Add swap to CentOS without reboot

Add 4G swap


How to encrypt and decrypt .cpt file

What is .cpt extension?

.cpt is a encrypted file format, you can use ccrypt to create and decrypt .cpt file


How to encrypt and decrypt .cpt file

Encrypt a file

Decrypt a file.


How to install ccrypt

Install ccrypt on CentOS

Install ccrypt on Debian/Ubuntu


CentOS 7 unable to login, display login incorrect immediately after input login name


Unable to login linux console, always show login incorrect for any login name



Selected some security profile(e.g. PCI-DSS) during installation, but network connection is unavailable.

Installer unable to download some packages from the internet, and caused installation failure. You may feel the installation time longer than no security profile.


In my case is CentOS installer missing the web proxy settings 🙁


How to Fix

Select other security profile or setup correct network connection, and re-install the system.



CentOS-7 Installer Security Profiles

2.1. Requirements

These profiles require a connection to the internet to install. If you select a security profile that can not connect to the internet on port 80 (to, your install may fail spectacularly and not even allow access to the console locally. Please only try these profiles while connected to the internet.

Packages will be installed from the internet if you use security profiles, even if those packages also reside on the ISOs.


How to Install ffmpeg on RHEL/CentOS 7

Install ffmpeg via ATRPMS repo


Try convert WAV file to MP3 format



How to Install NGINX and PHP-FPM on RHEL/CentOS 7

Basic Server Setup







Update Configuration






Create Virtual Hosts





Setup Firewall (Optional)


SELinux Settings (Optional for SELinux enabled)


Reboot after Setup



Mounting a Cloud Storage Buckets as a File System on CentOS 7 Compute Engine Instances


I need to mount a Google Cloud Storage Buckets to file system, and grant access to the web server.



Use the Google Cloud Storage FUSE (gcsfuse) tool to mount a Cloud Storage bucket to your Compute Engine instance.




  • I have a bucket named yctin-bucket
  • I want to mount this bucket to /cloud/yctin-bucket/
  • I was generated the Google Service Key, and stored into /src/gcloud_service_account.json


Mounting a bucket


To unmount the bucket




Install & Setup Google Cloud SDK (gcloud command) on RHEL / CentOS 7


bash: gcloud: command not found



Install & Setup Google Cloud SDK



1. Installing SDK



2. Initializing Cloud SDK



3. Authorizing Cloud SDK Tools






How to Install MySQL 5.7 on RHEL/CentOS 7

Basic Server Setup




Setup MySQL 5.7



Setup Firewall (Optional)


Reboot after Setup


Optional Settings for MySQL 5.7

Disable MySQL Strict Mode



Fix MySQL Password Expired

To establish a global policy such that passwords never expire.

Update /etc/my.cnf