install gui on ubuntu

apt-get update

 sudo apt install ubuntu-desktop

Xrdp on Ubuntu 20.04

 installed Ubuntu 20.04 and then installed xrdp. Whenever i tried to connect, either from another Ubuntu 20.04 box using either xfreerdp or krdc, or from a Mac, a black screen would show up, and then immediately disconnect. i made sure i did not have any other sessions on the server going on at the same time.

4

1. Remove previously installed xrdp:

$ sudo systemctl disable xrdp
$ sudo systemctl stop xrdp

$ sudo apt purge xrdp
$ sudo apt purge xserver-xorg-core
$ sudo apt purge xserver-xorg-input-all
$ sudo apt purge xorgxrdp

2. Re-install xrdp & required packages:

$ sudo apt install xrdp
$ sudo apt install xserver-xorg-core
$ sudo apt install xserver-xorg-input-all
$ sudo apt install xorgxrdp

i installed xrdp and xorgxrdp from deb files from google and worked

You also need to grant access to the /etc/ssl/private/ssl-cert-snakeoil.key file for xrdp user. It is available to members of the ssl-cert group by default.

$ sudo adduser xrdp ssl-cert           # add xrdp into ssl-cert group

$ sudo systemctl start xrdp            # start xrdp service
$ systemctl is-active xrdp             # check xrdp state
...
active

$ sudo systemctl enable xrdp           # start xrdp on system start

3. Reboot system:

$ sudo reboot

Err:1 http://asi-fs-l.contabo.net/ubuntu focal/universe amd64 xrdp amd64 0.9.12-1
  Temporary failure resolving 'asi-fs-l.contabo.net'
Err:2 http://asi-fs-l.contabo.net/ubuntu focal/universe amd64 xorgxrdp amd64 1:0.2.12-1
  Temporary failure resolving 'asi-fs-l.contabo.net'
E: Failed to fetch http://asi-fs-l.contabo.net/ubuntu/pool/universe/x/xrdp/xrdp_0.9.12-1_amd64.deb  Temporary failure resolving 'asi-fs-l.contabo.net'
E: Failed to fetch http://asi-fs-l.contabo.net/ubuntu/pool/universe/x/xorgxrdp/xorgxrdp_0.2.12-1_amd64.deb  Temporary failure resolving 'asi-fs-l.contabo.net'
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
root@vmi1181596:~# systemctl start xorgxrdp
Failed to start xorgxrdp.service: Unit xorgxrdp.service not found.

vi /etc/resolv.conf

8.8.8.8

root@vmi1181596:~# iptables -F
root@vmi1181596:~# adduser mysqli
Adding user `mysqli' ...
Adding new group `mysqli' (1003) ...
Adding new user `mysqli' (1003) with group `mysqli' ...
Creating home directory `/home/mysqli' ...
Copying files from `/etc/skel' ...
New password:
Retype new password:
passwd: password updated successfully
Changing the user information for mysqli
Enter the new value, or press ENTER for the default
        Full Name []: mysqli
        Room Number []:
        Work Phone []:
        Home Phone []:
        Other []:
Is the information correct? [Y/n] Y
root@vmi1181596:~# usermod -aG sudo mysqli

Login as root on ubuntu desktop


Set a root password (may be the same as user password) with sudo passwd root. You'll be asked to type the password twice in case of a typo.
Unlock the root account with sudo passwd -u root.
Edit sudo nano /etc/gdm3/custom.conf, and add the following line under [security]:
AllowRoot=true
Edit sudo nano /etc/pam.d/gdm-password, and comment out the following line by adding a # in front of it, like this:
#auth   required    pam_succeed_if.so user != root quiet_success
Reboot.


Authentication Is Required To Create A Color Profile/Managed Device


You can click Cancel to these popups or enter your password to continue.
But, this article shows how to get rid of them permanently?
This issue is Polkit. Polkit, which is an application authorization framework that captures actions performed by a user to check if the user is authorized to perform certain actions.
Let’s create a new configuration file in /etc/polkit-1/localauthority/50-local.d/45-allow-colord.pkla. This will tell Polkit to continue without requiring the authentication prompt over RDP.
?
sudo nano /etc/polkit-1/localauthority/50-local.d/45-allow-colord.pkla
Paste in the following:
?
[Allow Colord all Users]
Identity=unix-user:*
Action=org.freedesktop.color-manager.create-device;org.freedesktop.color-manager.create-profile;org.freedesktop.color-manager.delete-device;org.freedesktop.color-manager.delete-profile;org.freedesktop.color-manager.modify-device;org.freedesktop.color-manager.modify-profile
ResultAny=no
ResultInactive=no
ResultActive=yes
Save and exit.
Now reboot Ubuntu and try logging in again over RDP / Windows Remote Desktop and the popups should be gone.