OpenStack Introduction

Login

• Go to https://julia.uni-wuerzburg.de
• Use your JMU account credentials
• Use domain: julia

Launch a virtual machine

• Go to: Project -> Compute -> Instances
• Click: "Launch Instance"

Virtual machine setup

In order to start a virtual machine, you have to fill out the required fields in the following whizzard. These fields are marked with an asterisk (*).

Details

• Give your machine an Instance Name like: myProjectName. With that name, you can later easily identify your machine in the list of all running machines.
• Define the number of machines, you want to create. The default Count is 1.

Source

You will be given a list of operating systems. We provide operating system images ending with the "-Julia" suffix, like

• Ubuntu16.04-Julia
• Ubuntu18.04-Julia
• Debian9-Julia

Select your operating system by clicking on the "Up" arrow button.

Flavor

Now you can select the properties of your machine like numbers of CPU cores and memory. These properties are defined as flavors.

Name	RAM	VCPUs
tiny	4096	2
small	8192	4
medium	16384	8
large	184320	16
xlarge	368640	32

Some other flavors are special:

Name	RAM	VCPUs	Comment
gpu.large	180000	16	Will spawn on a GPU node with one dedicated GPU accelerator card
fat.huge	1024000	72	Will spawn on a FAT node and provide up to 1TB of RAM

Select your flavor by clicking on the "Up" arrow button.

Key Pair

In order to login to your machine after sucessfully launching the virtual machine, you have to provide an SSH public key. If not done already, you can either upload the public key from your local machine or create a new one. Otherwise just select one of your uploaded public keys.

Access to your machine

You can access your virtual machine via an special IP address, known as Floating IP.

On the Compute -> Instances page find your machine and click on "Associate Floating IP" in the dropdown menu on the right side of the webpage.

In the following whizzard you can select your favorite Floating IP from the dropdown menu.

If the list of available IPs is empty, feel free to click on the "Plus" button to request additional IPs. You can then select the new requested IP in the dropdown menu.

As you can see, the Floating IPs are in the range from 10.106.241.1 to 10.106.250.254. These private IP addresses are routet inside of the univerity network. If you are at home or are using some other WLAN except RZUWsec, you may need a VPN connection to connect to the university network first.

Login via SSH

Now you are able to login via SSH to your machine by using the Floating IP, you selected. e.g.

$ ssh debian@10.106.241.65
Linux myprojectname 4.9.0-6-amd64 #1 SMP Debian 4.9.88-1+deb9u1 (2018-05-07) x86_64


Welcome to Julia Computing Environment

debian@myprojectname:~$ 

For our provided operating systems the default user for Ubuntu based systesms is ubuntu and debian for Debian based systems.

Install your software environment

You can use sudo to gain administrative rights in order to install software and configure your virtual machine:

debian@myprojectname:~$ sudo su -
myprojectname debian $ whoami
root
myprojectname debian $ 

Finalizing your virtual machine

Create a snapshot

After finishing the installation of your software environment you should shutdown your machine. Create a snapshot afterwards by using "Create Snapshot" in the dropdown menu on the instances overview page and give the snapshot a meaningfull name.

The snapshot can be used to spawn new virtual machines with that exact image of your software environment.

Select "Snapshot" in the dropdown menu in the "Source" window of the "Create Instance" whizzard and select your snapshot from that list.

Delete your virtual machine

Make sure you delete your virtual machine after usage. Machines which are in shutdown state will still lock the required ressources. Other colleagues may want to use the ressources too.

Custom Startup Scripts

When launching an new instance, you can provide a script in order to customize your instance via cloud-init at startup.

Place your script in the "Configuration" tab in the "Launch Instance" whizzard.

Set a user password

You can set a password for the default ubuntu oder debian user at startup.

#cloud-config
chpasswd:
  list: |
    ubuntu:set_your_password_here
    root:set_your_root_password_here
  expire: False

Setting up an graphical environment

You can run ssh -X to your machine and execute any graphical binary, but in some cases this might not be sufficient enough.

We do not recommend the console in the openstack dashboard since it is not meant for productive usage.

Example: Setting up an VNC server

Log in to your virtual machine and install the required software. In this exmaple, we use Ubuntu 18.04 as operating system.

Choose your desktop environment

We do not provide an default desktop environment, so you can choose your own.

In this example we will use XFCE, since it's small in size and dependencies and sufficient enough for most use cases.

Let's install XFCE:

ubuntu@xserver-test:~$ sudo apt-get update
[...]
ubuntu@xserver-test:~$ sudo apt-get -y install xfce4 xfce4-goodies

Set up your VNC server

We prefer thightvncserver:

ubuntu@xserver-test:~$ sudo apt install tightvncserver

Run the vncserver for the first time.

ubuntu@xserver-test:~$ vncserver 
You will require a password to access your desktops.

Password: 
Verify:   
Would you like to enter a view-only password (y/n)? n

New 'X' desktop is xserver-test:1

Creating default startup script /home/ubuntu/.vnc/xstartup
Starting applications specified in /home/ubuntu/.vnc/xstartup
Log file is /home/ubuntu/.vnc/xserver-test:1.log

The password must be between six and eight characters long. Passwords more than 8 characters will be truncated automatically.

Once you verify the password, you'll have the option to create a a view-only password. Users who log in with the view-only password will not be able to control the VNC instance with their mouse or keyboard. This is a helpful option if you want to demonstrate something to other people using your VNC server, but this isn't required.

You can later change the password later with vncpasswd.

When VNC is first set up, it launches a default server instance on port 5901. This port is called a display port, and is referred to by VNC as :1. VNC can launch multiple instances on other display ports, like :2, :3, and so on.

You can determine the display port from the output of your vncserver at startup:

New 'X' desktop is xserver-test:1

In this case VNC is running on display port :1.

Stop the VNC server for now:

ubuntu@xserver-test:~$ vncserver -kill :1

Configure the VNC server

We want to start an XFCE environment when we launch the VNC server. Therefore we change the startup script for the VNC server. Edit your ~/.vnc/xstartup file and change it to:

#!/bin/bash
xrdb $HOME/.Xresources
startxfce4 &

Startup the VNC server again, but this time maybe with a higher screen resolution. In this case: 1400x900.

ubuntu@xserver-test:~$ vncserver -geometry 1400x900

Connecting to your VNC session

Since VNC connections are not encrypted we recommend to use a ssh session as transport layer and tunnel the VNC session.

From your local computer start a ssh tunnel:

ssh -L 5901:127.0.0.1:5901 -C -N ubuntu@10.106.241.XXX

In this case we're binding port 5901 of the remote connection to port 5901 on your local machine. The -C switch enables compression, while the -N switch tells ssh that we don't want to execute a remote command. Replace the XXX with your assigned floating IP-address.

Now you can run any VNC viewer on your local computer and point it to localhost:5901 or :1. We are using vinagre as VNC viewer.

$ vinagre :1 &