Useful terms¶

AMD64: platform, the 64-bit version of the x86 instruction set, x86 means 32-bit OS
Ansible: an easy to use configuration management and orchestration tool; it is platform that can combine multi-node software deployment and ad hoc task execution; it’s configuration, deployment, and orchestration language are playbooks expressed in YAML format; Ansible is an automation engine similar to Chef or Puppet, that can be used to ensure deployment and configuration consistency across many servers, and keep servers and applications up-to-date
Bridged networking: connects a virtual machine to a network by using the network adapter on the host system, the virtual machine is a full participant in the network

../_images/bridged_networking.png — Fig. 32 Bridged Networking Configuration [1]¶

Client machine: machine which runs GIS.lab client system launched from GIS.lab server
Client’s root: a directory on GIS.lab server in which GIS.lab client is installed with a special tool named debootstrap; it has almost the same filesystem hierarchy as a standard Ubuntu desktop installation with GIS.lab integration changes - and this is what one can see in running GIS.lab client; from this directory is then created GIS.lab client image which is mounted over network as a client’s root partition during boot process
Configuration: an arrangement of functional units, often pertains to the choice of hardware, software, firmware, and documentation; it affects system function and performance
Containers: can share a single Linux Kernel and optionally other binary and library recources, compared with virtual machines that require a full operating system image for each instance
Customization: means doing some modification over an existing applications according to requirements of the client
Dev: development tools, software developer or device in PC

DHCP server: Dynamic Host Configuration Protocol is way how to set host’s IP address to automatically assign an IP address to any host on the network upon the request (in order for two hosts communicate on the same network using TCP/IP model, both hosts need to have an unique IP address); GIS.lab can run its own DHCP server

../_images/dhcp.gif — Fig. 33 DHCP server [2]¶

Django: is a free and open-source web framework, written in Python, which follows the model–view–controller architectural pattern with primary goal to ease the creation of complex, database-driven websites, reuse various components emphasizing principle of don’t repeat yourself
DNS server: Domain Name System is a protocol within the set of standards for how computers exchange data on the internet and on many private networks, known as the TCP/IP protocol suite; its basic job is to turn a user-friendly domain name like qgis.org into an IP address like 91.142.249.5 that computers use to identify each other on the network; also it is used to don’t have to remember IP addresses, domain names are much easier to remember; user will need at least one DNS server address but can enter up to three addresses in case one server is unavailable; if user does not know it’s DNS server addresses, Google has DNS servers that anyone in the world can use for free, the addresses of these servers are Primary 8.8.8.8 and Secondary 8.8.4.4

../_images/dns.jpg — Fig. 34 Domain name system workflow [3]¶

Gateway: is an IP address of the device that machine looks to for access to the internet; usually, it is the router’s IP address
GIS.lab node: GIS.lab client environment which runs on client machine
GIS.lab master: GIS.lab server environment which runs on host machine; it acts as conventional server providing boot service, file, geo-database or chat server
Git: is a distributed version control system often used to work on some code together, it allows groups of people to work on the same files at the same time to develop various software; it runs command line on local machine and allows to keep track of files and modifications to those files in something called repository; every developer can work independently and then merge changes together while everything is recorded by Git
GitHub: is a web side that allows to upload Git repositories online; unlike Git, GitHub provides graphical interface for private repositories and free accounts usually used to host open-source projects
GDAL: Geospatial Data Abstraction Library provides access to geospatial data, it is a cross platform C++ translator used for reading, writing and transforming raster (GDAL) and vector (OGR) data to the calling application for all supported formats; a variety of useful command line utilities for data translation and processing are used
GUI: Graphical User Interface
Hardware virtualization: refers to the creation of a virtual machine that acts like a real computer with an operating system; softwares executed on these virtual machines are separated from the underlying hardware resources
Host machine: is main machine where required softwares and GIS.lab package are installed
Chroot: is a tool which enables installation in client environment; installation to client’s root is done within chroot operation
I386, x86: ordinary platform, 32-bit microprocessor
IA64: platform, 64-bit microprocessor

IP address: Internet Protocol address is unique numerical identifier assigned to each device participating in a computer network that uses the Internet Protocol for communication; it is 32-bit numeric address written as four numbers 0.0.0.0 separated by periods, each number can be zero to 255; it is assigned as part of connecting to a network; it is used for identifying computer on the network; when connecting using DHCP, this address will periodically change (hence, the name dynamic), in case of static IP address configuration, address will never change
ISO: an archive file of an optical disc; image file is a snapshot of the data and layout of a CD or DVD, saved in ISO-9660 format widely used for storing CD content; it contains raw dumps of a magnetic disk or of an optical disc
LAN: Local Area Network is a computer network interconnecting computers within a limited area, e.g. school or office building
LDAP: Lightweight Directory Access Protocol is an open protocol that email and other programs use to look up information from a server, allows to access information directories and obtain these information
LXC: Linux Container is a lightweight virtualization technology on operating system level for running multiple isolated Linux systems, i.e. containers on a control host using a single Linux kernel
MAC address: Media Access Control address is kind of serial number assigned to every network adapter; no two anywhere should have the same MAC address; it is assigned at the time hardware is manufactured, the computer needs to have its MAC address registered in the DNS/DHCP so that it’ll be recognized and get the right IP address, six groups of two hexadecimal digits separated by colons 0:0:0:0:0:0 or by hyphens 0-0-0-0-0-0 or three groups of four hexadecimal digits separated by dots 0.0.0
Network mask: tells computer the size of the network to which it is being connected, it is formatted the same way as the IP address, but usually looks something like 255.255.255.0
NIC: Network Interface Card is a computer hardware component that enable connecting computer to a computer network physically. It is a circuit board or card that is installed in a computer
PXE booting: Preboot Execution Environment booting, is a method of having an end computer (client) boot using only its network card, it is industry standard client/server interface that allows networked computers that are not yet loaded with an operating system to be configured and booted remotely by an administrator, PXE provides e.g. DHCP, application program interfaces that are used by the client’s Basic Input/Output Operating System (BIOS), etc.

../_images/pxe.png — Fig. 35 PXE overview [4]¶

Serf: Service orchestration and management tool is a decentralized solution for service discovery and orchestration; it uses an efficient and lightweight gossip protocol to communicate with other nodes, it can detect node failures and notify the rest of the cluster

../_images/serf.png — Fig. 36 Serf as a decentralized solution for service discovery and orchestration.¶

Software framework: is an abstraction in which software providing generic functionality can be selectively changed by additional user-written code, thus providing application-specific software
Tmux: Terminal multiplexer is a software application usually used to multiplex several virtual consoles, enabling a number of terminals to be created, accessed, and controlled from a single screen; it may be detached from a screen and continue running in the background, then later reattached
Travis CI: a FOSS, hosted, distributed continuous integration service used to build and test software projects hosted at GitHub, it is configured by adding a YAML format text file to the root directory of the repository
Vagrant: a cross-platform tool for working with Virtual Machines, it does networking out-of-the-box and solves problems in a modular way, it represents the command line utility for managing the lifecycle of virtual machines, to describe the type of machine required for a project, and how to configure and provision these machines Vagrantfile with Ruby syntax is used, process means set up - downloading and installing Vagrant, configure - creating a single file with description and work - running
Vagrant box: the package format for Vagrant environment, it is used to bring up an identical working environment,
Vendor: supplier, a part of the supply chain