Table of Contents
CHPC Cloud Resources
Launching a VM instance
As a cloud end user, you can use the OpenStack dashboard to provision your own resources within the limits set by administrators. You can modify the examples provided in this section to create other types and sizes of server instances.
For your convenience, we offer these short instructions that you should follow in order to start a new instance, while also recommending you read the official user guide to familiarize with more advanced functionalities.
1. First please open https://sebowa.nicis.ac.za in your browser and login using the credentials provided.
2. Launching a virtual machine, You have to accomplish a number of steps.
a) Provide the initial hostname for the instance, the availability zone where it will be deployed, and the instance count. Increase the Count to create multiple instances with the same settings.:
b) Select the instance source, the template used to create an instance. You can use an image, a snapshot of an instance (image snapshot), a volume or a volume snapshot (if enabled). You can also choose to use persistent storage by creating a new volume.
For this example. The instance is launched from the image source and a new volume is created with the instance. The allocated ubuntu-18 image is selected from the list of available images and is going to be an Operating System (OS) for the instance/s created.
c) Decide on the flavor needed when launching the instance, Flavors manage the sizing for the compute, memory and storage capacity of the instance.
For this example. The instance is launched with m1.tiny flavor selected from the list of available flavors. The m1.tiny flavor will allocate the instance with 2x vCPU, 5GB of vRAM and 20GB of root disk. In order to carefully manage our compute resources, Only allocate what you are expecting to use, This is the total compute resources allocated to the instance created.
d) Select the network that your instance will connect to. The network provide the communication channels for instances in the cloud.
For this example. The instance is launched with demo-vxlan network selected from the list of available networks. The network provide the communication channel for instance/s in the cloud.
e) Select the security groups to launch the instance in.
For this example. The instance is launched with Default security group selected from the list of available security groups. The security groups are set of restrictive rules defined for the IP space, The selected default security group allows only ssh(22) and HTTPS(443). Openstack allows security groups editing after the instance has started, so additional changes can be made later if the exact requirements are not clearly defined.
f) Select an existing key pair, import a key pair, or generate a new key pair. A key pair allows you to SSH into your newly created instance.
g) Optionally, You can customize your instance after it has launched using the options available here. “Customization Script” is analogous to “User Data” in other systems.
h) Finally, click the Launch button. It will take a few minutes for the instance to start, depending on how large the base image you chose was, and if it was already cached or not on the physical server where the VM will be scheduled to start.
i) Associate a floating/public IP address.
By default, the VM will receive a private IP that is only reachable from inside your virtual network (other VMs connected to the same network). Because public IPv4 addresses are limited and there is an inherent security risk when connecting to the Internet, it is recommended to associate a floating/public IP address only to a single VM and use that one as an access server into your cloud environment.
How can I access the instance or virtual machine ?
1. OpenStack dashboard: Use console, double-click on the instance name you want to access and select the console tab. Use the login credential to access your instance if previously created and password authentication method enabled.
2. ssh into virtual machine: When you started the VM and specified the name of your key pair, its public part was automatically added to the default user’s “~/.ssh/authorized_keys” file, which will allow you SSH access into it.
From your laptop, first change the permissions for the private SSH key, so your SSH client doesn’t complain when you will try to use the key:
chmod 400 path_to_private_key
Then, using the desired SSH client application, run:
ssh -i path_to_private_key ubuntu@X.X.X.X
NB The X.X.X.X denotes to the IP address (use public IP allocated to the instance). ubuntu is the default username for ubuntu images and centos for CentOS images
3. Customize your virtual machine, upgrade the package index and existing packages, and it’s especially important to apply all the security updates available.
