0 inet manual
	bridge-ports eno1
	bridge-stp off
	bridge-fd 0
	bridge-vlan-aware yes
	bridge-vids 2-4094

#management ip on vlan100
auto vmbr0.100
iface vmbr0.100 inet static
	address 192.168.0.1/24

source /etc/network/interfaces.d/*
----

Node2: /etc/network/interfaces

----
auto vmbr0
iface vmbr0 inet manual
	bridge-ports eno1
	bridge-stp off
	bridge-fd 0
	bridge-vlan-aware yes
	bridge-vids 2-4094

#management ip on vlan100
auto vmbr0.100
iface vmbr0.100 inet static
	address 192.168.0.2/24

source /etc/network/interfaces.d/*
----

Create an QinQ zone named `qinqzone1' with service VLAN 20

----
id: qinqzone1
bridge: vmbr0
service vlan: 20
----

Create another QinQ zone named `qinqzone2' with service VLAN 30

----
id: qinqzone2
bridge: vmbr0
service vlan: 30
----

Create a VNet named `myvnet1' with customer vlan-id 100 on the previously
created `qinqzone1' zone.

----
id: myvnet1
zone: qinqzone1
tag: 100
----

Create a `myvnet2' with customer VLAN-id 100 on the previously created
`qinqzone2' zone.

----
id: myvnet2
zone: qinqzone2
tag: 100
----

Apply the configuration on the main SDN web-interface panel to create VNets
locally on each nodes.

Create a Debian-based Virtual Machine (vm1) on node1, with a vNIC on `myvnet1'.

Use the following network configuration for this VM:

----
auto eth0
iface eth0 inet static
        address 10.0.3.100/24
----

Create a second Virtual Machine (vm2) on node2, with a vNIC on the same VNet
`myvnet1' as vm1.

Use the following network configuration for this VM:

----
auto eth0
iface eth0 inet static
        address 10.0.3.101/24
----

Create a third Virtual Machine (vm3) on node1, with a vNIC on the other VNet
`myvnet2'.

Use the following network configuration for this VM:

----
auto eth0
iface eth0 inet static
        address 10.0.3.102/24
----

Create another Virtual Machine (vm4) on node2, with a vNIC on the same VNet
`myvnet2' as vm3.

Use the following network configuration for this VM:

----
auto eth0
iface eth0 inet static
        address 10.0.3.103/24
----

Then, you should be able to ping between the VMs 'vm1' and 'vm2', also
between 'vm3' and 'vm4'. But, none of VMs 'vm1' or 'vm2' can ping the VMs 'vm3'
or 'vm4', as they are on a different zone with different service-vlan.


[[pvesdn_setup_example_vxlan]]
VXLAN Setup Example
~~~~~~~~~~~~~~~~~~~

TIP: While we show plain configuration content here, almost everything should
be configurable using the web-interface only.

node1: /etc/network/interfaces

----
auto vmbr0
iface vmbr0 inet static
	address 192.168.0.1/24
	gateway 192.168.0.254
	bridge-ports eno1
	bridge-stp off
	bridge-fd 0
	mtu 1500

source /etc/network/interfaces.d/*
----

node2: /etc/network/interfaces

----
auto vmbr0
iface vmbr0 inet static
	address 192.168.0.2/24
	gateway 192.168.0.254
	bridge-ports eno1
	bridge-stp off
	bridge-fd 0
	mtu 1500

source /etc/network/interfaces.d/*
----

node3: /etc/network/interfaces

----
auto vmbr0
iface vmbr0 inet static
	address 192.168.0.3/24
	gateway 192.168.0.254
	bridge-ports eno1
	bridge-stp off
	bridge-fd 0
	mtu 1500

source /etc/network/interfaces.d/*
----

Create an VXLAN zone named `myvxlanzone', use the lower MTU to ensure the extra
50 bytes of the VXLAN header can fit. Add all previously configured IPs from
the nodes as peer address list.

----
id: myvxlanzone
peers address list: 192.168.0.1,192.168.0.2,192.168.0.3
mtu: 1450
----

Create a VNet named `myvnet1' using the VXLAN zone `myvxlanzone' created
previously.

----
id: myvnet1
zone: myvxlanzone
tag: 100000
----

Apply the configuration on the main SDN web-interface panel to create VNets
locally on each nodes.

Create a Debian-based Virtual Machine (vm1) on node1, with a vNIC on `myvnet1'.

Use the following network configuration for this VM, note the lower MTU here.

----
auto eth0
iface eth0 inet static
        address 10.0.3.100/24
        mtu 1450
----

Create a second Virtual Machine (vm2) on node3, with a vNIC on the same VNet
`myvnet1' as vm1.

Use the following network configuration for this VM:

----
auto eth0
iface eth0 inet static
        address 10.0.3.101/24
        mtu 1450
----

Then, you should be able to ping between between 'vm1' and 'vm2'.


[[pvesdn_setup_example_evpn]]
EVPN Setup Example
~~~~~~~~~~~~~~~~~~

node1: /etc/network/interfaces

----
auto vmbr0
iface vmbr0 inet static
	address 192.168.0.1/24
	gateway 192.168.0.254
        bridge-ports eno1
        bridge-stp off
        bridge-fd 0
	mtu 1500

source /etc/network/interfaces.d/*
----

node2: /etc/network/interfaces

----
auto vmbr0
iface vmbr0 inet static
	address 192.168.0.2/24
	gateway 192.168.0.254
        bridge-ports eno1
        bridge-stp off
        bridge-fd 0
	mtu 1500

source /etc/network/interfaces.d/*
----

node3: /etc/network/interfaces

----
auto vmbr0
iface vmbr0 inet static
	address 192.168.0.3/24
	gateway 192.168.0.254
        bridge-ports eno1
        bridge-stp off
        bridge-fd 0
	mtu 1500

source /etc/network/interfaces.d/*
----

Create a EVPN controller, using a private ASN number and above node addreesses
as peers.

----
id: myevpnctl
asn: 65000
peers: 192.168.0.1,192.168.0.2,192.168.0.3
----

Create an EVPN zone named `myevpnzone' using the previously created
EVPN-controller Define 'node1' and 'node2' as exit nodes.

----
id: myevpnzone
vrf vxlan tag: 10000
controller: myevpnctl
mtu: 1450
vnet mac address: 32:F4:05:FE:6C:0A
exitnodes: node1,node2
----

Create the first VNet named `myvnet1' using the EVPN zone `myevpnzone'.
----
id: myvnet1
zone: myevpnzone
tag: 11000
----

Create a subnet 10.0.1.0/24 with 10.0.1.1 as gateway on vnet1

----
subnet: 10.0.1.0/24
gateway: 10.0.1.1
----

Create the second VNet named `myvnet2' using the same EVPN zone `myevpnzone', a
different IPv4 CIDR network.

----
id: myvnet2
zone: myevpnzone
tag: 12000
----

Create a different subnet 10.0.2.0/24 with 10.0.2.1 as gateway on vnet2

----
subnet: 10.0.2.0/24
gateway: 10.0.2.1
----


Apply the configuration on the main SDN web-interface panel to create VNets
locally on each nodes and generate the FRR config.

Create a Debian-based Virtual Machine (vm1) on node1, with a vNIC on `myvnet1'.

Use the following network configuration for this VM:

----
auto eth0
iface eth0 inet static
        address 10.0.1.100/24
        gateway 10.0.1.1   #this is the ip of the vnet1 
        mtu 1450
----

Create a second Virtual Machine (vm2) on node2, with a vNIC on the other VNet
`myvnet2'.

Use the following network configuration for this VM:

----
auto eth0
iface eth0 inet static
        address 10.0.2.100/24
        gateway 10.0.2.1   #this is the ip of the vnet2
        mtu 1450
----


Then, you should be able to ping vm2 from vm1, and vm1 from vm2.

If you ping an external IP from 'vm2' on the non-gateway 'node3', the packet
will go to the configured 'myvnet2' gateway, then will be routed to the exit
nodes ('node1' or 'node2') and from there it will leave those nodes over the
default gateway configured on node1 or node2.

NOTE: Of course you need to add reverse routes for the '10.0.1.0/24' and
'10.0.2.0/24' network to node1, node2 on your external gateway, so that the
public network can reply back.

If you have configured an external BGP router, the BGP-EVPN routes (10.0.1.0/24
and 10.0.2.0/24 in this example), will be announced dynamically.


Notes
-----

VXLAN IPSEC Encryption
~~~~~~~~~~~~~~~~~~~~~~
If you need to add encryption on top of VXLAN, it's possible to do so with
IPSEC through `strongswan`. You'll need to reduce the 'MTU' by 60 bytes (IPv4)
or 80 bytes (IPv6) to handle encryption.

So with default real 1500 MTU, you need to use a MTU of 1370 (1370 + 80 (IPSEC)
+ 50 (VXLAN) == 1500).

.Install strongswan
----
apt install strongswan
----

Add configuration in `/etc/ipsec.conf'. We only need to encrypt traffic from
the VXLAN UDP port '4789'.

----
conn %default
    ike=aes256-sha1-modp1024!  # the fastest, but reasonably secure cipher on modern HW
    esp=aes256-sha1!
    leftfirewall=yes           # this is necessary when using Proxmox VE firewall rules

conn output
    rightsubnet=%dynamic[udp/4789]
    right=%any
    type=transport
    authby=psk
    auto=route

conn input
    leftsubnet=%dynamic[udp/4789]
    type=transport
    authby=psk
    auto=route
----

Then generate a preshared key with

----
openssl rand -base64 128
----

and copy the key in `/etc/ipsec.secrets' so that the file content looks like:

----
: PSK <generatedbase64key>
----

You need to copy the PSK and the config on other nodes.