Developer VPS Box Setup¶

Credits : Robert Kiraly

Overview¶

This text file documents one possible approach to the setup of a Debian 10 developer’s box.

This is a flexible guide as opposed to a single fixed procedure. The assumption is that the user is a developer who is able to decide which steps to take and how to tweak them.

This guide can be used to create boxes that operate in an optimum manner and are fully-loaded with useful software (including non-Debian extras).

Unless you are an expert, this guide should not be used with existing boxes, especially in cases where bricking would be a serious issue.

Due to oddities in how some VPS hosts set up boxes on their end, there is a possibility that use of this guide will lead to inability to boot VPSes.

This guide can be used in the following contexts :

• The box may be a server but this is not required
• The box may be headless or it may run XOrg
• Some features are for AMD64 system only
• However, Raspberry Pi’s may work
• CPU: 2x2 or above
• RAM: 8GB or above
• Disk: 40 GB or above (SSD or better is recommended)
• Distro should be based on Debian 10

The box may be a local PC, a dedi box, or a VPS. We’ve tried to allow for all three possibilities, but correction may be needed.

Debian Sid and/or Testing branches may work as well as Buster. However, tweaks may be needed.

Ubuntu branches from the same period as “Buster” may work, to a lesser extent.

If the goal is a headless box, GUI software such as LibreOffice should obviously be skipped. Image and/or other multimedia libraries may be installed regardless.

You should have recieved a directory tree named “setupdoc/” with this file. The directory tree should like this

setupdoc/setupdoc.txt   # This page
setupdoc/files/             # A subdirectory with multiple files

setupdoc/ should be place in /root on the box that you would like to setup.

The steps documented here should be executed as superuser except where otherwise indicated.

Examples of packages and/or features installed :

.NET SDK

rjkbin/* : OldCoder utility scripts.

# OldCoder scripts provided:

# cls           - Clear screen
# cmptree       - Byte-compare two directory trees
# cptime        - Copy file or directory timestamp
# debak         - Delete backup files in current directory
# debaktree     - Delete backup files in current tree
# deext         - Echoes arguments with filename extensions removed
# detab         - Detabs files using a 4-space column width
# epoch         - Display timestamp of a directory or file
# largest       - List largest files in a directory tree
# md5all        - Output MD5 sums for a directory tree
# md5tree       - Relatively powerful MD5 sum manager
# newest        - List newest files in a directory tree
# oldest        - List oldest files in a directory tree
# runhtpdate    - (root only) sync server time by HTTP
# setdos        - Set newlines to DOS format
# setunix       - Set newlines to UNIX format
# tardate       - Set timestamp of a tarball or ZIP file
# trimws        - Trim white space from end of text lines

Upgrade Debian Strech to Buster¶

If the box is running Stretch, upgrade it to Buster as shown below. Other skip this step.

#!/bin/bash -e
sed -e 's/stretch/buster/g' \
    -i /etc/apt/sources.lst || exit 1

apt-get update
apt-get upgrade
apt-get dist-upgrade

Reboot the box,Login and become superuser again. Check distro version again.

cat /etc/os-release

Remove unnecessary packages

apt-get autoremove

Distribution Upgrade¶

These commands update files. They may upgrade the distro within its series (for example: from 10.1 to 10.8) but not to next series. That type of upgrade is a separate process

#!/bin/bash -e
apt-get update
apt-get dist-upgrade

Installing Basic Packages¶

Atleast install these packages.

sudo apt-get install dnsutils joe lynx pbzip2 pigz rlwrap

Installing a number of packages¶

#!/bin/bash -e
cd /root/setupdoc/files/
apt-get install `cat *-dpkg.lst`

Check /etc/shells¶

If the text file /etc/shells doesn’t already contain the following line, add the line : /bin/bash

Note : If dropbear seems to be accepting connections but produces error messages, this issue may be the problem.

Modify /etc/fstab entry for root filesystem¶

NOTE : This step is only for physical boxes and/or dedis. Skip it for VPSes.

1. Replace default for root filesystem with : noatime,errors=remount=ro
2. Execute:

#!/bin/bash -e
cd /etc
cp -ai fstab fstab.000
nano   fstab

Setup dnsmasq¶

#!/bin/bash -e
apt-get install dnsmasq

Replace /etc/dnsmasq.conf and etc/resolv.conf with the copies provided in setupdoc/files. Then execute :

#!/bin/bash -e
chattr +i /etc/resolv.conf
service dnsmasq restart

Note : Subsequently, you won’t be able to edit /etc/resolv.conf unless you run chattr -i on the file first. After edits, run chattr +i on the file again.

To confirm dnsmasq is working, execute this command ;

nslookup bacon.eggs

dnsmasq is a caching DNS server. To flush the cache, restart the dnsmasq service.

Generate a keypair for your server-side user accounts¶

#!/bin/bash -e
rlwrap ssh-keygen -t rsa -b 2048

Do not specify a password for the keypair. Additionally, specify box-specific names such as pi.pubkey and pi.prvkey. The .prvkey file goes on your ssh client boxes. The .pubkey file should be appended to $HOME/.ssh/authorized_keys for your user account on the server box.

If you're using dropbear instead of openssh, skip this part.

Step: If you're using openssh, edit /etc/ssh/sshd_config and set:

MaxStartups 75
UseDNS no

Then execute: service sshd restart

Create directories for utilities¶

#!/bin/bash -e
mkdir -p /opt/minetest/mtbin
mkdir -p /opt/smkbin

Create a text file /etc/profile.d/smkbin.sh containing :

NOTE : Don’t use #!/bin/bash -e here.

for dir in \
    /opt/minetest/mtbin \
    /opt/minetest/smkbin \
    /opt/smkbin
do
    if [ -d $dir ]; then PATH=$dir:$PATH; fi
done

This file needs to be readable, but it doesn’t need to be executable.

Edit secure_path setting in etc/sudoers to prepend directories from preceding scripts which exists.¶

secure_path="/opt/minebest/mtbin:/opt/smkbin:/usr/local/sbin:..."

Log-out and back in.

If you log-in as an ordinary user, execute the following command to become the superuser

sudo bash

You can now add useful scripts and tools to the two new directories.

Set LC_ALL¶

Create a text file /etc/profile.d/lc_all.sh containing:

export LC_ALL=C

File needs to be readable, but not executable.

Set a timezone¶

To list possible time zones, do this : timedatectl list-timezones

For Kolkata timezone in India : timedatectl set-timezone Asia/Kolkata

Replace gzip and bzip2 with faster version¶

We need to save the old versions as some programs may need then

if [ \! -L /bin/gzip ]; then
    mv /bin/gzip{,.000}
    ln -s `which pigz`   /bin/gzip
fi

if [ \! -L /bin/bzip2 ]; then
    mv /bin/bzip2{,.000}
    ln -s `which pbzip2` /bin/bzip2
fi

These two special version are faster for new files, but not neccessarily for existing files.

Adding a ordinary user¶

At this point, add atleast one ordinary user. To do so, execute rlwrap adduser once for each user.

Initially only account name and passwords are important. Other fields can be left empty. The account name needs to be lower-case.

Execute following block for each new-user, Substitute the appropriate name for “sally”

THEM=sally
HOUSE=/home/$THEM
chmod 700 $HOUSE
mkdir -p  $HOUSE/.ssh
chmod 700 $HOUSE/.ssh
touch     $HOUSE/.ssh/authorized_keys
chown -R  $THEM.$THEM $HOUSE

When time permits, you (as admin) or each individual user should append each individual user's public key to the following file. Substitute the appropriate account name for "sally" in each case. /home/sally/.ssh/authorized_keys

Execute the following command once for each user who should have sudo access : usermod -a sally -G sudo.

Optional : Enable sudo w/o password¶

Create a file named 90-cloud-init-users.

touch 90-cloud-init-users
chmod 440 90-cloud-init-users

Put following text in it.

root ALL=(ALL) NOPASSWD:ALL
smk ALL=(ALL) NOPASSWD:ALL

now copy this file to etc/sudoers.d

Warning : This step if not done properly can brick the box!

Also do not edit the file once its in directory. This may also brick the box. Safest way is to edit is somewhere else and then copy result into the directory in question

Set hostname¶

If possible, at this point, you should point the IPV4 for some domain that you control to the Debian box. Note: This doesn't apply if the box isn't on the WAN.

If you have a domain and point it as indicated, set the hostname for the box as follows:

DOMAIN=somedomain.com           # Replace with appropriate domain
hostname $DOMAIN
echo     $DOMAIN > /etc/hostname

Harden Security¶

# vi /etc/ssh/sshd_config

# note these are important, as vps almost every few minutes gets attacked by botnets
# changing port decreases attack surface
# disabling password auth decreases risk of guessing password
# note : you may not worry if you screw up your keys, you can always vnc into the vm from
# cloud providers console and login and fix your box

Port 23415
PasswordAuthentication no

# after that run service sshd restart