Hello,
I didn't write a article long time. In fact, I don't need to explain anymore, but I have a busy. I have changed the company. Today, I come back. Roughly two days ago, I met the incident about high load. My colleagues did to it, bu he didn't find out anything. He told me: Tien, I didn't see anything related the high load. Because, as you see, the load of top process is okay. Tien: Okay, I will...
[HOW TO] install x11vnc on CentOS 6/ CentOS 7
Few weeks ago I received the requirement from developer when he need to remote control to server on company.
I talked him: please wait me a minutes
And then, I installed x11vnc on server. You was familiar with x11vnc, if you didn't also nothing. On this article I will show you how to install x11vnc? how to implement it?
Firstly you need to install x11vnc from repositories as below:
yum search...
[HOW TO] install erlang, elixir on CentOS 6
Roughly 30 minutes ago I installed Erlang & Elixir into our server. It doesn't matter for everyone but until when everyone need help lolz.
So I write down the shortly instruction below.
I. What is erlang & elixir?
Please google to know it.
II. How to install?
Please ensure wget already installed on your server. The next commands retrieve a package that adds a new repository...
[HOW TO] set umask for user has /sbin/nologin environment
Come back to the last week, I worked on case "change umask for SFTP/ SSH user"
At that time, I simply thought that it is umask. So I added umask to ~/.bashrc and ~/.bash_profile.
But nothing to change. It means that I need think logically.
User login -> ssh -> pam.d/ssh -> /etc/profile (~/.bash_profile)
Why?
A few second I see that user's ssh/ sftp has shell environment is /sbin/nologin....
[HOW TO] check slot RAM information on Linux Operating System
One day you need to increase memory for physical server at Data-center. But you can't shutdown it to check the available slot. What's up next?
Luckily if you are using Linux Operating System. Because Linux has dmidecode to check hardware information.
I will tell you about dmidecode. In general you need to deeply understand what are you doing. I learned this mythology by my close friend.
dmidecode...
[HOW TO] delete password Linux user
Sometimes you need to reset password Linux user, and the question appears: how to delete Linux user password?
The answer is simple.
Firstly all user encrypted passwords are stored in /etc/shadow file. You login as a root user. You type the following command to delete a user password:
passwd --delete user_name
or
passwd -d user_name
Above command will make password empty.
Tiến Phan...
[HOW TO] change font type and font size pantheon terminal elementary OS
I look in the terminal windows in Elementary OS. Font size looks like small, so it makes the eyelids feel less tired.
What is going on? I need to resize of the terminal font.
Finally I found the method to do it, I use below command:
gsettings set org.pantheon.terminal.settings font 'Roboto Mono 12'
And I look over the terminal, wow already changed the font size.
gsettings - GSettings configuration...
[HOW TO] fix HAPROXY Setting tune.ssl.default-dh-param to 1024 by default, if your workload permits it you should set it to at least 2048
Error:
Starting haproxy: [WARNING] 052/161359 (16821) : Setting tune.ssl.default-dh-param to 1024 by default, if your workload permits it you should set it to at least 2048. Please set a value >= 1024 to make this warning disappear.
...
[HOW TO] validate haproxy configuration
I just changed haproxy.cfg. I want to ensure haproxy.conf is valid before restarting haproxy service.
So I check haproxy manual
$man haproxy
I see paremetter -c -V and -f which validate the syntax.
Finally I use this to validate
haproxy -c -V -f /etc/haproxy/haproxy.cfg
I hope this helps anyone looking to check the synctax haproxy.cfg
Tiến Phan - R0039
Knowledge is Endless
Sharing for Su...
[HOW TO] determine the serial number of a computer linux
Q: Hello, Do you want help me get the Laptop's serial number?
A: Easy :D wait me
Q: Nice!
A: Ping ping!!! please open terminal and run below execute command
"sudo dmidecode -t system | grep Serial"
Q: Thank you so much guys
Tiến Phan - R0039
Knowledge is Endless
Sharing for Succes...
[HOW TO] fix Error: xz compression not available
The last week I installed epel7 on CentOS6, and I got this error
Error: xz compression not available
Holy shit, how to solve it?
Simplicity:
yum remove epel-release
yum clean all
yum install epel-release
yum clean all
Tiến Phan - R0039
Knowledge is Endless
Sharing for Success...
[HOW TO] get up time process linux?
Once day you want to get the up time of application/ process. But you cannot really tell how long the process has been alive. To get this you may use a couple of commands like the following:
cattek@cattek:~$ ps -ax | grep nylas
7290 ? Sl 0:22 /usr/share/nylas/nylas
7294 ? S 0:00 /usr/share/nylas/nylas...
[HOW TO] fix Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'
When I reset 'mysql' root password, I couldn't do it. MySQL shows the notification:
Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'
Firstly I kill all mysqld's process with
$sudo killall -9 mysql
But nothing to show.
Wait wait, I see /var/run/mysqld/mysqld.sock, but I couldn't found this.
Finally I found the solution:
$sudo /etc/init.d/mysql stop
$sudo...
[HOW TO] Please, commit your changes or stash them before you can switch branches.
In the morning, I pull git to deploy, and unlucky, this paragraph shows me:
Please, commit your changes or stash them before you can switch branches.
Ya I see, a long time ago, I changed one line on file. So it don't like the git repositories file. Next, I have to change/ recovery file on my local as git repositories file.
I see it commons sense. So somebody know the method to fix. Next, google.
In...
[HOW TO] script automatically call skype
In the morning my boss calls me: Tien, why do you don't write script automatically call skype? I see the admin girl don't exactly run on time for it. So please write windows script.
Tien: ya I understand. It is easy to write.
Drop call...
In the afternoon, I go to office, and start to write the script.
Most often, admin girl runs skype to call hanoi's office by hand. She has a lot of works, so...
[HOW TO] Validate haproxy.cfg
In the morning I change the haproxy.cfg, but I don't want to restart the haproxy. Because it can make incident for our infrastructure.
So I think I need to validate haproxy configuration file. Luckily haproxy always support that.
Way is
/usr/sbin/haproxy -c -V -f /etc/haproxy/haproxy.cfg
Configuration file is valid
Good to see. I hope this help you to check the syntax of haproxy.cfg...
Linux Users and Groups - Base knowledge
Sometimes you have confused about Linux user, in this article, I show you:
How to find out what groups?
/etc/group is a text file which defines the groups on the Linux system. You can use 'groups' command toe display group memberships using the following syntax:
groups user-name
How do I find out the primary group membership?
getent group user-name
Add a new group
groupadd group-name
Add...
Hướng dẫn sử dụng pin laptop hiệu quả
Chào mọi người,
Trong vô vàn thông tin về pin laptop mọi người đã biết như: dùng pin thế nào để tuổi thọ được lâu? thế nào để không bị chai pin? blah blah
Anh em giang hồ thì ẩn mình muôn phương, mỗi người mỗi kiểu nói. Hôm nay mình mang đến cho mọi người một cách thức sử dụng PIN. Vui lòng xem đây là tài liệu tham khảo, hãy đọc & suy nghĩ, đối chiếu với những cách thức khác bạn đã biết...
[HOW TO] Microsoft Edge can't be using the Built-in Administrator account. Sign in with a different account and try again
Microsoft Edge can't be using the Built-in Administrator account. Sign in with a different account and try again
How to fix?
Open Run box in Start Menu
Typing secpol.msc
Under Local Policies/Security Options navigate to "User Account Control Admin Approval Mode for the Built-in Administrator account"
Set the policy to Enabled
Open Run box or cmd, typing gpupdate to force restart Local Group Policy
Thank...
[HOW TO] sharing tab missing in Folder Properties
A few day ago, I had a issues with Windows 10. Sharing tab missing in Folder Properties and Context Menu.
Account Assistant told me she want to create a folder share. Finance's software partner need it to install finance software. Easy, I think so. But, unluckily when I team-viewer. I don't see Sharing tab in Folder Properties and Context Menu.
What's going on?
It looks like...
[HOW TO] Windows 10 Upgrade Assistant 99%
This morning Marketing's girl came back to me. She told me to help her upgrade Windows 7 to Windows 10. Unfortunately I had a lot of task today, so I told her that I had no free time to do. But she can put it on my work space. Because I will come back when I have free time socket.
Three hours later, I work on her computer. I re-open up memories, she don't like Windows 7. She like watching media,...
One of the the best definition that I like /'mou.ka/
One of the the best definition that I like:moca noun /'mou.ka/
The team who dare to turn their dreams into others' reality. LOL, Kidding. Just a bunch of handsome geeks.
One a shiny Sunday afternoon I clean my room, and I see the old t-shirt
(Kể từ sau năm 2016 tôi không còn tin đây là sự thật ... 0i0...
[HOW TO] fix Required CD/DVD drive device driver is missing on WIndows 7
Today I come back to Windows. A new Quality Control staff is going to join our company in the next week. And I have to prepare the laptop for her.
In front of me is two laptops. One is Lenovo Thinkpad X220, the best laptop in my experience. Another is Dell Latitude E5250.
With Thinkpad X220, I have to clean up, and upgrade to Windows 10 as is her want. (She works in Marketing department). Microsoft...