Year: 2019

systemd

Jovan Stosic March 30, 2019

The systemd software suite provides fundamental building blocks for a Linux operating system. It includes the systemd “System and Service Manager”, an init system used to bootstrap user space and manage user processes.

systemd aims to unify service configuration and behavior across Linux distributions.[8] It replaces the UNIX System V and BSD init systems. Since 2015, the majority of Linux distributions have adopted systemd, and it is considered a de facto standard.[1]

The name systemd adheres to the Unix convention of naming daemons by appending the letter d. It also plays on the term “System D“, which refers to a person’s ability to adapt quickly and improvise to solve problems.

SysV->upstart->systemd

Source: systemd – Wikipedia

systemd was last modified: March 30th, 2019 by Jovan Stosic

UNIX System V

Jovan Stosic March 30, 2019

UNIX System V (pronounced: “System Five”) is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, and 4. System V Release 4, or SVR4, was commercially the most successful version, being the result of an effort, marketed as “Unix System Unification”, which solicited the collaboration of the major Unix vendors. It was the source of several common commercial Unix features. System V is sometimes abbreviated to SysV.

As of 2012, the Unix market is divided between five System V variants: IBM‘s AIX, Hewlett-Packard‘s HP-UX, Oracle‘s Solaris,[1] Xinuos‘s UnixWare and illumos distributions being the open-source OpenSolaris continuation.[2]

Source: UNIX System V – Wikipedia

UNIX System V was last modified: March 30th, 2019 by Jovan Stosic

Quinn Kelsey

Jovan Stosic March 29, 2019

American baritone Quinn Kelsey made his Royal Opera debut in 2016 as Giorgio Germont (La traviata) and has since returned to sing Count di Luna (Il trovatore).

Kelsey was born in Honolulu. He represented the USA in the 2005 BBC Cardiff Singer of the World Competition. In 2008 he made his debut with the Metropolitan Opera, New York, as Schaunard (La bohème). He has since sung for many major international opera companies, including Lyric Opera of Chicago, San Francisco Opera, Santa Fe Opera, Canadian Opera Company, Zürich Opera, Hawaii Opera Theater, Norwegian National Opera, Paris Opéra, Semperoper Dresden, Rome Opera, Deutsche Oper Berlin, Frankfurt Opera and for the Bregenz and Edinburgh festivals. He has sung Germont for the Metropolitan Opera, Lyric Opera of Chicago, San Francisco Opera, Canadian Opera Company, Zürich Opera and in Seoul. Other Verdi roles include Rigoletto, Ezio (Attila), Count di Luna (Il trovatore), Montfort (Les Vêpres siciliennes), Paolo Albiani (Simon Boccanegra), Amonasro (Aida) and Falstaff.

Kelsey’s other repertory includes Enrico Ashton (Lucia di Lammermoor), Zurga (Les Pêcheurs de perles), Marcello (La bohème), Forester (The Cunning Little Vixen), Athanaël (Thaïs) and Sancho Panza (Don Quichotte). He has performed in concert and recital in the USA, the UK, Germany and Norway, in such repertory as Beethoven’s Symphony no.9, Mahler’s Symphony no.8, Orff’s Carmina Burana and Szymanowski’s Stabat mater.

http://www.roh.org.uk/people/quinn-kelsey

Quinn Kelsey was last modified: March 29th, 2019 by Jovan Stosic

Create and upload an Ubuntu Linux VHD in Azure

Jovan Stosic March 28, 2019

This article assumes that you have already installed an Ubuntu Linux operating system to a virtual hard disk. Multiple tools exist to create .vhd files, for example a virtualization solution such as Hyper-V. For instructions, see Install the Hyper-V Role and Configure a Virtual Machine.

Ubuntu installation notes

  • Please see also General Linux Installation Notes for more tips on preparing Linux for Azure.
  • The VHDX format is not supported in Azure, only fixed VHD. You can convert the disk to VHD format using Hyper-V Manager or the convert-vhd cmdlet.
  • When installing the Linux system it is recommended that you use standard partitions rather than LVM (often the default for many installations). This will avoid LVM name conflicts with cloned VMs, particularly if an OS disk ever needs to be attached to another VM for troubleshooting. LVM or RAID may be used on data disks if preferred.
  • Do not configure a swap partition on the OS disk. The Linux agent can be configured to create a swap file on the temporary resource disk. More information about this can be found in the steps below.
  • All VHDs on Azure must have a virtual size aligned to 1MB. When converting from a raw disk to VHD you must ensure that the raw disk size is a multiple of 1MB before conversion. See Linux Installation Notes for more information.

Source: Create and upload an Ubuntu Linux VHD in Azure | Microsoft Docs

Create and upload an Ubuntu Linux VHD in Azure was last modified: March 28th, 2019 by Jovan Stosic

Moodle – Reverse proxy frontend

Jovan Stosic March 25, 2019

A reverse proxy or surrogate is a proxy server that is installed in a server network. Typically, reverse proxies are used in front of Web servers. All connections coming from the Internet addressed to one of the Web servers are routed through the proxy server, which may either deal with the request itself or pass the request wholly or partially to the main web servers.

Contents

Requirements

  • You need ssl for authentication.
  • You run Apache 2.2 both in the backend and the frontend.
  • You run RHEL 5.2 Application stack 2 in the backend (php 5.2.6 + mysql 5 + apache 2.2.10).
  • You run Apache 2.2 as the frontend in any modern OS using trainer.moodle.org as url (My frontend apache runs on Windows 2003).
  • You installed moodle 1.9 to run from “/” the internal http server with SSL support on 10.1.1.24.
  • You have an external facing apache using SSL.

Configuration for the external server

http.conf

(snip)
ProxyPass / http://10.1.1.24/
ProxyPassReverse / http://10.1.1.24/
ProxyPreserveHost On
(snip)
Include conf/http-ssl.conf

http-ssl.conf

(snip)
ProxyPass / http://10.1.1.24/
ProxyPassReverse / http://10.1.1.24/
(snip)

config.php

<?php  /// Moodle Configuration File 

unset($CFG);

$CFG->dbtype    = 'mysql';
$CFG->dbhost    = 'localhost';
$CFG->dbname    = 'moodle';
$CFG->dbuser    = 'moodleuser';
$CFG->dbpass    = 'XXXXXXXX';
$CFG->dbpersist =  false;
$CFG->prefix    = 'mdl_';

$CFG->wwwroot   = 'http://trainer.moodle.org';
$CFG->dirroot   = '/var/www/moodle';
$CFG->dataroot  = '/opt/moodle_data';
$CFG->admin     = 'admin';

$CFG->directorypermissions = 00777;  // try 02777 on a server in Safe Mode

require_once("$CFG->dirroot/lib/setup.php");
// MAKE SURE WHEN YOU EDIT THIS FILE THAT THERE ARE NO SPACES, BLANK LINES,
// RETURNS, OR ANYTHING ELSE AFTER THE TWO CHARACTERS ON THE NEXT LINE.
?>

The tricky part

  • Go to Administration ► Security ► HTTP security and set Use HTTPS for loginsloginhttps to true.
  • You need to have the previous setup ready or you may lock yourself out of the server.

 

Source: Reverse proxy frontend – MoodleDocs

Moodle – Reverse proxy frontend was last modified: March 25th, 2019 by Jovan Stosic