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Configure the network

tip

If you are using a wired connection, you can skip this and jump straight to the "Containerd" section.

With a wired connection, flintlock will be able to create macvtap devices for its MicroVMs. This needs to be enabled in your kernel: check with modprobe macvlan. If this returns non-zero, either install the extra headers or config, or continue with this page to use tap interfaces instead.

If your machine is not on ethernet right now, you will need to set up a local bridge (virtual router).

We recommend using a dedicated network to avoid interference from other kvm machines or things like IP or MAC address conflict.

Install packages and start libvirtd​

sudo apt install qemu qemu-kvm libvirt-clients libvirt-daemon-system virtinst bridge-utils

sudo systemctl enable libvirtd
sudo systemctl start libvirtd

Create kvm network​

Create a file with the network config. Feel free to change the IP range if it conflicts with any existing network config you have:

BRIDGE=flbr0
cat << EOF >flintlock-net.xml
<network>
  <name>flintlock</name>
  <forward mode='nat'>
    <nat>
      <port start='1024' end='65535'/>
    </nat>
  </forward>
  <bridge name="$BRIDGE" stp='on' delay='0'/>
  <ip address='192.168.100.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.100.10' end='192.168.100.254'/>
    </dhcp>
  </ip>
</network>
EOF

Define and start the new network:

sudo virsh net-define flintlock.xml
sudo virsh net-start flintlock

If you wish, you can also set it to autostart on boot:

sudo virsh net-autostart flintlock

You should see the network in the network list:

virsh net-list
 Name       State    Autostart   Persistent
---------------------------------------------
 default    active   yes         yes
 flintlock   active   yes         yes

Create and connect tap device​

Create a new tap (port) from the bridge to your machine's default interface.

TAPNAME=tap0

sudo ip tuntap add ${TAPNAME} mode tap
sudo ip link set ${TAPNAME} master ${BRIDGE} up

Check with ip link ls.

When MicroVMs are created, they will come up in this virtual network and will request an IP from the DHCP server configured in the network file above. You will be able to check the DHCP leases with virsh:

sudo virsh net-dhcp-leases default