How to implement free HTTPS on your website?

As you know lets-encrypt is free and open Certificate Authority, but how to implement to your website? Here is a very useful website: Certbot .   For example: certbot instruction for Nginx on CentOS 7 certbot instruction for Apache on CentOS 6 Access the webpage above, following the steps guide, you will implement your website for free HTTPS certificate.


How to update/install glibc-2.14 on centos 6.x

Update reason:

  check installed glibc version:

  I have tried update glibc like below:

but didn’t work, so tried the solution like below steps: download glibc-2.14.tar.gz extract the download files and build, install in /opt/glibc-2.14:

  update glibc symbolic links:

  If you want restore glibc symbolic links :



How to find files created on a specific date?

1.How to find files modified / created /  accessed  on a specific date Example 1: find files modified on the 10th of December

Example 2: find files created on the 10th of December

Example 3: find files accessed on the 10th of December

  2.Then how to use find to delete the files found above



How to install Node.js and NPM on Centos?

Before installation, please check your server operation system, this time we will install node.js on centos 6.7:

Then you can check which yum repository you should use, please read Node.js Binary Distributions to find the yum repository Step 1. Add node.js yum repository

In my case, I chosed NodeJS 8.x on CentOS 6 Step 2: Install node.js and NPM



How to check changes before pulling from remote git repository

Check changes before pulling from remote git repository steps below: fetch the changes from the remote

show commit logs of changes

show diffs of changes

apply the changes by merge..

  Difference between Git Pull vs Git Fetch: Git pull will download and merge latest changes from the remote repository automatically. You don’t have chance to […]


How to use iptables to defend against reflection DDOS attack on Centos

Usually use iptables to drop the UDP fragmented packets, below is the iptables config example: vi /etc/sysconfig/iptables

  Reference: 1 HOW TO DEFEND AGAINST AMPLIFIED REFLECTION DDOS ATTACKS 2 DDoS attacks – an explanation of amplified reflective UDP-based attacks


AWS reinvent 2018 Slides index

Let’s take a look at AWS reinvent 2018 from these slides Leadership Session: Machine Learning (AIM202-L) – AWS re:Invent 2018 Serverless:It All Started in Vegas (DVC306) – AWS re:Invent 2018 Best Practices for Securing an Amazon VPC (NET318) – AWS re:Invent 2018 How Amazon WorkSpaces Powers the Hands-On Labs (BAP317) – AWS re:Invent 2018 A […]


How to connect Amazon EC2 Linux Instance if you lose Private Key

From AWS EC2 Management Console, click Instances, select the original instance (that you lose the private key) Memo the detail information of the original instance: the instance ID (i-xxxxxxxx), AMI ID (ami-xxxxxxxx), and Availability Zone of the original instance from the details pane. volume ID in the EBS ID field (vol-xxxxxxxx) under Block devices  the details pane. [EC2-Classic] […]


How to fix: Mysql ERROR 1820 (HY000): You must SET PASSWORD before executing this statement

The error means the logined user’s password was expired, you excute the sql to confirm:

  To resolve the error , you can reset the password:

  If you got error,  you also can drop the user and create it again.