Ubuntu

Description

Ubuntu is a Linux distribution derived from Debian and composed mostly of free and open-source software. Ubuntu is officially released in multiple editions: Desktop, Server, and Core for Internet of things devices and robots.

References

Canonical Ubuntu

Installation

Description

This details the installation process for Ubuntu as a server on a virtual machine.

References

Ubuntu 20.04.6 LTS (Focal Fossa)

Minimum Requirements

Tip

It is recommended to use the minimum requirements for a base VM and expand them as needed for extended VMs.

CPU: 1
Memory: 1GB
Storage: 10GB

Steps

Go through the installation wizard as per usual.
In the Profile setup section:
- Your name: Set a display name suitable for your homelab
- Your server's name: Set a unique name for said server without the domain name (i.e. ubuntu-server)
- Pick a username: Set a username suitable for your homelab
- Choose a password: Set a secure, minimum 12 character password
- Confirm your password: Confirm the password you have set
In the SSH Setup section:
- Install OpenSSH server: Enabled
- Import SSH identity: Disabled
Complete the installation.

Configuration

Description

This details some recommended configuration options for Ubuntu as a server.

Base VM

Perform a full system upgrade on the system using apt.
Install the following packages using apt:
- curl
- git
- htop
- nano
- net-tools
- openssh-server
- python3
- python3-pip
- wget
Install packages required by your hypervisor using apt:
- ESXi: open-vm-tools
- Proxmox: qemu-guest-agent
  
  [!TIP]
  On Proxmox, you may also need to enable the qemu-guest-agent service yourself.
Clean up the system using apt to recover some storage space.
Enable the SSH service (if it is not already enabled).
Copy over your public SSH key(s) to the system.
Decide on a new SSH port (i.e. 2222) to replace the default port, 22.
Update the VM's SSH configuration, which includes:
- Changing the default SSH port to a new port (i.e. 2222).
- Disabling root login via SSH.
- Disabling password authentication via SSH.
  
  [!WARNING]
  Make sure you have copied over your public SSH key(s) to the system before applying this change!
Set up the VM firewall (UFW):
- Enable the firewall.
- Check the firewall status to ensure it is active and no rules have been configured.
- Allow the connection to the new SSH port (i.e. 2222) using the tcp protocol.
For systems running cloud-init (i.e. on a Raspberry Pi), password prompts may not be required when using sudo by default.
- To fix this, check the content of the /etc/sudoers file:
```
sudo cat /etc/sudoers
```
- Identify whether the following line is found in the file and not commented:
```
%sudo   ALL=(ALL:ALL) ALL
```
  If it is not found, add the line to the end of the file accordingly. Likewise, uncomment the line if it is commented.
- Now, check for a configuration file in the /etc/sudoers.d/ directory that is responsible for the current behaviour:
```
sudo ls -l /etc/sudoers.d/
```
  Sample output:
```
total 8
-r--r----- 1 root root 149 Apr 21  2022 90-cloud-init-users
-r--r----- 1 root root 958 Feb  3  2020 README
```
  In this example, the configuration file is 90-cloud-init-users.
- Update the configuration file (i.e. 90-cloud-init-users) to change this behaviour:
```
sudo nano /etc/sudoers.d/90-cloud-init-users
```
  Sample configuration:
```
# Created by cloud-init v. 22.2-0ubuntu1~20.04.3 on Thu, 21 Apr 2022 12:54:58 +0000

# User rules for <user>
<user> ALL=(ALL) NOPASSWD:ALL
```
  Comment the line with the NOPASSWD:ALL option to prevent it from allowing the <user> user from using sudo without a password:
```
  # Created by cloud-init v. 22.2-0ubuntu1~20.04.3 on Thu, 21 Apr 2022 12:54:58 +0000
  
  # User rules for <user>
- <user> ALL=(ALL) NOPASSWD:ALL
+ #<user> ALL=(ALL) NOPASSWD:ALL
```
  Alternatively, if you think it is safe, you may also delete the configuration file entirely:
```
sudo rm -f /etc/sudoers.d/90-cloud-init-users
```
- Finally, disable cloud-init completely to prevent this from being overwritten:
```
sudo touch /etc/cloud/cloud-init.disabled
```
  Alternatively, disable cloud-init from managing any sudo configuration for the user:
```
sudo nano /var/lib/cloud/instance/user-data.txt
```
  Look for the NOPASSWD:ALL option and comment or remove it:
```
- sudo: ALL=(ALL) NOPASSWD:ALL
+ #sudo: ALL=(ALL) NOPASSWD:ALL
```
Clear the VM's Bash history:
```
history -c
cat /dev/null > ~/.bash_history && history -c && history -w
```
[!NOTE]
There should be no other active sessions on the VM while doing this.
Reboot the VM to apply all changes:
```
sudo reboot now
```

Extended VM

These configuration options are expected to be applied on top of the changes that were made to the base VM inherited by the extended VM:

Perform a full system upgrade on the system using apt, especially if it's been a while since the base VM was last upgraded.
Set a static IP address and update the DNS server for the VM.
Update the system hostname.

Networking

Description

This details the process of updating certain networking configurations on the system.

References

How to Configure Static IP Address on Ubuntu 20.04

Set Static IP and Update DNS

This details the process of setting a static IP address and updating the DNS server on a system.

Ensure the system's network configuration is not provisioned by cloud-init:
```
ls -l /etc/netplan/*-cloud-init.yaml
```
If the output is not empty, then the system is provisioned by cloud-init and needs to be disabled.
To disable cloud-init from managing the system's network configuration:
```
sudo nano /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg
```
Add and save the following configuration to the file:
```
network: {config: disabled}
```

Backup the existing network configuration file, if available:

sudo cp /etc/netplan/00-installer-config.yaml /etc/netplan/00-installer-config.yaml.bak

Determine the name of the active network interface on the system:

route | grep '^default' | grep -o '[^ ]*$'

Sample output:

enp6s18

Alternatively, you may also use the following command:

ip link

Sample output:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp6s18: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether fg:LA:Og:mQ:LQ:7Q brd ff:ff:ff:ff:ff:ff

In this example, enp6s18 is the name of the active network interface.

Update or create the network configuration file:
```
sudo nano /etc/netplan/00-installer-config.yaml
```

Update the configuration as such:

Original configuration which uses DHCP to dynamically assign an IP address:

network:
  ethernets:
    <network-interface>:
      dhcp4: true
  version: 2

Make the following changes:

network:
  ethernets:
    <network-interface>:
+     addresses: [<ip-address>/24]
-     dhcp4: true
+     dhcp4: false
+     nameservers:
+       addresses: [<dns1>,<dns2>]
  version: 2

The following is an example of the updated configuration:

network:
  ethernets:
    enp6s18:
      addresses: [192.168.0.106/24]
      dhcp4: false
      nameservers:
        addresses: [1.1.1.1,8.8.8.8]
  version: 2

Save all changes made to the file and apply the new configuration:
```
sudo netplan apply
```

Update Hostname

This details the simple process of updating system's hostname:

Update the system's hostname using hostnamectl:
```
sudo hostnamectl set-hostname "<hostname>.<domain>"
```
As an example, if the new <hostname> is ubuntu-1 and the <domain> is example.com:
```
sudo hostnamectl set-hostname "ubuntu-1.example.com"
```

(Optional) If you intend to update the system's hosts file, Ensure the system's hosts file is not managed by cloud-init:

cat /etc/hosts

If the start of the hosts file has the following disclaimer, then it is likely managed by cloud-init and needs to be disabled:

# Your system has configured 'manage_etc_hosts' as True.
# As a result, if you wish for changes to this file to persist
# then you will need to either
# a.) make changes to the master file in /etc/cloud/templates/hosts.debian.tmpl
# b.) change or remove the value of 'manage_etc_hosts' in
#     /etc/cloud/cloud.cfg or cloud-config from user-data
#

To disable cloud-init completely:

sudo touch /etc/cloud/cloud-init.disabled

(Optional) Update the system's hosts file:

sudo nano /etc/hosts

Sample of the original hosts file:

127.0.0.1 localhost
127.0.1.1 ubuntu-server

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

As an example, update the hostname from ubuntu-server to ubuntu-1:

127.0.0.1 localhost
- 127.0.1.1 ubuntu-server
+ 127.0.1.1 ubuntu-1

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Reboot the VM to apply the changes:
```
sudo reboot now
```

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

ubuntu.md

ubuntu.md

Ubuntu

Description

Directory

References

Installation

Description

References

Minimum Requirements

Steps

Configuration

Description

Base VM

Extended VM

Networking

Description

References

Set Static IP and Update DNS

Update Hostname

Files

ubuntu.md

Latest commit

History

ubuntu.md

File metadata and controls

Ubuntu

Description

Directory

References

Installation

Description

References

Minimum Requirements

Steps

Configuration

Description

Base VM

Extended VM

Networking

Description

References

Set Static IP and Update DNS

Update Hostname