Section 4: Cloud Computing

- extends the management of applications and services
- deploys an infrastructure in minutes
- deploy in specific parts of the world
- cost is based on the amount of use

- private: your own virtualized local data center
- public: available to everyone over the internet
- hybrid: mix of public and private
- community: several organizations share the same resources

- IaaS, sometimes called HaaS(hardware as a service)
- hard drive space, network connection, memory
- you're still responsible for management and security
- your data is out there, but more within your control
- web server providers

- SaaS, on-demand software
- no local installation, no programming
- central management of data and applications
- a complete application offering
- ex: Google Mail, Microsoft 365

- PaaS, no servers, no software, no maintenance team, no HVAC
- someone else handles the platform, you handle the development
- you don't have direct control of the data, people, or infrastructure
- trained security professionals are watching your stuff
- develop your app from what's available on the platform
- good for using pre-built modules as a foundation
- ex: SalesForce.com

- on premises: all client managed
- SaaS: provider managed
- HaaS: app-data-runtime-middleware-OS client managed
- PaaS: app-data client managed

- internal cloud: no resources shared, build your own cloud, pay for everything up front, no ongoing costs
- external cloud: share resources with public cloud, infrastructure owned by 3rd party, cost may be metered or up-front

- metered cloud services: you pay for what you use, cost to upload/store/download
- nonmetered: fixed cost/flat fee, you pay for a block of storage, no cost to upload/download

- rapid elasticity, scale up and down as needed, seamless to everyone
- the cloud enables instant resource provisioning
- systems are always available, redundancy provides availability
- file synchronization, information can be duplicated across cloud locations

- Desktop as a Service, basic application usage
- applications run on a remote server, VDI(Virtual Desktop Infrastructure)
- local device is a keyboard, mouse, and screen
- minimal OS on the client, no huge memory or CPU needs
- network connectivity has a big network requirement, everything happens across the wire

- run multiple OS on single desktop at the same time
- ex: macOS, windows 11, linux Ubuntu
- separate OS, independent CPU, memory, network, etc on one computer
- host-based, your normal desktop plus others
- standalone server that hosts virtual machines, enterprise-level
- around since 1967, with IBM mainframe

- need to run different app versions on the same system, run each app instance in a seperate VM
- application only runs on a previous OS version, create a VM with the older OS

- windows/macOS/Linux has their own strengths and weaknesses
- run different OS at the same time, move between each OS seamlessly, no rebooting
- save time and resources as you're only using one physical computer

- virtual machine manager, manages the virtual platform and guest OS
- may require a CPU that supports virtualization, can improve performance
- manages CPU, networking, and security

- Intel: Virtualization Technology(VT)
- AMD: AMD-V
- excess memory/disk space beyond OS requirements
- each guest OS is configured with the proper network configuration(standalone, NAT, bridged)
- virtual switch

- isolated testing environment, no connection to real world or production system, technological safe space
- virtualize development process, try or break some code
- additional development features to roll back to a previous snapchat and/or run additional systems

- develop, a secure environment, writing code, developers test in their sandboxes
- test, a separate virtual environment for testing, still in development stage

- sweet spot for the bad guys, no significant vulnerabilities yet
- VM escaping, malware recognizes its on a virtual machine, compromises the hypervisor, and jumps from one OS to another
- many hosted services are virtual environments, malware on one customer's server can gather information from another

- concern if using hosted services for VM, where there are many different customers on the same physical platform where anyone could potentially gain access to data from many different customers
- running OS as VM doesn't make it more secure
- security controls such as host-based firewall, anti-virus, anti-spyware
- watch out for rogue VMs, bad guys try to instsall their own system
- self-contained VMs provided 3rd parties are dangerous

- most client-side VM managers have their own virtual(internal) networks
- shared network address: VM shares IP address as physical host, uses a private IP address internally, uses NAT to convert to the physical host IP
- bridged network address: VM is a device on the physical network
- private address: VM does not communicate outside of the virtual network