Users – Hostry Help Center

Create a Sudo User on Ubuntu

Alex — Mon, 07 Sep 2020 08:27:57 +0000

One of the best ways to ensure security while doing administrative work on your server is to run as a non-root user. After successfully purchasing a VPS from Hostry, the first task as root should be to set up a non-root user with a valid sudo.
This guide is applicable for Ubuntu distribution, for versions: 20.04 LTS, 18.04 LTS, 16.04 LTS.

Add a New User Account

To create a user account, you need to use the adduser command. We recommend using a strong password for the user! An example of a strong password is aoQ7w52!OKvA$Pfz. Next, you can enter values for user information, or press ENTER to leave these fields blank.

# adduser example_user
Adding user `example_user' ...
Adding new group `example_user' (1001) ...
Adding new user `example_user' (1001) with group `example_user' ...
Creating home directory `/home/example_user' ...
Copying files from `/etc/skel' ...
New password:
Retype new password:
passwd: password updated successfully
Changing the user information for example_user
Enter the new value, or press ENTER for the default
        Full Name []: Example User
        Room Number []:
        Work Phone []:
        Home Phone []:
        Other []:
Is the information correct? [Y/n] y

Add User to Sudo Group

You can add a new user to the sudo group using the usermod command

# usermod -aG sudo example_user

Test

Switch to a New user

# su - example_user

Make sure you are the new whoami user, then test sudo access with sudo whoami which should return root

$ whoami
example_user
$ sudo whoami
[sudo] password for example_user:
root

Done!

How to Set Unlimited Users and File descriptions on Linux server

Alex — Mon, 17 Aug 2020 09:21:22 +0000

Linux has a unique system for installing and changing the maximum number of user processes, uilimit. The default number of file descriptors that any process can open is 1024 per process.

Installing unlimited users and descriptions on the server

When you do this task, you get the error “too many files open limit”. This means that there is a limitation on opening Linux files according to the user’s session. To do this, add a line to /etc/sysctl.conf and run sysctl -p:

fs.file-max = 80000

Next, we check the default constraints. This can be done with the following command:

cat /proc/sys/fs/ file-max

file-max is the maximum file descriptor. This is a kernel setting applied at the system level. Also you can check the default values for the root user.

ulimit -a

It is also possible to set hard and soft limits by editing this vim file /etc/security/limits.conf

* hard nofile 600000
* soft nofile 600000

Set hard and soft limits for Linux user

linux hard nofile 600000
linux soft nofile 600000

Then run the following command to make the changes

sysctl -p

It is also possible to check how many files are open at the moment using following command

lsof | wc -l

You can check how many file descriptions are currently in use with the following command:

more /proc/sys/fs/file-nr

Check the file descriptor limit for the currently open file using the following commands

more /proc/sys/fs/file-max
sysctl -a | grep fs.file-max

After making the changes, you need to log out and log back in.