Homelab, Linux, JS & ABAP (~˘▾˘)~

[NAS] OpenSource NAS-Systeme & Self-hosting Lösungen


TrueNAS Core (FreeBSD) / TrueNAS Scale (Debian)
XigmaNAS (FreeBSD/FreeNAS, ehemals NAS4FREE)
OpenMediaVault (Debian)
Xpenology (bootloader for Synology’s DSM)
OmniOS Community Edition (Illumos) mit Napp-IT
Rockstor (CentOS)

Self-hosting / Hypervisor

YunoHost (Debian)
Proxmox (Debian)
OmniOS Community Edition (Illumos)
SmartOS (Illumos)
Danube Cloud (SmartOS)
XCP-ng (XenServer / heute Citrix Hypervisor)

[NGINX] Monitoring Nginx using Netdata

Recently I saw this tutorial about monitoring Nginx with Netdata and tried it by myself. I have running Netdata on my Proxmox Host and Nginx inside LXC. So I could skip step 1 and 2 of the tutorial. Since I’m using the super simple nginx-proxy-manager, which comes as docker deployment, it took me some minutes to figure out, how to enable the Nginx ‘stub_status‘ module (which is step 3 of the tutorial). Here’s what I did.

SSH into the LXC where the Nginx Docker is running. Look up the nginx container name (root_app_1) and open a shell in the running container.

docker ps
docker exec -it root_app_1 /bin/bash

Check if the ‘stub_module‘ is already enabled. The following command should return: with-https_stub_status_module
I got it from here.

nginx -V 2>&1 | grep -o with-https_stub_status_module

Next add a location to the nginx ‘server {}‘ block in the default config, to make it reachable via Netdata. The tutorial goes to ‘/etc/nginx/sites-available/default‘, another tutorial is editing ‘/etc/nginx/nginx.conf‘, but I found the default config in ‘/etc/nginx/conf.d/default.conf’.

nano /etc/nginx/conf.d/default.conf

If nano is not installed (bash: nano: command not found), just install it. Get more information here or here.

apt update 
apt install nano -y

Insert the new location in the server { listen 80; …..} block. In my case I have running Netdata on my Proxmox host, so i added localhost and my Proxmox ip.

  location /nginx_status {
	allow; #only allow requests from pve
	allow;	  #only allow requests from localhost
	deny all;		  #deny all other hosts	

Save, exit your docker container and restart it.

docker restart root_app_1

SSH into Proxmox and check with curl, if you able to reach the new nginx location.

For the last step Configure Netdata to Monitor Nginx (step 4) , just follow the Netdata Wiki. Place a new file called nginx.conf on your Netdata host.

nano /etc/netdata/python.d/nginx.conf

Because Netdata is not running local, use ‘remote‘ following the url, instead of local and localhost.

update_every : 10
priority     : 90100

  url     : ''

Restart Netdata and your are done.

sudo systemctl restart netdata

[Shell] Delete a folder and its content

If you downloaded a series there are often folders for each episode. Each episode folder often includes another folder called “Sample” with a short demo video file.

Series -> Season 01 -> Episode 01 -> Sample -> sample.mkv

To get rid of these you can use the “find” and “rm” command. To remove each sample folder with its content you have to use the remove command with an “-r”.

find -name "Sample" -exec rm -r "{}" \;

[Nextcloud] Installing Collaboraoffice in LXC

Both, Nextcloud and Collabora, are recommending the Docker installation for Collaboraoffice (here and here). But I wasn’t able to get the Collabora Docker Image running succesfully inside an Debian Buster LXC. There were appearing some errors and as far as I understand, it has something to do with running an LXC on ZFS. After spending about 3 hours I gave up and did a manual installation.


For a current installation guide, have look on their website here.
Install https support for apt and add Collabora CODE repository. (CODE = Collabora Online Development Edition)

sudo apt install apt-transport-https ca-certificates
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 0C54D189F4BA284D

Add the Collabora CODE repository to the apt sources list.

nano /etc/apt/sources.list.d/collabora.list

Add the following line for Debian Buster:

deb https://www.collaboraoffice.com/repos/CollaboraOnline/CODE-debian10 ./

Now update the repository and install Collabora. (lool = LibreOffice OnLine)

sudo apt update
sudo apt install loolwsd code-brand


You have to edit three sections in the config: SSL handling, inserting your Nextcloud domain as WOPI client and add some credentials for webinterface. So open the config with:

nano /etc/loolwsd/loolwsd.xml
  1. If you are using a reverse proxy (I have running a docker with nginx) which is managing all SSL certifactes, you don’t need local certifactes for your Collaboraoffice. So scroll down to the SSL settings, disable SSL and enable SSL termination.
   <ssl desc="SSL settings">
        <enable type="bool" desc="Controls whether SSL encryption is enable (do not disable for production deployment). If default is false, must first be compiled with SSL support to enable." default="true">false</enable>
        <termination desc="Connection via proxy where loolwsd acts as working via https, but actually uses https." type="bool" default="true">true</termination>
  • 2. Next add you Nextcloud domain in the WOPI storage section.
    <storage desc="Backend storage">
        <filesystem allow="false" />
        <wopi desc="Allow/deny wopi storage. Mutually exclusive with webdav." allow="true">
            <host desc="Regex pattern of hostname to allow or deny." allow="true">localhost</host>
            <host desc="Regex pattern of hostname to allow or deny." allow="true">nextcloud\.domain\.org</host>
  • 3. Add your credentials fot the webinterface.
  <admin_console desc="Web admin console settings.">
        <enable desc="Enable the admin console functionality" type="bool" default="true">true</enable>
        <enable_pam desc="Enable admin user authentication with PAM" type="bool" default="false">false</enable_pam>
        <username desc="The username of the admin console. Ignored if PAM is enabled.">user_name</username>
        <password desc="The password of the admin console. Deprecated on most platforms. Instead, use PAM or loolconfig to set up a secure password.">super_secret_password</password>

Now restart loolwsd and check the status.

systemctl restart loolwsd.service
systemctl status loolwsd.service

Check if the https connection is working via browser https://ipaddress:9980 or curl:

curl -vkI https://localhost:9980

You can reach the webinterface with:


Reverse Proxy

Go to your reverse proxy, in my case it’s nginx proxy manager, and add another subdomain for collabora with an SSL certificate.

You also have to add a few custom locations. Look at the Collabora website for the some nginx configs. I used the second with “SSL terminates at the proxy”. I also added the given custom locations via the webui, e.g.:

You should now be able to reach Collabora through your new subdomain via https.
And if you added /lool/adminws in your nginx config, you can also access the webui.

Install & configure Collabora Online App in Nextcloud

The easiest part is to install the Collabora Online App.
If done, go to Settings -> Collabora Online and set your Collabora Domain https://collabora.your.domain.org/ in here. Apply and edit your first excel in Nextcloud.

Done! 🙂

[ZFS] Rollback LXC

Look for a specific snapshot of your LXC.

sudo zfs list -rt snapshot | grep data/lxc/subvol-101

I just want to rollback 2 hours, so I choose the snapshot with timestamp 2019-12-05-1117.

data/lxc/subvol-110-disk-0@zfs-auto-snap_hourly-2019-12-05-0917   11,7M      -     24,2G  -
data/lxc/subvol-110-disk-0@zfs-auto-snap_hourly-2019-12-05-1017   11,9M      -     24,2G  -
data/lxc/subvol-110-disk-0@zfs-auto-snap_hourly-2019-12-05-1117   11,7M      -     24,2G  -
data/lxc/subvol-110-disk-0@zfs-auto-snap_hourly-2019-12-05-1217   11,8M      -     24,2G  -
data/lxc/subvol-110-disk-0@zfs-auto-snap_hourly-2019-12-05-1317   12,1M      -     24,2G  -

If there are one or more snapshots between the current state and the snapshot you want to rollback to, you have to add -r (force deletion) to the rollback command.

sudo zfs rollback -r data/lxc/subvol-110-disk-0@zfs-auto-snap_hourly-2019-12-05-1117

[ABAP] Fill table rows into range table

DATA(pernrs) = VALUE pernr_tab( ( |00000001| )
                                ( |00000002| )
                                ( |00000003| ) ).

DATA(lr_pernr) = VALUE cchry_pernr_range( FOR pernr IN pernrs ( sign   = 'I'
                                                                option = 'EQ'
                                                                low    = pernr
                                                                high   = '' ) ).
"Append row to range

APPEND VALUE #( option = 'EQ'
                sign   = 'I'
                low    = pernr ) TO lr_pernr.