Uploading iso to Proxmox

To upload iso to proxmox, so that the iso can be used to create VM, please follow below steps

1. Login to proxmox

2. On the left hand side, expand Datacenter, until you see node/s

3. Expand the node until you see local. Click on "local"

4. On the right hand side, click "Content"

5. Click "Upload"

6. Select the iso file that you want to upload, and click "Upload"

7. Once uploaded, you will see the iso listed on the right hand side. Please refer below picture for clearer view

Install and Use Vagrant on Linux Mint 19 with Virtualbox

Vagrant is a tool for building and managing virtual machine environments in a single workflow. With an easy-to-use workflow and focus on automation, Vagrant lowers development environment setup time, increases production parity, and makes the "works on my machine" excuse a relic of the past.

We can always install vagrant from the repository, but the one in the repository is quite an old version, which is 2.0.2. So we will download the latest version from https://www.vagrantup.com/downloads.html. Since they do not provide a package for ubuntu/mint, we will use debian package.

To download the installer

$ wget -c https://releases.hashicorp.com/vagrant/2.2.7/vagrant_2.2.7_x86_64.deb 

To install vagrant

$ sudo apt install ./vagrant_2.2.7_x86_64.deb -y

Download virtualbox, if you still have not install it

$ wget -c https://download.virtualbox.org/virtualbox/6.1.4/virtualbox-6.1_6.1.4-136177~Ubuntu~bionic_amd64.deb

Install  virtualbox

$ sudo apt install ./virtualbox-6.1_6.1.4-136177~Ubuntu~bionic_amd64.deb -y

Let's say we want to create an ubuntu bionic virtual machine (VM) using vagrant. First we have to run init

$ mkdir -p  vagrant/ubuntu-bionic

$ cd vagrant/ubuntu-bionic

$ vagrant init hashicorp/bionic64

$ vagrant up

The init command will create a standard Vagrantfile, which can be used to define the specs of virtual machine we want to make.

The up command will use the Vagrantfile, and create a VM out of it.

Once all the downloading is done, the VM will be created, and you can login into the box using ssh command

$ vagrant ssh

And within just a few commands, you already have a working virtual machine without having to do the standard operating system installation just like when you create a virtual machine using the traditional way.

Installing Wordpress on Ubuntu 18.04 Using LEMP Stack

Installing wordpress on LEMP stack is not much different from installing in LAMP stack. For those who do not know, LEMP stands for Linux + Nginx + Mariadb + PHP stack, and LAMP stands for Linux + Apache + Mariadb/mysql + PHP stack. Check out my other post on how to install wordpress on LAMP stack on ubuntu.

As per the stack definition, there are 3 main components to be installed: nginx, mariadb and php.

Install nginx:
$ sudo apt install nginx -y

Install mariadb:
$ sudo apt install mariadb-server -y

Install php, php-mysql and php-fpm
$ sudo apt install php php-mysql php-fpm -y

Download wordpress code
$ wget https://wordpress.org/latest.tar.gz

Start mariadb
$ sudo systemctl start mariadb

Secure mariadb installation
$ sudo mysql_secure_installation

Create a database for wordpress
$ sudo mariadb -u root
MariaDB [none]> create database wpdb;
MariaDB [none]> grant all on wpdb.* to wpuser@localhost identified by 'wppassword';
MariaDB [none]> flush privileges;
MariaDB [none]> exit

Test the newly created user and db
$ mariadb -u wpuser -p wpdb
MariaDB [wpdb]> exit

Download wordpress
$ wget https://wordpress.org/latest.tar.gz

Extract wordpress
$ tar -xvf latest.tar.gz

Move wordpress directory to /var/www/html
$ sudo mv wordpress /var/www/html

Change ownership of the wordpress directory
$ sudo chown -R www-data /var/www/html/wordpress

Create nginx virtualhost configuration for wordpress
$ sudo nano /etc/nginx/conf.d/wordpress.conf

Add in below code (change the server name to refer to your ip address, since we do not have any domain at the moment)
server {
        listen   80;

        root /var/www/html/wordpress;
        index index.php index.html;
        server_name wordpress.10.0.0.5.nip.io;

        location / {
                try_files $uri $uri/ /index.php?q=$request_uri;
        }

        error_page 404 /404.html;
        error_page 500 502 503 504 /50x.html;
        location = /50x.html {
              root /usr/share/nginx/www;
        }

        location ~ .php$ {
                try_files $uri =404;
                fastcgi_pass unix:/run/php/php7.2-fpm.sock;
                fastcgi_index index.php;
                fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
                include fastcgi_params;
        }
}

Save the file and exit

Test nginx config for any syntax error

$ sudo nginx -t

Start nginx

$ sudo systemctl start nginx

Start php-fpm

$ sudo systemctl start php7.2-fpm

Open a web browser and put in you server_name address in the address bar, and you should be able to get the wordpress installation wizard. Press "Continue"

Press "Let's go!"

Fill up database details and press "Submit"

If everything is correct, you will get to "Run the installation" page. Click on "Run the installation" button. 

Fill up the necessary information for your wordpress blog, and click "Install wordpress" to finish wordpress installation

Expediting Files Copy to USB

Copying to usb is quite troublesome in linux, whereby the "cp" command or file manager reports that the file has been copied successfully, but if your usb drive has LED, you can see that the LED is flashing frantically as if it is doing some hard work in the background. 

This is due to the default ubuntu linux setting for kernel parameter called vm.dirty_bytes is being set 0 (unlimited), which means that after copying process has been started, the file will be copied to buffer as a whole, the process that started the copying (file manager or "cp" command) will be notified that copy has completed, but in the background, the file is actually sitting in the buffer, waiting to be written to the usb driver.

This will results in the file manager showing 100% copied, but the file is not actually being written to the usb.

One of the way to expedite the copy process is, by limiting the size of the buffer, so the file will get written to the usb faster. 

You can check what is the current buffer (vm.dirty_bytes) value by running:

$ sudo sysctl vm.dirty_bytes

vm_dirty_bytes = 0

Change the current value to something small (like 15MB)

$ sudo sysctl vm.dirty_bytes=15000000

Start the copying process

$ cp some-big-file /mnt

The copy process will complete faster.

To make the change permanent:

$ echo "vm.dirty_bytes=15000000" | sudo tee -a /etc/sysctl.conf 

Reboot your machine

$ sudo reboot

Once rebooted, check whether the value stays

$ sudo sysctl vm.dirty_bytes

vm_dirty_bytes = 15000000

Done.

Credit to:

- https://askubuntu.com/questions/1117832/copying-files-from-pc-to-pendrive-gets-stuck-at-the-end-on-ubuntu-16-04

- https://unix.stackexchange.com/questions/180818/gnome-nautilus-copy-files-to-usb-stops-at-100-or-near

Replacing Single Line Spacing with Double Line Spacing in VIM

Thanks to this post, I learned on how to replace blank lines in my text document into 2 blank lines, to make it neat and clear.

The original document, with single line spacing

My objective is to replace all single blank lines representing new lines, into 2 new lines instead. To do that in vim, I just need to press "escape" to enter command mode and type the command below, which is ":%s/^$/\r/g", where
%s is to replace all occurrence of the selection in a line
^$ for single blank lines
\r carriage return, which will print double blank lines

The result should be like below 

Save and quit as usual, and you get yourself a neater document with double line spacing. Enjoy :)