Nebula Setup Instructions

Nebula is a cloud computing platform for research and development at the University of Arkansas. Learn more about Nebula and how to request access. 

To access Nebula, log into nebula.uark.edu with your UARK username and password. From off campus, connect to VPN first.

Create Access Key

  1. Click Access & Security. Click the Key Pairs tab and then click the + Create Key Pair button on the right.
  2. Enter a Key Pair Name.
    Recommended: yourusername-nebula
  3. Click Create Key Pair. The key pair will download as a .pem file. The key pair will be used to access your instances over SSH.

Create Instance

  1. Click Instances. Click the Launch Instance button on the right. 
  2. Enter an Instance Name. Click Next.
  3. Change the "Select Boot Source" option to Image.
  4. Change the "Delete Volume on Instance Delete" option to Yes.
  5. Choose an operating system by clicking the plus (+) button on the right. Click Next.
    Note: The default disk size is 10GB. This can be increased by changing the Volume Size field.
  6. Choose a VM Flavor by clicking the plus (+) button on the right.
    • Recommend m1.tiny for Ubuntu/Debian instances
    • Recommend m1.small for CentOS/RedHat instances
  7. Click Launch Instance. You will be returned to the Instances list. The status column will show Active when your instance has been set up.
  8. Click the Associate Floating IP button on the right.
  9. Select an IP Address and click Associate.

Access Instance

Before accessing an instance for the first time, Mac/Linux users will need to change the permissions of the key pair to read-only. Open Terminal and enter:

chmod 400 yourusername-nebula.pem

For Windows, Install Git and then open Git Bash from the Start menu. 

Connect to your instance using SSH in Terminal or Git Bash:

ssh -i yourusername-nebula.pem defaultusername@floatingip

  • Replace yourusername-nebula.pem with the key pair filename.
  • Replace defaultusername with the appropriate Default Username from the table below.
  • Replace floatingip with the IP address associated with the instance.
Instance OS Default Username
RedHat cloud-user
CentOS  centos
Ubuntu ubuntu
Debian debian

Network Ports

By default, instances respond to ICMP, TCP 22, TCP 80, TCP 443 and TCP 8887. Other ports can be added.

For example, to allow port 8080:

  1. Go to the Access & Security tab. Click  Security Groups.
  2. Click Manage Rules on the right.
  3. Click + Add Rule.
  4. Select Custom TCP Rule.
  5. Enter 8080 in the Port field.
  6. Click Add.

Updated 09/08/2017


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