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Then the network needs at least one subnet; and the first subnet is created in the "subnet" pane. Give it a name, and select an IP range. It is recommended to use some RFC1918 adresses, which is not in use elsewhere in NTNU. The current official use of RFC1918 is:
- 10.0.0.0/8 - Used within NTNU, and is thus not recommended used in openstack networks.
- 172.16.0.0/16 - Used as floating-IP's in skyhigh.hig.no; free in other clouds
- 172.17.0.0/16 - Used within NTNU in Gjøvik, and is thus not recommended used in openstack networks.
- 172.18.0.0/15 - Free
- 172.20.0.0/14 - Free
- 172.24.0.0/13 - Free
- 192.168.0.0 - Partly used in NTNU Ålesund (subnets listed below). The rest is free.
- 192.168.10.0/24
- 192.168.30.0/24
- 192.168.50.0/24
- 192.168.90.0/24
- 192.168.110.0/24
- 192.168.114.0/24
- 192.168.201.0/24
- 192.168.212.0/24
- 192.168.221.0/24
- 192.168.222.0/24
- 192.168.223.0/24
- 192.168.224.0/24
See this article to see which addresses to select.
In this example the subnet "10.14.1.0/24" is used.
The final part of the network configuration dialog is to define additional DHCP parameters for any hosts placed in this network. The defaults (shown in the picture) is sufficient, but the following can be defined if wanted:
- Allocation pools: It is possible to limit which ranges of adresses in the subnet are used to address the virtual machines. The default is to use the whole pool; which should be fine in most cases.
- DNS Name Servers: If custom DNS Servers should be used for this subnet, their adresses should be listed here.
- Host Routes: If static routes (except for the regular default-route) should be injected to the hosts, they should be listed here.
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The network just created is currently isolated from the rest of the world. To give this network access to other networks, and the internet, we need to create a router. Navigate to "Network -> Routers" in the left menu, and click the "Create Router" button. Give the router a name, and select the network "ext-net" as the which external network this router should be connected to.
When the router is created, click on its name to start configuring it. We need to add an interface to the router, so click the "Add Interface" button.
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Select which network to allocate the floating IP from. At the time of writing there are only a single network available (ext-net), which is an RFC1918 network which is only available from inside the cloud environment.
When an IP is allocated, it can be Associated to a certain VM:
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