How to map static IP address using dnsmasq under LXD (Linux containers)

To map a static IP address to a container using dnsmasq under LXD (Linux containers), you will need to do the following:

1. Install dnsmasq on the host system. You will need to install dnsmasq on the host system that is running LXD. You can install dnsmasq using the package manager for your Linux distribution (e.g., apt, yum, pacman).

For example, on a Debian-based system, you can use the following command to install dnsmasq:

$ sudo apt-get install dnsmasq

2. Edit the dnsmasq configuration file. You will need to edit the dnsmasq configuration file (usually /etc/dnsmasq.conf) to specify the static IP mapping for the container.

To specify the static IP mapping, you will need to add a line to the configuration file with the following format:

dhcp-host=<MAC address>,<IP address>

Replace <MAC address> with the MAC address of the container's network interface and <IP address> with the static IP address that you want to assign to the container.

For example, to map the static IP address 10.0.0.100 to the container with the MAC address 00:11:22:33:44:55, you would add the following line to the dnsmasq configuration file:

dhcp-host=00:11:22:33:44:55,10.0.0.100

3. Restart the dnsmasq service. After you have edited the dnsmasq configuration file, you will need to restart the dnsmasq service to apply the changes. You can use the service or systemctl command to restart the dnsmasq service, depending on your Linux distribution.

For example, on a Debian-based system, you can use the following command to restart the dnsmasq service:

$ sudo service dnsmasq restart

On a Red Hat-based system, you can use the following command to restart the dnsmasq service:

$ sudo systemctl restart dnsmasq

4. Configure the container's network settings. In the container, you will need to configure the network settings to use a static IP address. You can do this by editing the /etc/network/interfaces file and adding a static block for the network interface.

For example, to configure the eth0 interface with the static IP address 10.0.0.100, you would add the following lines to the /etc/network/interfaces file:

auto eth0
iface eth0 inet static
    address 10.0.0.100
    netmask 255.255.255.0
    gateway 10.0.0.1

5. Restart the container's network. After you have edited the /etc/network/interfaces file, you will need to restart the container's network to apply the changes. You can do this by running the ifdown and ifup commands for the network interface.

For example, to restart the eth0 interface, you can use the following commands:

$ ifdown eth0
$ if