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Ventoy – open source tool to create bootable USB drives

Ventoy is an open source tool to create a bootable USB drive for ISO/WIM/IMG/VHD(x)/EFI files.

With ventoy, you don’t need to format the drive again and again, you just need to copy the ISO/WIM/IMG/VHD(x)/EFI files to a USB flash drive and load them directly.

You can copy many files at the same time, and ventoy will give you a boot menu to select them.

Official WebSite: https://www.ventoy.net/en/index.html

How to enable remote connections to MySQL server

Enabling remote connections to a MySQL server involves a few steps:

1. Configure MySQL Server

By default, MySQL server is configured to listen to the loopback IP address 127.0.0.1, which means it only accepts connections from the local machine. To allow remote connections, you need to modify the MySQL configuration file (my.cnf or my.ini or 50-server.cnf), typically located in /etc/mysql/ or /usr/local/mysql/etc/ or /etc/mysql/mariadb.conf.d.

Look for the following line in the configuration file:

bind-address = 127.0.0.1

And change it to:

bind-address = 0.0.0.0

This allows the MySQL server to listen on all available network interfaces.

2. Grant remote access to MySQL user

By default, MySQL server creates a user root with full administrative privileges, but it only allows access from the local machine. To enable remote access for this user, you need to grant it permission to connect from a remote IP address.

Log in to the MySQL server as root user and execute the following command:

GRANT ALL ON . TO 'root'@'%' IDENTIFIED BY 'yourpassword';

This grants the user root access to all databases and tables from any IP address (%). Replace ‘yourpassword‘ with a secure password of your choice.

3. Restart MySQL server

After modifying the configuration file and granting remote access to the user, you need to restart the MySQL server to apply the changes.

On Ubuntu or Debian, use the following command:

sudo service mysql restart

On CentOS or Fedora, use:

sudo systemctl restart mysqld

4. Open MySQL port on firewall

If you have a firewall running on the MySQL server, you need to open the port that MySQL server is listening on (usually port 3306) to allow incoming connections.

On Ubuntu or Debian, use the following command to open the port:

sudo ufw allow 3306/tcp

On CentOS or Fedora, use:

sudo firewall-cmd --add-port=3306/tcp --permanent
sudo firewall-cmd --reload

Once you have completed these steps, you should be able to connect to the MySQL server remotely using the root user and the password you set in step 2.

However, note that allowing remote access to the MySQL server can pose a security risk if not properly secured.

Therefore, it is recommended to only allow connections from trusted IP addresses and to use a secure password.

Disable exec, shell_exec, system, popen and Other PHP Functions To Improve Security

PHP has a lot of functions which can be used to crack your server if not used properly. You can set list of functions in php.ini using disable_functions directive. This directive allows you to disable certain functions for security reasons. It takes on a comma-delimited list of function names.

Open a terminal application or login to your server over the ssh session using ssh command. Open php.ini file using a text editor such as vim command or nano command:

sudo nano /etc/php/8.0/fpm/php.ini

Find disable_functions and set new list as follows:

disable_functions =exec,passthru,shell_exec,system,proc_open,popen,curl_exec,curl_multi_exec,parse_ini_file,show_source

We also recommend to disable allow_url_include and allow_url_fopen for security reasons:

allow_url_fopen=Off
allow_url_include=Off

Restart PHP with command:

systemctl restart php8.0-fpm

Install Wireguard on Debian 11

First update package list and upgrade your operating system:

sudo apt update && sudo apt upgrade

To install Wireguard use command:

sudo apt install wireguard

Now check if Wireguard installed correct:

sudo modprobe wireguard

If this command dose not show anything, Wireguard installed correct. If You get error like this: modprobe: FATAL: Module wireguard not found in directory /lib/modules/4.19.0-12-686, install this package:

sudo apt install linux-headers-$(uname --kernel-release)

How to check an hard drive health in Linux using smartctl

The smartmontools package is generally available in the default repositories of all the major Linux distributions. It contains two utilities useful to check the status of storage with S.M.A.R.T support (Self Monitoring Analysis and Reporting Technology): smartcl and smartd.

The former is the utility we use directly to check S.M.A.R.T attributes, run tests, or perform other actions; the latter is the daemon which can be used to schedule operations in the background.

Tu install smartmontools use command:

sudo apt install smartmontools

Checking if SMART is enabled

Let’s become familiar with the smartctl utility. The first thing we want to check is if S.M.A.R.T support is active on the device. To perform this operation we can run the smartctl utility with the -i option (short for –info):

sudo smartctl -i /dev/sda

If SMART support is disabled we need to enable it:

sudo smartctl -s on /dev/sda

Getting S.M.A.R.T information with smartctl

To get information about hard drive /dev/sda use command:

sudo smartctl -a /dev/sda

Very important parameters to check are, among the others, “Reallocated_Sector_Ct” and “Current_Pending_Sector”. In both cases if the RAW_VALUE is something other than 0, we should be very careful and start to backup data on the hard drive. The Reallocated_Sector_Ct is the count of sectors on the block device which cannot be used correctly.

When such a sector is found it is remapped to one of the available spare sectors of the storage device, and data contained in it is relocated. The Current_Pending_Sector attribute, instead, is the count of bad sectors that are still waiting to be remapped. If you want to know more about the S.M.A.R.T attributes and their meaning, you can begin to take a look at the Wikipedia S.M.A.R.T page.

Proxmox – cluster not ready – no quorum [SOLVED]

This error occurs when we remove a node from the cluster.

If the cluster has 2 nodes and the two nodes are mentioned to access the quorum.

After removing a node from the cluster only a single node is active. Thus the quorum permission becomes a read-only state.

To resolve the error we change the node from 2 to 1 in the default configuration.

The sample error looks like:

Cluster not ready – no quorum? (500)

First we login to the Proxmox server.

Then we check the state of the cluster using the command

pvecm status

From the result, we find that the Quorum activity is blocked.

Thus we execute the below command to change the votes from 2 to 1.

pvecm expected 1

After executing the command we will be able to delete the VM.

If the VM gets locked during the process, we unlock the VM using the command

qm unlock

Now if you want, you can delete cluster width this commands:

systemctl stop pve-cluster corosync
pmxcfs -l
rm /etc/corosync/*
rm /etc/pve/corosync.conf
killall pmxcfs
systemctl start pve-cluster

Or you can remove only one node from cluster with this documentation:

https://pve.proxmox.com/wiki/Cluster_Manager#_remove_a_cluster_node