Remove Node from Proxmox Cluster

Step 1 : Migrate all VMs to another active node

Migrate all VMs to another active node. You can use the live migration feature if you have a shared storage or offline migration if you only have local storage.

Step 2 : Display all active nodes

Display all active nodes in order identify the name of the node you want to remove Continue reading “Remove Node from Proxmox Cluster” »

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Add Geolocation to Graylog 2

The Graylog Map Widget is the plugin providing geolocation capabilities to Graylog. The plugin is compatible with Graylog 2.0.0 and higher, and it is installed by default, although some configuration is still required on your side. This section explains how to configure the plugin in detail.

In case you need to reinstall the plugin for some reason, you can find it inside the Graylog tarball in our downloads page. Follow the instructions in Installing and loading plugins to install it.

Configure the database

In first place, you need to download a geolocation database. We currently support MaxMind City databases in the MaxMind DB format, as the GeoIP2 City Database or GeoLite2 City Database that MaxMind provides.

The next step is to store the geolocation database in all servers running Graylog. As an example, if you were using the Graylog OVA, you could save the database in the /var/opt/graylog/data folder, along with other data used by Graylog. Make sure you grant the right permissions so the user running Graylog can read the file. Continue reading “Add Geolocation to Graylog 2” »

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Reclaim disk space from a sparse image file qcow2/ vmdk

Sparse disk image formats such as qcow2 only consume the physical disk space which they need. For example, if a guest is given a qcow2 image with a size of 100GB but has only written to 10GB then only 10GB of physical disk space will be used. There is some slight overhead associated, so the above example may not be strictly true, but you get the idea.

Sparse disk image files allow you to over allocate virtual disk space – this means that you could allocate 5 virtual machines 100GB of disk space, even if you only have 300GB of physical disk space. If all the guests need 100% of their 100GB disk space then you will have a problem. If you use over allocation of disk space you will need to monitor the physical disk usage very carefully.

There is another problem with sparse disk formats, they don’t automatically shrink. Let’s say you fill 100GB of a sparse disk (we know this will roughly consume 100GB of physical disk space) and then delete some files so that you are only using 50GB. The physical disk space used should be 50GB, right? Wrong. Because the disk image doesn’t shrink, it will always be 100GB on the file system even if the guest is now using less. The below steps will detail how to get round this issue. Continue reading “Reclaim disk space from a sparse image file qcow2/ vmdk” »

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Install Jitsi Meet and configure load balancing

Jitsi Meet is an open-source (Apache) WebRTC JavaScript application that uses Jitsi Videobridge to provide high quality, secure and scalable video conferences. It can be used as a replacement for proprietary services like Zoom, Whereby, Teams, Skype and many others.

Requirements

  • At least two Linux systems with Debian 10
  • DNS Record for your domain (in our case meet.example.com)

Prepare your system
First of all we prepare our system by updating all package lists and packages. To do so run the following commands.

apt update && apt upgrade -y

Basic Jitsi Meet installation
Next, please be sure that your FQDN is configured correct. Continue reading “Install Jitsi Meet and configure load balancing” »

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Enable authentication of Jitsi Meet

A basic installation of Jitsi Meet gets you up and running within shortest time, probably in less than 15 minutes. There are hardly any configuration changes necessary. Most important information is a fully qualified domain name (FQDN), and that’s it.

However such a default installation of Jitsi Meet is open. Meaning, that anyone knowing the URL of your server can create a new meeting room and start to have video conferences using your instance and probably causing additional cost. Continue reading “Enable authentication of Jitsi Meet” »

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Proxmox Cloud-Init OS template creation

Introduction

In this guide we will go over creating a Proxmox KVM Template from a Cloud Image. This same process will work for any Cloud-Init Openstack based image type you can find online.

Having done a number of these for our Proxmox based VPS service I wanted to post up a guide to help anyone else looking to do the same thing.

My workflow for customizing one of those for use with Proxmox with cloud-init deployment from WHMCS and root login is below. Once you setup one template you can rapidly reinstall new containers and test stuff.

Setup Environment

If not installed already installed you will need libguestfs-tools :

apt-get install libguestfs-tools

To edit the image before importing. We will use virt-edit which is a part of libguestfs-tools. Continue reading “Proxmox Cloud-Init OS template creation” »

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Install Discourse Forum with Nginx on Ubuntu 16.04

Step 1 – Install Docker on Ubuntu 16.04

The Discourse software is written in Ruby and Javascript, using PostgreSQL as the main database, and Redis as a cache and for transient data. We will install Discourse under the Docker container.
 
The installation process will be carried out on Ubuntu 16.04. So to begin with, install Docker using the command below.

wget -qO- https://get.docker.com/ | sh

 

After the installation is complete, check the docker service and make sure it’s already running on the system. Continue reading “Install Discourse Forum with Nginx on Ubuntu 16.04” »

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Install PHP 7 on CentOS 7

Enabling Remi repository

PHP 7.x packages are available in several different repositories. We’ll use the Remi repository which provides newer versions of various software packages including PHP.

The Remi repository depends on the EPEL repository. Run the following commands to enable both EPEL and Remi repositories:

sudo yum install epel-release yum-utils
sudo yum install http://rpms.remirepo.net/enterprise/remi-release-7.rpm

Yum may prompt you to import the repository GPG key. Type y and hit Enter.

In the following sections, we will be covering how to install PHP 7.x by enabling the appropriate Remi repository. If you already have PHP 5.4 installed on your system yum will update the PHP packages.

Installing PHP 7.3 on CentOS 7

PHP 7.3 is the latest stable release of PHP. Most modern PHP frameworks and applications including WordPress, Drupal, Joomla, and Laravel are fully supporting PHP 7.3.

Perform the steps below to install PHP 7.3 on CentOS 7.

Start by enabling the PHP 7.3 Remi repository:

sudo yum-config-manager --enable remi-php73

Install PHP 7.3 and some of the most common PHP modules:

sudo yum install php php-common php-opcache php-mcrypt php-cli php-gd php-curl php-mysqlnd

Verify the PHP installation, by typing the following command which will print the PHP version: Continue reading “Install PHP 7 on CentOS 7” »

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Ubuntu Firewall – UFW useful commands

Prerequisites

To follow this tutorial, you will need one Debian 10 server with a sudo non-root user, which you can set up by following Steps 1-3 in the Initial Server Setup with Debian 10 tutorial.

Step 1 – Installing UFW

Debian does not install UFW by default. If you followed the entire Initial Server Setup tutorial, you will have installed and enabled UFW. If not, install it now using apt:

sudo apt install ufw

We will set up UFW and enable it in the following steps.

Step 2 — Using IPv6 with UFW (Optional)

This tutorial is written with IPv4 in mind, but will work for IPv6 as long as you enable it. If your Debian server has IPv6 enabled, you will want to ensure that UFW is configured to support IPv6; this will ensure that UFW will manage firewall rules for IPv6 in addition to IPv4. To configure this, open the UFW configuration file /etc/default/ufw with nano or your favorite editor:

sudo nano /etc/default/ufw

Then make sure the value of IPV6 is yes. It should look like this:

/etc/default/ufw excerpt
IPV6=yes

Continue reading “Ubuntu Firewall – UFW useful commands” »

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Java plug-in does not work in Firefox after installing Java

Tested on Firefox 42 (old release) and Sea-Monkey 2.46/2.49.

There are several workaround options. The simplest method is noted first and is recommended. The remaining available options are not recommended for non-technical users.

Option 1: Add property name dom.ipc.plugins.java.enabled in Firefox preferences

1. Launch Firefox
2. Type about:config in the address bar
3. You will be presented with a Firefox warning about the configuration settings. After acknowledging the Firefox alert, you should see a listing of the configuration preferences.
4. Right-click anywhere inside the displayed list of preferences. Select New then select Boolean.
5. Add property name as dom.ipc.plugins.java.enabled
6. Add Preference name as dom.ipc.plugins.java.enabled.
7. A window will be displayed, select false. Then select OK.  Continue reading “Java plug-in does not work in Firefox after installing Java” »

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