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Getting started with pot

For this guide, we assume that you have a FreeBSD 12+ machine, with a ZFS pool available.

Note

ZFS is mandatory, so if you don't know what it is or you don't have a ZFS pool, please consider to read this quick guide.

Install pot

pot is available as package or port. The suggested way is to install it using the packages:

# pkg install -y pot

Enable the resource accounting

The resource accounting, even if not mandatory for pot to run, is a suggested FreeBSD feature that can be used. This feature is still disabled by default on FreeBSD 12.x, and it can be enabled only at boot time.
To do so:

# echo kern.racct.enable=1 >> /boot/loader.conf
# reboot

Note

This settings will take effect ONLY after the next reboot.

Known issue

We have found a performance issue with the vtnet driver. If you are installing pot on a VM using vtnet, probably you want to add this line to your /boot/loader.conf:

# echo hw.vtnet.lro_disable=1 >> /boot/loader.conf

Note

This settings will take effect ONLY after the next reboot.

pot framework configuration

Under the folder /usr/local/etc/pot you'll find the files pot.conf.
The file configuration file has comments to with default values and explanations.

However, it's important to check if few defaults are compatible with your system:

  • POT_ZFS_ROOT : the name of the dataset where to put all pots (it will be created later)
  • POT_FS_ROOT : the mountpoint of the POT_ZFS_ROOT
  • POT_EXTIF : the network interface
  • POT_NETWORK : the IPv4 network that will be used for internal communication only (it must not overlap with your network setup)
  • POT_GATEWAY : an address consistent with the internal IPv4 network

For instance, as an example, those are alternative values that someone can use:

POT_ZFS_ROOT=zroot/potpool
POT_FS_ROOT=/var/potjails
POT_EXTIF=wlan0
POT_NETWORK=192.168.0.0/16
POT_GATEWAY=192.168.0.1

Network validation

If you want to run a naive check on the network side of your configuration, you can run:

# potnet config-check -v

Initialize the environment

When the configuration file is ready, you can now run the initialization.

Note

If you are already using pf, I suggest to make a backup of you pf configuration file.

To initialize, run the command (use the flag -v if you want a bit more of verbosity):

# cp /etc/pf.conf /etc/pf.conf.bak
# pot init -v

Create a simple pot

We can now create the simplest pot

# pot create -p mypot -t single -b 12.1

This command creates a pot named mypot based on FreeBSD 12.1 using one ZFS dataset (thick jail).

Now you can start/stop it, via:

# pot start mypot
# pot stop mypot
If you want to have a shell inside your pot:
# pot term mypot # when already running
# pot run mypot # an alias for start+term

If you want to get some information about your pot, you can:

# pot info -v -p mypot

Congratulations!

Congrats! You created your first jail using pot.
To learn more about the supported types of jails, you can read the documentation for Thin jails, Thick jails and Containers.


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