Recommendations for extending an image.

[NicolasRouquette]

I would like to extend one of the g3 images to add additional packages.
What are the different ways to do this?

One approach may be cloning the repo and modifying the scripts. This seems non-trivial given the multi-stage process for building the g3 image.

Another approach is to use a Dockerfile like this:

FROM accetto/ubuntu-vnc-xfce-firefox-g3:20.04

### switch to the root user to be able to install new packages
USER root

RUN apt-get update
RUN apt-get install -y software-properties-common

I am surprised that when I start this image with the --debug flag, I get permission errors that do not happen if I start the original g3 image:

# Open browser at: http:localhost:6901/vnc.html
Script: /dockerstartup/startup.sh
${HOME}=/home/headless
ls -la /
total 76
drwxr-xr-x   1 root root 4096 May 18 18:15 .
drwxr-xr-x   1 root root 4096 May 18 18:15 ..
-rwxr-xr-x   1 root root    0 May 18 18:15 .dockerenv
lrwxrwxrwx   1 root root    7 Apr 12 02:03 bin -> usr/bin
drwxr-xr-x   2 root root 4096 Apr 15  2020 boot
drwxr-xr-x   5 root root  360 May 18 18:15 dev
drwxr-xr-x   1 root root 4096 May  2 11:47 dockerstartup
drwxrwxr-x   1  984  980 4096 May 18 18:15 etc
drwxr-xr-x   1 root root 4096 May  2 11:47 home
lrwxrwxrwx   1 root root    7 Apr 12 02:03 lib -> usr/lib
lrwxrwxrwx   1 root root    9 Apr 12 02:03 lib32 -> usr/lib32
lrwxrwxrwx   1 root root    9 Apr 12 02:03 lib64 -> usr/lib64
lrwxrwxrwx   1 root root   10 Apr 12 02:03 libx32 -> usr/libx32
drwxr-xr-x   2 root root 4096 Apr 12 02:03 media
drwxr-xr-x   2 root root 4096 Apr 12 02:03 mnt
drwxr-xr-x   2 root root 4096 Apr 12 02:03 opt
dr-xr-xr-x 642 root root    0 May 18 18:15 proc
drwx------   2 root root 4096 Apr 12 02:06 root
drwxr-xr-x   1 root root 4096 May 18 17:50 run
lrwxrwxrwx   1 root root    8 Apr 12 02:03 sbin -> usr/sbin
drwxr-xr-x   2 root root 4096 Apr 12 02:03 srv
dr-xr-xr-x  11 root root    0 May 18 18:15 sys
drwxrwxrwt   1 root root 4096 May 18 17:50 tmp
drwxrwxr-x   1  984  980 4096 Feb 28 15:37 usr
drwxr-xr-x   1 root root 4096 Apr 12 02:06 var
drwxr-xr-x   3 root root 4096 May 18 18:15 workspaces
ls -ls /etc/passwd /etc/group
4 -rw-rw-r-- 1 root root  557 May 18 17:50 /etc/group
4 -rw-rw-r-- 1 root root 1287 May 18 17:50 /etc/passwd
ls -la /home
total 12
drwxr-xr-x 1 root root 4096 May  2 11:47 .
drwxr-xr-x 1 root root 4096 May 18 18:15 ..
drwxr-xr-x 1 root root 4096 May  2 11:47 headless
ls -la /home/headless
total 32
drwxr-xr-x 1 root root 4096 May  2 11:47 .
drwxr-xr-x 1 root root 4096 May  2 11:47 ..
drwxr-xr-x 1 root root 4096 May  2 11:47 .config
drwxr-xr-x 1 root root 4096 May  2 11:47 Desktop
drwxr-xr-x 1 root root 4096 May  2 11:47 firefox.plus
-rw-r--r-- 1 root root  458 May  2 11:28 readme-firefox-plus.md
-rw-r--r-- 1 root root  185 May  2 11:28 readme.md
drwxr-xr-x 1 root root 4096 May  2 11:47 tests
ls -la .
total 32
drwxr-xr-x 1 root root 4096 May  2 11:47 .
drwxr-xr-x 1 root root 4096 May  2 11:47 ..
drwxr-xr-x 1 root root 4096 May  2 11:47 .config
drwxr-xr-x 1 root root 4096 May  2 11:47 Desktop
drwxr-xr-x 1 root root 4096 May  2 11:47 firefox.plus
-rw-r--r-- 1 root root  458 May  2 11:28 readme-firefox-plus.md
-rw-r--r-- 1 root root  185 May  2 11:28 readme.md
drwxr-xr-x 1 root root 4096 May  2 11:47 tests
mkdir: cannot create directory '/home/headless/.vnc': Permission denied
/dockerstartup/vnc_startup.rc: line 72: /home/headless/.vnc/passwd: No such file or directory
chmod: cannot access '/home/headless/.vnc/passwd': No such file or directory
/dockerstartup/vnc_startup.rc: line 80: /home/headless/.vnc/config: No such file or directory
Starting VNC
vncserver :1 &> /dockerstartup/vnc.log
VNC server started on display ':1' and TCP port '5901'
Connect via VNC viewer with 172.17.0.2:5901
/dockerstartup/vnc_startup.rc: line 114: /dockerstartup/vnc.log: Permission denied
Starting noVNC
/usr/libexec/noVNCdim/utils/novnc_proxy --vnc localhost:5901 --listen 6901  &> /dockerstartup/novnc.log
noVNC started on TCP port '6901'
Connect via web browser
/dockerstartup/vnc_startup.rc: line 142: /dockerstartup/novnc.log: Permission denied
Killing last background PID '24'
/dockerstartup/startup.sh: line 25: kill: (24) - No such process
Killing blocking PID '23'

Can someone explain what is the proper way to do this?

[NicolasRouquette]

In the above, the problem originates from this line:

RUN apt-get install -y software-properties-common

Without it, the image seems to work properly.
With it, the image exhibits the permission problem described above.

[accetto]

Hello @NicolasRouquette,

I'm sorry, but I've completely missed your question. :(

However, I'm not able to reproduce the issue.

Providing more information would help:

1. How do you create your container? Can you provide the command line?
2. Have you bound any volumes?
3. What is your environment?

This is how I've tested it.

Environment: Linux Debian 11 with Docker Desktop installed (v4.20.0).

I've built a new image dev/issue-48 using the Dockerfile you've provided above.

Then I've created a container using the following command:

docke run --rm -it -P dev/issue-48 --debug

This is the output I've got:

Script: /dockerstartup/startup.sh
${HOME}=/home/headless
ls -la /
total 72
drwxr-xr-x   1 root root 4096 Jun  4 09:46 .
drwxr-xr-x   1 root root 4096 Jun  4 09:46 ..
-rwxr-xr-x   1 root root    0 Jun  4 09:46 .dockerenv
lrwxrwxrwx   1 root root    7 Apr 12 02:03 bin -> usr/bin
drwxr-xr-x   2 root root 4096 Apr 15  2020 boot
drwxr-xr-x   5 root root  360 Jun  4 09:46 dev
drwxr-xr-x   1 root root 4096 Jun  3 10:19 dockerstartup
drwxrwxr-x   1  984  980 4096 Jun  4 09:46 etc
drwxr-xr-x   1 root root 4096 Jun  3 10:18 home
lrwxrwxrwx   1 root root    7 Apr 12 02:03 lib -> usr/lib
lrwxrwxrwx   1 root root    9 Apr 12 02:03 lib32 -> usr/lib32
lrwxrwxrwx   1 root root    9 Apr 12 02:03 lib64 -> usr/lib64
lrwxrwxrwx   1 root root   10 Apr 12 02:03 libx32 -> usr/libx32
drwxr-xr-x   2 root root 4096 Apr 12 02:03 media
drwxr-xr-x   2 root root 4096 Apr 12 02:03 mnt
drwxr-xr-x   2 root root 4096 Apr 12 02:03 opt
dr-xr-xr-x 253 root root    0 Jun  4 09:46 proc
drwx------   2 root root 4096 Apr 12 02:06 root
drwxr-xr-x   1 root root 4096 Jun  4 09:21 run
lrwxrwxrwx   1 root root    8 Apr 12 02:03 sbin -> usr/sbin
drwxr-xr-x   2 root root 4096 Apr 12 02:03 srv
dr-xr-xr-x  13 root root    0 Jun  4 09:46 sys
drwxrwxrwt   1 root root 4096 Jun  4 09:21 tmp
drwxrwxr-x   1  984  980 4096 Feb 28 15:37 usr
drwxr-xr-x   1 root root 4096 Apr 12 02:06 var
ls -ls /etc/passwd /etc/group
4 -rw-rw-r-- 1 root root  557 Jun  4 09:21 /etc/group
4 -rw-rw-r-- 1 root root 1287 Jun  4 09:21 /etc/passwd
ls -la /home
total 12
drwxr-xr-x 1 root root 4096 Jun  3 10:18 .
drwxr-xr-x 1 root root 4096 Jun  4 09:46 ..
drwxr-xr-x 1 root root 4096 Jun  3 10:19 headless
ls -la /home/headless
total 32
drwxr-xr-x 1 root root 4096 Jun  3 10:19 .
drwxr-xr-x 1 root root 4096 Jun  3 10:18 ..
drwxr-xr-x 1 root root 4096 Jun  3 10:19 .config
drwxr-xr-x 1 root root 4096 Jun  3 10:19 Desktop
drwxr-xr-x 1 root root 4096 Jun  3 10:19 firefox.plus
-rw-r--r-- 1 root root  458 Jun  3 10:07 readme-firefox-plus.md
-rw-r--r-- 1 root root  185 Jun  3 10:07 readme.md
drwxr-xr-x 1 root root 4096 Jun  3 10:19 tests
ls -la .
total 32
drwxr-xr-x 1 root root 4096 Jun  3 10:19 .
drwxr-xr-x 1 root root 4096 Jun  3 10:18 ..
drwxr-xr-x 1 root root 4096 Jun  3 10:19 .config
drwxr-xr-x 1 root root 4096 Jun  3 10:19 Desktop
drwxr-xr-x 1 root root 4096 Jun  3 10:19 firefox.plus
-rw-r--r-- 1 root root  458 Jun  3 10:07 readme-firefox-plus.md
-rw-r--r-- 1 root root  185 Jun  3 10:07 readme.md
drwxr-xr-x 1 root root 4096 Jun  3 10:19 tests
Starting VNC
vncserver :1 &> /dockerstartup/vnc.log
VNC server started on display ':1' and TCP port '5901'
Connect via VNC viewer with 172.17.0.2:5901
Starting noVNC
/usr/libexec/noVNCdim/utils/novnc_proxy --vnc localhost:5901 --listen 6901  &> /dockerstartup/novnc.log
noVNC started on TCP port '6901' 
Connect via web browser

I've also checked inside the container that the package software-properties-common is installed:

apt list --installed | grep software-properties-common

The output:

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

software-properties-common/focal-updates,now 0.99.9.11 all [installed]

Do you still experience the issue?

Regards,
accetto

[accetto]

Hallo @NicolasRouquette,

I believe that my answer to the issue #51 applies also to this one.

Regards,
accetto

[accetto]

Hallo @NicolasRouquette,

I believe that my answer to the issue #51 applies also to this one.

Regards,
accetto

[accetto]

The new User guide contains a section about using Docker Compose with my images. First examples are already included and more are still to come. Therefore I'm closing this discussion. Please use the Issues of the User guide project for feedback.