Those who are aware of vCloud Director Installation and configuration, you would have noticed that two NICs or an IP alias are required to support two separate SSL connections on each vCloud Director cell server. One IP is used for the vCloud Director HTTP service and other is used for the console proxy service. When you try these methods, multiple NICs and IP aliasing, for the VCD cell server.
There is no unique feature that makes one method better than the other in terms of performance or other important metrics. Where both the http and the console proxy addresses are on the same subnet
To wrap some visualization around the two options, those not familiar with Linux IP Aliasing, you’d probably deploy each VCD cell server in a multihomed configured with a minimum of two NICs and two IP addresses required for VCD, one IP established for each of the required SSL connections.
The IP Alias method involves just a single NIC with two IP addresses on the same subnet sharing a common mask and default gateway for the two required SSL connections.
Without routed NFS on the network, each VCD cell server would have one additional NIC dedicated to an NFS network for vCloud Director Transfer Storage assuming the clustered cell configuration recommended for production and highly available cloud infrastructures.
Assuming that you have installed RHEL 5 Update 7 with a NIC having an IP address 192.168.0.10, adding an additional IP address via an alias takes just a few steps via CLI.
- Use nano -w /etc/sysconfig/network-scripts/ifcfg-eth0 to edit the network configuration for eth0. If it exists, remove the line GATEWAY=192.168.0.1 or comment it out by placing a hash (#) character at the beginning of the line like so: # GATEWAY=192.168.0.1 Save and exit nano with CTRL+X.
- Make a copy of ifcfg-eth0 to use for the IP alias. Do this with the command cp /etc/sysconfig/network-scripts/ifcfg-eth0/etc/sysconfig/network-scripts/ifcfg-eth0:0
- Use nano -w /etc/sysconfig/network-scripts/ifcfg-eth0:0 to edit the network configuration for eth0:0. Change DEVICE=eth0 to read DEVICE=eth0:0. Change IPADDR=192.168.0.10 to read IPADDR=192.168.0.11 Change ONBOOT=yes to read ONPARENT=yes Save and exit nano with CTRL+X.
- Use nano -w /etc/sysconfig/network to add a commonly shared default gateway for eth0 and eth0:0. Add the line GATEWAY=192.168.0.1 Save and exit nano with CTRL+X.
- Restart networking with service network restart.
At this point, the linux platform has single NIC with two IP addresses and the installation of vCloud Director on this cell can start.
The GUI approach obsoletes steps 1 and 4 from the CLI approach above. It removes the steps where the Default Gateway configuration is moved from the individual ifcfg-eth0 network startup scripts to the centralized /etc/sysconfig/network location. It further affirms the GATEWAY= entry may remain in each of the individual ifcfg-eth0 network startup scripts.
In the end, both methods work for a vCloud Director cell server however I imagine adding an additional NIC hard wired to an access port not on the 192.168.0.0 subnet will have issues with a GATEWAY=192.168.0.1 in /etc/sysconfig/network.
