Linux

Docker

Docker

Updating container using docker-compose

To list all containers:

Docker

Setting up Apache Guacamole using Docker

Visit: https://github.com/boschkundendienst/guacamole-docker-compose

Follow instructions which in short are:

  1. git clone "https://github.com/boschkundendienst/guacamole-docker-compose.git"
  2. cd guacamole-docker-compose
  3. Edit docker-compose.yml to suite your environment
  4. ./prepare.sh
  5. docker compose up -d

If you want to add TOTP then do the following:

  1.  In your docker-compose.yml file add
    • Environment variable: GUACAMOLE_HOME=/config/guacamole
    • Mount ./guacamole:/config/guacamole
  2. Create in your docker directory

After adding the above extension, restart the container.

 

Docker

Troubleshooting Docker

Check Environment Variables Inside the Container: 

sudo docker exec -it container-name env

Review Logs:

sudo docker logs container-name
sudo docker-compose up -d && sudo docker-compose logs -f

 

Docker

Paperless: ProtonMail Bridge

Source code: shenxn/protonmail-bridge-docker: ProtonMail IMAP/SMTP Bridge Docker container (github.com)

Change to the Paperless docker directory

sudo docker compose down
sudo docker run --rm -it -v protonmail:/root shenxn/protonmail-bridge init

Enter "login" to connect the ProtonMail account. Once complete, type "info" to get the login details that will be used in the Paperless mail interface.

Exit the instance (using control-c if necessary).

Bring paperless up again.

sudo docker compose up -d

Configure and test the mail settings

image.png

Docker

Your URLS

 

version: '3.1'

services:

  yourls:
    image: yourls
    restart: always
    ports:
      - 8080:80
    volumes:
      - /home/sysadmin/yourls:/var/www/html
    environment:
      YOURLS_DB_PASS: dbpwd
      YOURLS_SITE: https://192.168.20.40:8080/
      YOURLS_USER: osgadmin
      YOURLS_PASS: yourlspwd

  mysql:
    image: mysql
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: dbpwd
      MYSQL_DATABASE: yourls
Docker

Cloudflare

version: "3.9"
services:

  tunnel:
    container_name: cloudflared-tunnel
    image: cloudflare/cloudflared
    restart: unless-stopped
    command: tunnel run
    environment:
      - TUNNEL_TOKEN=token................


Docker

Updating a docker container running on QNAP using SSH

SSH enabled on your QNAP NAS

1. Identify the Container and Image Name

Option A: Using Container Station GUI

  1. Open Container Station.

  2. Navigate to the Containers tab.

  3. Click on the target container to view details.

  4. Locate the Image field — this is the image used (e.g., linuxserver/nextcloud:latest).

Option B: Using SSH

ssh admin@<your-nas-ip> docker ps

Copy the container name (e.g., nextcloud) and run:

docker inspect --format='{{.Config.Image}}' <container-name>

This returns the image name, e.g.:

linuxserver/nextcloud:latest

2. Back Up Container Volumes (Optional but Recommended)

Check volume mappings:

docker inspect <container-name> | grep -A 10 "Mounts"

Back up the volume path if necessary. For example, if a volume is mounted to /share/Container/nextcloud/config, back that up using QNAP File Station or rsync.

3. Pull the Latest Docker Image

docker pull <image-name>

Example:

docker pull linuxserver/nextcloud:latest

4. Stop and Remove the Old Container

docker stop <container-name> docker rm <container-name>

Example:

docker stop nextcloud docker rm nextcloud

⚠️ This does not delete the image or volume data.

5. Recreate the Container with Same Settings

Get Existing Settings (Ports, Volumes, Env Vars)

Use:

docker inspect <container-name>

Note the following:

Re-run the Container

Example:

docker run -d \ --name nextcloud \ -e PUID=1000 \ -e PGID=1000 \ -e TZ=Europe/London \ -p 8080:80 \ -v /share/Container/nextcloud/config:/config \ -v /share/Container/nextcloud/data:/data \ linuxserver/nextcloud:latest

Replace volume paths, ports, and environment variables based on what you had before.

6. Verify Everything Works

7. (Optional) Remove Old Images

List unused images:

docker images

Clean up dangling images:

docker image prune

Or remove a specific old image manually:

docker rmi <image-id>
Bonus: Automatically Extract and Re-run a Container

To automatically generate a docker run command:

docker run --rm \ -v /var/run/docker.sock:/var/run/docker.sock \ red5d/docker-autocompose <container-name> > recreate-container.yml

Then review or convert the output back into a run command.

Resyncing ISO location on XCP-NG server

Managing Disks and Space

Disk Info

df -h : displays the information of device name, total blocks, total disk space, used disk space, available disk space and mount points on a file system (-h displays output in readable format).

sudo du -mxsh * | sort -n : The du command summarises the disk usage of each file.

mount | grep root : displays mount points with "root" in them
sudo pvdisplay : display attributes of a physical volume
sudo lvdisplay : display attributes of a logical volume

Disk restructuring & resizing (LVM)

Other

sudo yum clean all : cleans cache

How to batch-resize images using ImageMagick

open terminal and cd into the directory containing your photos and execute below command

mkdir photos-Optimized;for photos in *.JPG;do convert -verbose "$photos" -quality 85% -resize 1600x900 ./photos-Optimi

Voila! Now you have successfully batch resized/compressed images, You can see the optimized images in the photos-Optimized directory.

Taken from https://linuxsuperuser.com/batch-resize-compress-photos-linux/

How to find a file containing a particular text string

Search all subfirectories recursively

grep -r "redeem reward" /home/tom/

To display only fines names, add -H option, or

$ grep -H -R vivek /etc/* | cut -d: -f1

To ignore case, add -i option.

How do I set permissions on all directories and files on a Linux system?

To change all the directories to 755 (drwxr-xr-x):

find /opt/lampp/htdocs -type d -exec chmod 755 {} \;

To change all the files to 644 (-rw-r--r--):

find /opt/lampp/htdocs -type f -exec chmod 644 {} \;

How do you use (run/install) an AppImage?

AppImages do not need to be installed. They are a self-contained app that simply needs to be made executable and then run.

As nothing is actually installed, it is good idea to move the downloaded APPIMAGE file to a folder of your choice before creating any shortcut link to it.  For my Fedora install I use /usr/local/share/filename-directory. If necessary I will also save the shortcut image here.

Download the AppImage and then make it exscutable as follows:

$ chmod a+x Filename.AppImage

Now run the application as follows:

$ ./Filename.AppImage

When first run, some AppImage applications will ask if a desktop shortcut should be created.

If a shortcut is not created, this can be done manaually using your text editor of choice. In my Fedora install this is done here: ~/.local/share/applications/

Connecting Ubuntu Desktop 22.04 to a Meraki VPN

Add repository for installing network-manager-l2tp

sudo add-apt-repository ppa:nm-l2tp/network-manager-l2tp
sudo apt-get update

Install network-manager-l2tp

sudo apt-get install network-manager-l2tp
sudo apt-get install network-manager-l2tp-gnome

Configure the network

Turn off the xl2tpd service

sudo systemctl stop xl2tpd

and prevent it from starting again on reboot

sudo systemctl disable xl2tpd.

You should now be able to connect to the VPN.

 


Changing VM disk size

Change the size in XoA.

Run lsblk to check it is there.

Boot to GParted and resize partition.

Then

Kiosk Machine

This is a work in progress i.e. I am starting with a locked-down account and working towards a final kiosk deployment.

Two scripts will be created in the process and can be stored in /usr/local/bin.

I am trying to achieve this using PoPOS! with Firefox as the default browser, using duckduckgo as the start-up page and default search engine. The duckduckgo Firefox extension is also installed.

Create a script to run Firefox in full screen mode, opening duckduckgo's homepage in private mode.

I also set the Firefox settings so that no passwords are saved and everything is cleared on exit. 

#!/bin/bash
firefox -private-window  "https://www.duckduckgo.com" &
while ! xdotool search --onlyvisible --class "firefox"; do
    sleep 1
done
xdotool key F11 #xdotool needs to ne installed for this to work

To run the script at login, login as the default user, press Alt + F2 and run gnome-session-properties.
Click on “Add”, name browse to the script and save.

Have the laptop reboot every 10min

#!/bin/bash

# Wait for keyboard or mouse activity - I still need to try this
inotifywait -e modify /dev/input/event* & #install inotify-tools

# Idle time in milliseconds (10 minutes)
IDLE_TIME=$((10 * 60 * 1000))

while true; do
    idle=$(xprintidle)
    if [ "$idle" -ge "$IDLE_TIME" ]; then
        shutdown -r
    fi
    sleep 60
done

Also make this script to run at login using gnome-session-properties.

Both the above scripts need to be made executable.

chmod +x filename.sh

Using OverlayRoot  any changes will be lost when the system reboots.

sudo apt-get install overlayroot

then

sudo nano /etc/overlayroot.conf

and add

overlayroot="tmpfs"

Now reboot.

To disable overlayroot, comment out the above line

#overlayroot="tmpfs"

and then run

sudo update-initramfs -u

Now reboot

XenOrchestra Update

Change to the XenOrchestraInstallerUpdater dirctory and run

 sudo ./xo-install.sh --update

 

Managing Login Sessions

List sessions

loginctl list-sessions

Kill a session

loginctl terminate-session <session>

Lock session

loginctl lock-session