The main idea of this new setup is to try and isolate services for the main host, which should be only used for management.

So every service will be run in it’s own context, known as jails in the Free/Net/OpenBSD lingua.

However a few helping services on the host might be usefull, for DNS resolving, log collection, …

Service IP

Since i don’t own a lot of IPv4 public adresses, some a private IPv4 network will be used for accessing services in this network familly, and some NAT will have to be set.

However online is being generous with IPv6 block so i can use a direct IPv6 connection.

To do so, i’ll use a dedicated loopback address, by adding the following to the rc.conf file:

cloned_interfaces="lo1"
ifconfig_lo1="up 10.0.2.1/24"
ifconfig_lo1_ipv6="inet6 2001:d8:1:101:0:0:1/64"

# setting syslog to listen on the internal loopback address and allowing inbound from the jail net:
syslogd_flags="-a 10.0.2.1/24 -b 10.0.2.1 -C"

The pf configuration from the previous post will have to be modified, to add so outbound NAT, and allow IPv6 outbound trafic for the jails:

# Define variable for jails networks
jail_net="10.0.2.0/24"
jail_net6="2001:d8:1:101::/64"

[...]

 # 4: Translation
 # Translate IPv4 adresses belonging to the private jail net on the public interface
 nat on $if from $jail_net to any -> $if

 # 5 Filtering
 # default outbound
 [...]
 # Allow ipv6 outbound packet from the jail ipv6 network
 pass out quick on $if from $jail_net6 to any

Reloading the pf configuration is done by :

r[email protected]:~ # pfctl -nf /etc/pf.conf

DNS Resolver

FreeBSD use the unbound resolver by default, by the default configuration won’t match our need. By default unbound will bind on 127.0.0.1:53 but we need him to listen on our jails ‘gateway’.

So we add a /etc/unbound/conf.d/interface.conf with the following content:

server:
        # Listen to loopback / jails loopback address
        interface: 127.0.0.1
        interface: 10.0.2.1
        interface: 2001:d8:1:101::1
        access-control: 10.0.0.0/8 allow
        access-control: 2001:bc8:1:100::/56 allow

This forces unbound to listen on all the IP addresses we need, and all dns query from the jails.

[email protected]:~ # service local_unbound restart

Setting-up EzJail

As i’m no FreeBSD expert, even a newbie, creating jails manually from scratch wasn’t an option i looked forward to ;) so in search to alternatives EzJail looked interesting, being integrated with ZFS and “space-friendly”.

EzJail works by initialising a shared “basejail” which is later on null-mounted (FreeBSD’s version of linux ‘bind’) in each jails /basejail directory. and a “newjail” directory which is the base template of all futur jails.

You can also use “flavours” to pre-set some files on the jails, be wary of the permissions of files and directory on thoses flavors however, they will be replicated on the jails !

My flavor for example automatically set the syslog.conf to log remotly on the host, the resolver, disable sendmail, etc …

A few options are necessary on the /usr/local/etc/ezjail.conf to activate the ZFS options:

# Setting this to YES will start to manage the basejail and newjail in ZFS
ezjail_use_zfs="YES"

# Setting this to YES will manage ALL new jails in their own zfs
ezjail_use_zfs_for_jails="YES"

# The name of the ZFS ezjail should create jails on, it will be mounted at the ezjail_jaildir
ezjail_jailzfs="zroot/ezjail"

Creating the first Jail

[email protected]:~ # ezjail-admin create ns3 'lo1|10.0.2.1,lo1|2001:d8:1:101::1'
/usr/jails/ns3/.
/usr/jails/ns3/./etc
/usr/jails/ns3/./etc/rc.conf
/usr/jails/ns3/./etc/rc.d
/usr/jails/ns3/./etc/rc.d/ezjail.mine
/usr/jails/ns3/./etc/periodic.conf
/usr/jails/ns3/./etc/syslog.conf
/usr/jails/ns3/./etc/resolv.conf
/usr/jails/ns3/./etc/crontab
8 blocks
find: /usr/jails/ns3/pkg/: No such file or directory
Warning: Some services already seem to be listening on all IP, (including 10.10.2.20)
  This may cause some confusion, here they are:
root     master     978   13 tcp4   *:25                  *:*
root     ntpd       884   20 udp6   *:123                 *:*
root     ntpd       884   21 udp4   *:123                 *:*
root     dhcp6c     770   4  udp6   *:546                 *:*
[email protected]:~ # ezjail-admin start ns3
[email protected]:~ # ezjail-admin console ns3
[email protected]:~ #

Enjoy your micro-vm/container/whatever ;)

Update from august:

Updating Jails

To the latest patch:

[email protected]:~ # ezjail-admin -u

Upgrading to the current host version (need to specify the ‘source’ version):

[email protected]:~ # ezjail-admin -U -s 11.0-RELEASE