IPtables in Vagrant setup - Worker

[DailyAlice]

There was a request for docs surrounding iptables on a Worker post-Vagrant set up.

Need to follow-up with @Cbkhare, @gianarb, or @dan to get the details.

[thebsdbox]

The issue that we face is that whilst a machine/laptop may be internet facing, the virtual machines created by Vagrant are not.

   +--------------+
   |   Internet   |
   +------+-------+
          |
+--------------------------------------------+
|         |                                  |
|  +------+-----+       +--------------+     |
|  |    eth0    |       |  Tinkerbell  |     |
|  +------------+       +-+------------+     |
|                         |                  |
+--------------------------------------------+
                          |
                    +-----v-----+
                    |    VM1    |
                    +-----------+

In order to provide this functionality to these created virtual machines we need to use iptables to allow ip_forwarding and network address translation from the network traffic of VM1 to traverse eth0

# Set the environment variables of the two interfaces
export main=<public_ip_iface>
export vagrant=<tinkerbell_ip_iface> 

# Enable internet forwarding (not permanent, we would need to edit /etc/sysctl for this)
echo 1 > /proc/sys/net/ipv4/ip_forward

# Forward traffic from vagrant network to main interface
iptables -A FORWARD -i $vagrant -o $main -j ACCEPT

# Forward established (existing traffic back from internet to vagrant network
iptables -A FORWARD -i $main -o $vagrant -m state --state ESTABLISHED,RELATED \
         -j ACCEPT

# Translate addresses so traffic appears to have come from the correct address
iptables -t nat -A POSTROUTING -o $vagrant -j MASQUERADE

   +--------------+
   |   Internet   |
   +------+-------+
          |
+----------------------------------------------------+
|         |                                          |
|  +------+---+---------------------->+------------+ |
|  |    eth0  |       iptables        | Tinkerbell | |
|  +----------+<----------------------+--------+---+ |
|                                              |     |
+----------------------------------------------------+
                                               |
                                           +---v---+
                                           |  VM1  |
                                           +-------+

[DailyAlice]

@thebsdbox does this issue affect both the Provisioner and the Worker? I think this originally discussed in context of letting a Worker see the Internet, but if it does also affect the Provisioner are there any cases where you would want to run the commands there too?

Edit: I think the diagrams answer my question, since the Provisioner is providing the network interface to the Worker, it does not have the same problem.

[DailyAlice]

Other thoughts - I can just drop in this content at the end of the Vagrant set up doc, but is there any context on why someone would want or need to have the Worker see the Internet at this point? @thebsdbox