...
Click on "+ Create Network" and fill in the fields. They should be:
- Network
- Name: Similar to your master's name, so that it's easy to match them.
- Create Subnet: checked
- Subnet
- Subnet Name: can be the same name as the network, doesn't matter
- Network address: can be anything different from your main network, ex. 172.22.16.0/24. It's good to keep it different from the other internal networks.
- Gateway IP: is the IP of the master on the internal network, usually x.x.x.1
- Disable Gateway: checked. This should avoid the network associating a non-1 IP to the master's internal NIC
- Subnet details
- Enable DHCP: disabled
- Everything else empty
Creating a Master Instance
On the "Instances" tab, click on "Launch Instance" and fill in the fields. They should be:
- Details
- Name: a personalised name, with the SSH pattern above (ex. ohpc-master-yourname)
- Source
- Choose the CentOS 7 image (centos7-cloud) [1]
- Flavour
- You'll need at least 10GB of disk and 2 cores
- Networks
- Be careful, here's the trick: First move the internal network, then the main one. [2]
[1] The master instance needs to be either CentOS 7 or SLES 12. For now, we only have CentOS images, so choose that one.
[2] The order matters, because QEMU has trouble adding the interfaces. The first NIC will connect to the second network and vice-versa, and only the first network has DHCP set.
Everything else is irrelevant, just click "Launch Instance".