Cloud from A to Z: References

Key Points

Introduction	Cloud computing is very flexible and has many diverse uses. Setup of Alliance cloud environments is left to its users, enabling great flexibility but requiring more knowledge. In this course we will setup a cloud environment to run a Jekyll site.
Why static websites?	Easier to dive into the components making up a site. Static websites render faster as code doesn’t need to be run first, databases don’t need to be queered. Easier to backup as static websites are a set of static files that can just be copied. Popular static websites have far fewer or no security patches required as compared to dynamic sites.
First Jekyll site	Jekyll converts Markdown to HTML Site wide configuration in _config.yml YAML is used to express settings using key : value pairs Setting up a site in a new location often requires changing the sites baseurl The jekyll build command generates a site from Markdown and a theme
Page front matter
Site configuration
Pages and markdown I
Pages and markdown II
Pages and markdown III
Posts and assets
How the Internet works	Computers often have an IP on a LAN and connect to the Internet through a router. You can see what your computer’s IP address is by using either ipconfig on windows or ifconfig commands on linux or Mac. You can see your computer’s public IP using the site ipv4.icanhazip.com. Ports allow computers and routers to differentiate types network traffic.
Introduction to cloud computing	Elasticity refers to the ability to scale devices up or down to meet demand. A Virtual Machine or Virtual Device is simulated with software running on physical hardware. A cloud allows one to borrow or rent virtual devices on-demand. Infrastructure as a Service (IaaS): the service provider provides you with the ability to create and manage virtual devices. You have complete control over VM configuration. Platform as a Service (PaaS): the service provider provides you with an environment to build and setup your software. Software as a Service (SaaS): the service provider provides the software and all the infrastructure and operating system configuration and management required to run the software. (e.g. gmail). OpenStack is a cloud operating system which allows you to manage your virtual devices.
Creating a keypair	A shell is a text based method for interacting with a computer. SSH is a Secure SHell that allows remote interaction with a computer. An SSH key pair allows a user to be authenticated on a remote computer. The Linux filesystem is a tree with / at the root and directories creating branches. The cd command is used to change directories. The pwd command is used to display the current working directory. The ls command is used to list the directory structure. The ssh-keygen command is used to create key pairs. The cat command is used print the contents of a file to the terminal. The chmod command is used change the file mode or permissions. The private key, id_rsa, must only be readable and writable by the file’s owner.
Creating a persistent virtual machine	The flavor of a VM prescribes the hardware profile of the VM. A boot source specifies from what the VM should boot. A public key must be inject into the VM in order to connect to it. A floating IP must be added to a VM to connect to it from outside the local network in the cloud. Port 22 must be opened in the security rules to allow SSH to connect to the VM. A security group controls which ports to allow traffic in and out on.
Applying updates	Use the sudo command to run commands following it as an administrator. Use sudo apt update to update the package list. Use sudo apt upgrade to upgrade packages. Reboot after updates have been installed by running the reboot command. You may need to repeat the apt update, apt upgrade, reboot process a few times to ensure all updates have been applied.
Creating a web server	Use apt search to find a specific package name. Use apt install to install packages. Open port 80 in your security group for HTTP access to your site.
Installing Jekyll	Ruby is a programming language. A Gem is a Ruby package. Jekyll is a Ruby Gem. Installing Gems in your home directory is preferred to system wide installation.
Moving your jekyll site
Hosting a site on github
Remote desktop primer/outline	Remote desktop allows you to run a graphical user interface remotely on your VM VNC is a software that allows you to use a remote desktop VNC runs on ports 5901 and upward VNC traffic is not secure We can use VNC securely by running it through an SSH tunnel
Remote desktop foundation	There are a lot of choices for window manager to use There are a lot of choices for VNC server to use
VNC viewer	TigerVNC viewers are available for many popular platforms
VNC, the wrong way	We can score an easy win by doing VNC the wrong way (but we shouldn’t) We can expose our VM to unnecessary risk VNC traffic is not secure by default Reducing the holes in your firewall enhances security Binding a server to only accept connections from localhost enhances security
VNC through a tunnel	We can set up a secure VNC connection with an SSH tunnel All of our SSH traffic goes through port 22 Traffic to our VNC server is encrypted Our VNC server only accepts connections from localhost
Remote Desktop Applications	There are many programs we can run on our remote desktop

Glossary

apt

is a command which provides an interface to the Ubuntu package management system. Commonly used sub-commands are update for updating the package list and upgrade for upgrading already installed packages to the newest version. See Ubuntu manual page for apt for more details.

bash

is a replacement for the earlier Bourne shell and is the default shell for most Linux distributions. See also shell for a more description of shells in general.

boot

or startup of a compute involves loading files and starting programs running which are contained on a boot source.

boot source

what the virtual machine boots from. Examples of a boot sources are volumes and images

cat

a command to concatenate files and print on the standard output.

cd

a command to change directories.

chmod

a command to change file mode bits or permissions.

CIDR

stands for Classless Inter-Domain Routing which can be used for specifying ranges of IP addresses.

cloud computing

A computing paradigm that enables access to shared pools of configurable computing resources.

command

a series of characters entered in a shell indicating an action you would like the operating system to perform.

CPU

or central processing unit, is the electronic circuitry within a computer that carries out the instructions of a computer program.

CPU oversubscription

is when one physical CPU runs two or more VCPUs. In this case the one real physical CPU will switch back and forth between running tasks for the two or more VCPUs.

compute flavor

is a virtual machine flavor which is configured for short temporary usage. Because data safety is often less of a concern they are designed with a 20 GB root ephemeral disk and often have an extra ephemeral data disk attached. An example of a compute flavor name is c1-7.5gb-30 which has 1 VCPU, 7.5 GB of RAM, and a 30 GB extra ephemeral data disk in addition to the 20 GB ephemeral root disk.

computer network

is a digital telecommunications network which allows nodes in the network to share resources and exchange data.

decryption

the process of transforming an encrypted message into its original form before the encryption took place.

DNS

or domain name server is a computer which matches domain names to IP addresses.

domain name

is an identification string that defines a realm of administrative autonomy, authority or control. In general, a domain name represents an IP resource.

encryption

a process of transforming a message into one which is only readable by authorized parties.

elasticity

The ability to quickly change the amount of resources being used based on demand.

ephemeral disk

a virtual disk residing on the physical node or hypervisor which runs the virtual machine. Ephemeral disks, as the name might suggest do not outlive their virtual machine, meaning that when their virtual machine is terminated or deleted the drive is also deleted.

flavor

defines the virtual hardware specifications of a virtual machine

floating ip

is an IP address which is publicly addressable from the Internet and which can be moved between virtual machines. Also referred to as a public IP.

FQDN

is a domain name that is completely specified with all labels in the hierarchy of the domain name system.

git

git if a free open source, source code management tool. It keeps versioned snapshots of your code and easily displays the differences from one snapshot to the next.

github

github.com provides a web platform for hosting git version control repositories.

hardware virtualization

or sometimes referred to just as virtualization is the presentation of simulated hardware by software. For example this virtual hardware could be routers, computers, or disk drives.

hostname

is a label that is assigned to a device connected to a computer network

hypervisor

is computer software or hardware that creates and runs virtual machines

IaaS

Infrastructure as a Service is a service which provides computing infrastructure often through use of cloud computing

image

an image is a file which contains the contents of a virtual drive or volume. Images are however more portable than volumes as they can be downloaded and uploaded to various clouds and used with software such as VirtualBox

instance

see virtual machine

IP address

Internet Protocol address is a numerical label assigned to each device connected to a computer network.

key pair

a pair of cryptographic keys used in asymmetric encryption. Asymmetric encryption uses a different key to encrypt a message, in this case a public key, and another, in this case a private key, to decrypt the message.

LAN

local area network is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building.

Linux

is a family of free and open-source software operating systems.

ls

a command to list the file system structure in the bash shell and many other common shells.

node

often refers to a computer within a computer network.

OpenStack

is open source software for creating clouds. See cloud computing

operating system

software which runs on a computer to manage computer hardware, data and common services for computer programs.

PaaS

Platform as a Service

persistent flavor

is a virtual machine flavor which is configured for long running or persisting virtual machines. These machines are typically for webservers and may spend substantial portions of their time not doing anything. As such they may have the VCPUs oversubscribed by up to a factor of 8. They are also meant to boot form a volume for added robustness. An example of a persistent flavor name is p1-1.5gb indicating a virtual machine with 1 VCPU and 1.5 GB of RAM.

port

identifies a specific process or a type of network service.

port-forwarding

also referred to as port mapping redirects communication requests from one address and port number to another while the data is traversing a network gateway or router

private IP

an IP address assigned to devices on a LAN and is only accessible from within the LAN. Private IP address often have the form 192.168.XXX.YYY.

private key

is a key which is part of a key pair which is intended to be kept private and is used to decrypted messages encrypted by the public key.

prompt

a set of characters presented in a shell to indicate it is waiting for a command.

public key

is a key which is part of a key pair which is intended to be distributed publicly and is used to encrypt messages to be decrypted by the private key.

public IP

see floating IP

pwd

a command to print the current working directory in the bash shell and many other common shells.

RAM

or random-access memory is a form of computer data storage that stores data for quick access by the CPU.

reboot

is the act of shutting down and then booting an already running computer. It is also a Linux command which can be issued to cause a computer to reboot.

root

can refer to the root of a file system, the root drive (which contains the root of the file system), or a root or administrative user.

router

is a networking device that forwards data between computer networks for example a WAN and a LAN

SaaS

Software as a Service

scalability

The ability to increase resources as needed.

security group

is a set of rules indicating how traffic can flow into and out of the virtual machines which are members of a security group.

security rule

is a rule for a particular port or range of ports dictating what IP address, range of IP addresses, or which security group are allowed to send or receive data.

shell

or more specifically a command-line interface is a user interface for interacting with an operating system by typing commands. A common shell is the Bash shell. Some times the word terminal and shell are used interchangeably but the shell defines which commands are used while a terminal is a means of interfacing with a shell and different shells can be used within a single terminal.

SSH

is a cryptographic network protocol for operating network services securely over an unsecured network, commonly used for remote command execution in a shell. It uses key pairs for authentication.

ssh-keygen

a command for creating key pairs.

static website

a static website is a web page that is delivered to the user exactly as stored, in contrast to dynamic websites.

sudo

is a Linux command which runs the command following it, supplied as an argument, as the root user or administrative user. See Linux man page for sudo for more details.

terminal

is a program for entering and displaying text, see also shell.

Ubuntu

is an operating system in the Linux family. Ubuntu is one of the more popular Linux based operating systems and is widely used in cloud environments. See the official Ubuntu page for more details.

VCPU

is a virtual CPU.

virtual device

is an emulation of a real physical device usually through means of virtualization software.

virtual machine

is a virtual device emulating a computer system which provides the functionality of a physical computer. A virtual machine runs on a real underlying computer.

VirtualBox

a software tool for creating and running virtual machines. See VirtualBox website for more details.

virtualization

see hardware virtualization

volume

a volume is a virtual disk drive that can be attached to a virtual computer as you would a real drive to a real computer.

WAN

wide area network is a computer network that extends over a large geographical distance. The Internet may be considered a WAN.