12. Glossary

Active Directory

A directory service that Microsoft developed for Windows domain networks and is included in most Windows Server operating systems as a set of processes and services.

Ansible

Ansible is a free-software platform for configuring and managing computers, combines multi-node software deployment, ad hoc task execution, and configuration management. It manages nodes (Linux nodes must have Python 2.4 or later installed on them, Windows nodes require PowerShell 3.0 or later) over SSH or over PowerShell.

arbiter

MongoDB instances that are part of a replica set but do not hold data. Arbiters participate in elections in order to break ties.

Chef

Chef is a configuration management tool written in Ruby and Erlang.

chef-client

A chef-client is an agent that runs locally on every node that is under management by Chef. When a chef-client is run, it will perform all of the steps that are required to bring the node into the expected state.

CMON
ClusterControl controller backend service.
DN

A Distinguished Name (DN) is used to uniquely name a directory object.

Docker

An open-source project that automates the deployment of applications inside software containers, by providing an additional layer of abstraction and automation of operating-system-level virtualization on Linux.

FQDN

A fully qualified domain name (FQDN), sometimes also referred to as an absolute domain name, is a domain name that specifies its exact location in the tree hierarchy of the Domain Name System (DNS).

FreeIPA

FreeIPA is a Red Hat sponsored open source project which aims to provide an easily managed Identity, Policy and Audit (IPA) suite primarily targeted towards networks of Linux and Unix computers. It is easy to install/configure, and is an integrated security information management solution combining Linux (Fedora), 389 Directory Server, MIT Kerberos, NTP, DNS, Dogtag (Certificate System).

garbd

Galera arbitrator daemon.

HAproxy

HAProxy is a free, very fast and reliable solution offering high availability, load balancing, and proxying for TCP and HTTP-based applications.

innobackupex

A Perl script that acts as a wrapper for the xtrabackup C program. It is a patched version of the innobackup Perl script that Oracle distributes with the InnoDB Hot Backup tool.

innodb_buffer_pool_size

The size in bytes of the memory buffer InnoDB uses to cache data and indexes of its tables. The default value is 8MB.

keepalived

A routing software written in C to provide simple and robust facilities for loadbalancing and high-availability to Linux system and Linux based infrastructures. Widely used for IP failover between two load balancer servers.

knife

Knife is a command-line tool that provides an interface between a local chef-repo and the Chef server.

LDAP

The Lightweight Directory Access Protocol (LDAP) is a directory service protocol that runs on a layer above the TCP/IP stack. It provides a mechanism used to connect to, search, and modify Internet directories. The LDAP directory service is based on a client-server model.

mongodb-consistent-backup

Tool for getting consistent backups from MongoDB Clusters and Replica Set.

mongodump

A utility for creating a binary export of the contents of a database. Consider using this utility as part an effective backup strategy.

mongostat

A utility to provide a quick overview of the status of a currently running mongod or mongos instance.

MyISAM
Previous default storage engine for MySQL for versions prior to 5.5. It doesn’t fully support transactions but in some scenarios may be faster than InnoDB. Each table is stored on disk in 3 files: .frm, .MYD, .MYI
MySQL Group Replication

MySQL Group Replication is a recent MySQL plugin that brings together group communication techniques and database replication, providing both a high availability and a multi-master update everywhere replication solution.

mysqldump

The mysqldump client is a utility that performs logical backups, producing a set of SQL statements that can be run to reproduce the original schema objects, table data, or both. It dumps one or more MySQL database for backup or transfer to another SQL server.

netcat

A computer networking service for reading from and writing to network connections using TCP or UDP.

pg_dumpall

A utility for writing out all PostgreSQL databases of a cluster into one script file. The script file contains SQL commands that can be used as input to psql to restore the databases. It does this by calling pg_dump for each database in a cluster

php.ini

PHP configuration file where you declare changes to your PHP settings.

Primary Component

In addition to single node failures, the cluster may be split into several components due to network failure. In such a situation, only one of the components can continue to modify the database state to avoid history divergence. This component is called the Primary Component (PC).

ProxySQL

ProxySQL is an open source high-performance MySQL proxy with a GPL license.

Puppet

Puppet is an open source configuration management utility.

s9s-admin tools

ClusterControl helper scripts provided by Severalnines. The source code can be accessible at Severalnines Github repository.

top
Displays processor activity of your Linux box and also displays tasks managed by kernel in real-time.
xtrabackup

Percona XtraBackup is an open-source hot backup utility for MySQL - based servers that doesn’t lock your database during the backup.

XtraDB

Percona XtraDB is an enhanced version of the InnoDB storage engine, designed to better scale on modern hardware, and including a variety of other features useful in high performance environments. It is fully backwards compatible, and so can be used as a drop-in replacement for standard InnoDB.