Initialize A New Server Instance
Upon creating a new server on a remote machine by a VPS provider such as Linode or Digital Ocean, perform the following steps to initialize the server environment properly with the right admin access.
Set up SSH
Using Linode as an example, during the initialization of a new instance (say, 12.34.56.78), Linode would require creating a root password. On local machine, login with user root for the first time.
ssh root@12.34.56.78
Answer Yes when prompted for continuing connecting to this new host from the local machine. After 12.34.56.78 is permanently added to the list of known hosts, the connection will be closed. Login again with root's password.
ssh root@12.34.56.78
Upon successful login, Ubuntu's welcome message will be displayed.
Add new sudo user
On server, login as root user.
adduser userjoe
Provide answers to complete creating userjoe:
- Password (required)
- Full Name (optional)
- Room Number (optional)
- Work Phone (optional)
- Home Phone (optional)
- Other (optional)
Grant this new user sudo privilege.
usermod -aG sudo userjoe
Check all the current users that have sudo privileges.
getent group sudo
Test the login for the new userjoe. Log out from user root, then login as userjoe with the password.
ssh userjoe@12.34.56.78
It's better to use userjoe than root.
Login with root should be limited to the minimum
Logged in as userjoe, disallow root login over SSH.
sudo vim /etc/ssh/sshd_config
Flag the following parameter from yes`` to no`.
PermitRootLogin no
Set hostname
The initial server prompt is something like this:
userjoe@li331-187:~$
It can be changed into something more fun, like a greek god's name.
sudo hostnamectl set-hostname apollo
Log out and log in back again. The prompt now reads:
userjoe@apollo:~$
Set local time
By default, Linux's image will be set to UTC time (Greenwich Mean Time). Change this to the local server time with:
sudo dpkg-reconfigure tzdata
Pick US and Pacific-New,
Current default time zone: 'US/Pacific-New'
Local time is now: Fri Apr 7 21:51:25 PDT 2023.
Universal Time is now: Sat Apr 8 04:51:25 UTC 2023.
Set up passwordless SSH login
Generate public and private SSH key pair on the local machine (or your local server, or whatever server you use as the entry point to SSH into other remote machine).
ssh-keygen
Do not use a passphrase
Just click space bar twice to skip the creation of a passphrase.
The key pair will be generated and saved in ~/.ssh as:
id_rsa_apolloid_rsa_apollo.pub
Copy the public key to server apollo using SSH.
cat ~/.ssh/id_rsa_apollo.pub | ssh userjoe@12.34.56.78 "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys"
Do not ever copy private key to another remote machine
Configure SSH
On the local machine, edit the SSH configuration file.
vim ~/.ssh/config
Add this entry to the file
host apollo
HostName 12.34.56.78
User userjoe
IdentityFile ~/.ssh/id_rsa_apollo
Now, instead of using the clumsy ssh userjoe@12.34.56.78, do this
ssh apollo
Set personal preferences
On the server apollo, open up configuration file .bashrc and add a few lines for personal preferences.
# use PS1 to change the format of the prompt
# PS1='[\u@\h \W]\$ ' # Default
# \A: the current time in 24-hour HH:MM: format
# \w: the current working directory
# \u: the username of the current user
# \#: the command number of this command
# \h: the hostname up to the first '.'
# display format = absolute path + time + command number + user@hostname
export PS1="\[\e[0;36m\]\w\[\e[m\] \[\e[0;33m\]\A\[\e[m\] \[\e[0;34m\][\#]\[\e[m\] \[\e[0;32m\]\u\[\e[m\]@\[\e[0;35m\]\h\[\e[m\] \[\e[0;37m\]$ \[\e[m\]"
alias lsl="ls -la | awk '{k=0;for(i=0;i<=8;i++)k+=((substr(\$1,i+2,1)~/[rwx]/)*2^(8-i));if(k)printf(\"%0o \",k);print}'"
alias rm="rm -i"
Then refresh the terminal instance for the new configuration to take effect.
source .bashrc
These are some of the most basic steps to initialize a new server instance for ease of use. Rock on!
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