PRELIM NET TECH - H2

Compute services

It provides the computing power required for running services such as websites, office software, and data analysis.

Network services

It provides resource connectivity and isolation, such as data center networks and campus networks.

Block storage

features high performance and low latency, meeting different high I/O service requirements.

File storage

allows file sharing among multiple servers or enterprise departments.

Object storage

features a flat, easy scale-out architecture, which is suitable for cloud storage. It is mainly used for massive data storage, cold data backup, and software repository.

Storage services

It includes block storage, file storage, and object storage.

Virtualization

• It refers to the process of creating multiple VMs that share the hardware resources of a physical server.

• It is the fundamental technology that powers cloud computing.

• It is a key technology of cloud computing.

VM

It consists of disk files and description files, which are encapsulated in the same folder.

Partitioning (Main Features of Virtualization)

Multiple VMs can run on one physical server, which means that the virtualization layer can allocate the resources of a physical server to multiple VMs.

Isolation (Main Features of Virtualization)

If one VM on a server is faulty or infected with viruses, the other VMs can still run properly.

Encapsulation (Main Features of Virtualization)

VMs exist in the virtualization system as files. You can migrate VMs by cutting/copying and pasting files.

Independence (Main Features of Virtualization)

After being migrated to another physical server, a VM can properly run without any modification on the server because VM OSs are decoupled from physical hardware.

Hypervisor

• It is also called virtualization software or VM monitor.

• It is used to create and run VMs on physical servers.

Central Processing Unit (CPU)

It is the computing and control core of a computer system, which processes information and executes programs.

Memory

It is an important component of a computer system. It is used to store CPU computing data and exchange data between memory and external storage (such as hard disks).

Graphics Processing Unit (GPU)

It is a microprocessor that performs image computation on PCs, workstations, game consoles, and mobile terminal devices such as tablets and smartphones.

Elastic Cloud Server (ECS)

It is a VM on the cloud consisting of vCPUs, memory, OS, and EVS disks. You can use it on the cloud just like you would use your local PC or physical server.

Auto Scaling (AS)

It automatically scales compute resources based on your demands.

Image Management Service (IMS)

It provides image lifecycle management. With the IMS, you can create a system or data disk image from a server or an external image file.

Container

It is a lightweight, portable technology for application packaging. It is a standard unit that packages an application's code and all its dependencies, enabling the application to run across different computing environments.

2016

Microsoft launched Hyper-V containers in Windows Server.

2014

CoreOS introduced the container engine rkt as an alternative to Docker to improve container security.

2013

Docker was launched. It was initially an internal project of dotCloud, a PaaS company.

2008

LXC (the first, most complete implementation of Linux container manager) was implemented using cgroups and Linux namespaces.

2006

Google launched Process Containers.

2005

SWsoft released OpenVZ, which was similar to Solaris Containers.

2000

BSD released FreeBSD Jails based on chroot.

1979

Container technology was born and introduced as the chroot operation in UNIX.

Chroot

It provided an isolated file system for each progress so their root directories can be easily changed. This is the origin of OS virtualization.

FreeBSD Jails

It isolate users, networks, and other resources. An IP address was assigned to each jail, which is an independent, smaller computer system, for independent software installation and configuration.

OpenVZ

It uses a modified Linux kernel to provide virtualization, isolation, resource management, and checkpoints.

Process Containers

renamed as control groups (cgroups) later, were designed for limiting, accounting, and isolating resource usage (CPU, memory, disk I/O, network) of a collection of processes.

Docker

It was initially an internal project of dotCloud, a PaaS company.

Hyper-V

These containers are similar to Linux containers and provide isolation for each container so processes in a container are isolated from the outside.

Container image

It is dedicated to running a specific service and usually contains only the resources required for running the service.

VM image

It offers the operating environment (including the OS kernel) required by common processes and provides a complete collection of functions.

Cloud Container Engine (CCE)

It is a high-performance, high-reliability service through which enterprises can manage containerized applications.

Cloud Container Instance (CCI)

It is a serverless container engine that allows users to run containers without creating or managing server clusters.

SoftWare Repository for Container (SWR)

It allows users to easily manage the full lifecycle of container images and facilitates secure deployment of images for your applications.

Networks

It bridge devices and VMs and allow them to communicate with each other. Therefore, networks are essential for ICT infrastructure.

Broadcast and unicast

The communication between two devices is like that between people.

Router

It is a hardware device that connects two or more networks. It works as a gateway to read the address of each data packet and decide how to forward it.

Default gateway

It is a device that connects a subnet to an external network. When a device sends information to a host, a subnet mask determines whether the destination host is on the local subnet according to the destination address.

Virtual Local Area Network (VLAN)

It is a group of logical devices and users, which are organized based on functions, departments, and applications, regardless of their physical locations.