Fuel master node requirements are outdated

[Mike Scherbakov]

Following guide:
https://docs.mirantis.com/openstack/fuel/fuel-8.0/mos-planning-guide.html#sysreq-fuel-mn-hw-reqs

The problem is that since we switched to using upstream mirrors with packages for Ubuntu, and for maintenance updates, it is actually mandatory to have Internet access on fuel master node.
The problem is that in many cases your datacenter setup will have separate L2, which you'd use for PXEing your slave nodes, and separate network for Internet access.

Documentation has to reflect that operator has to have both network for PXE & Internet. If Datacenter setup is such that there is no Internet within PXE network, then Fuel Master node has to have two physical NICs (one for PXE, and one for Internet).
It is also possible to configure VLAN interfaces to be used on Fuel Master, however it will require manual and pretty complicated configuration of networking & Cobbler on Fuel master. Before it is automated or well documented, we need to require two physical interfaces for Fuel Master.

[Atsuko Ito (yottatsa)]

Let's define network topology as following:

VLAN 524: Admin (PXE), (unroutable, without internet access): 10.20.0.0/24
VLAN 525: Public (routable, with internet access), 172.16.16.32/27, gw: 172.16.16.33
VLANs 580-590 will be used for Management, Storage and Fixed.

Nodes (including Master node) are connected to the switch containing this two VLANs.
Port is configured as following: Trunk, Native VLAN: 524, Allowed VLAN 525,580-590.
In CISCO notation it will be like:

switchport mode trunk
switchport access vlan 524
switchport trunk allowed vlan 525,580-590

To bootstrap master node, customer will need to:

1. Boot it from CD (ISO)
2. Press Tab in the boot menu and change boot options according to routable network parameters (see attachment): vlan=eth0.525:eth0 and ip=....eth0.525.... (see https://bugzilla.redhat.com/show_bug.cgi?id=1276121)
3. Install Fuel Master
4. After installation, log in on Master node, configure eth0 in sysconfig and run bootstrap_admin_node.sh

[Bogdan Dobrelya (bogdando)]

Note, internal mirrors may work as well, so no Internet access is required, but info about internal mirrors how-to shall be provided