LXD

How to Limit Resources on a LXD Container?

LXD containers are lightweight virtual machines that provide isolated environments for applications to run. While they are designed to be lightweight and resource-efficient, it is still possible for applications to consume excessive resources and affect the overall performance of the system. To ensure that the resources of your LXD containers are used efficiently, it is…

security.txt

Implementing security.txt.

A new standard has been proposed that will allow Web sites to provide a way to communicate security-related issues. A “security.txt” file containing the relevant information should be placed in the “.well-known” directory of the web server. The securitytxt.org website has a form that allows you to quickly generate the text to be included in…

BTRFS

Adding BTRFS storage pool to LXD with an existing loop device.

In a previous post, we looked at creating a BTRFS loop device. In this tutorial, we are going to add an existing BTRFS storage pool to LXD. # storage create new-btrfs btrfs source=/mnt/btrfs Check the configuration # lxc storage show new-btrfs config: source: /mnt/btrfs volatile.initial_source: /mnt/btrfs description: “” name: new-btrfs driver: btrfs used_by: [] status:…

acme.sh

Remove domain from list of certificates in acme.sh.

It often happens that a domain is moved to another web server or is simply no longer registered and the corresponding certificate needs to be removed from the list of domains that acme.sh maintains. This can be done easily with the following command: # acme.sh –remove -d my_domain.com [Wed Feb  1 15:10:58 CEST 2022] my_domain.com…

Ubuntu 22.04 | ERPnext

Installing ERPNext 14 on Ubuntu 22.04

ERPNext is a promising Open Source ERP solutions that, unlike similar products such as Odoo is completely Open Source and as such does not require paying modules to use all its functionalities. ERPNext is built on the Frappé Framework that can be managed with the cli tool “bench”. Although somewhat cumbersome, installation is not really…

Postfix

Whitelist Hosts or IP addresses in Postfix.

To prevent a mail server in your own network (e.g. for sending alerts) from being blocked by the mail scanners/filters on your main Postfix mail server it is best to whitelist it Create a new file “rbl_override”. #vi /etc/postfix/rbl_override Add the IP addresses and host names you want to whitelist. 1.2.3.4 OK 1.2.3.5 OK [2a02:c123:1234:5a78::1]…

Letsencrypt | Certbot

Adding domains to existing Letsencrypt certificate using Certbot.

If you want to add one or more (sub)domains to an existing Letsencrypt certificate, you can use Certbot with the “–cert-name” option to accomplish this. # certbot certonly –cert-name existing-domain.com –webroot -w /var/www/virtual/existing-domain.com/htdocs/ -d existing-domain.com -d www.existing-domain.com -d first-new-domain.com -d www.first-new-domain.com -d second-new-domain.net -d www.second-new-domain.net -d third-new-domain.org -d www.third-new-domain.org Make sure you have added all…

LXD | ZFS

Fix “dataset is busy” error when deleting container in LXD.

If you try to delete a LXD container, you may get a “dataset is busy” error message because the dataset the container uses in the ZFS storage pool remains mounted in the namespace used by LXD. In this example, we will simulate this problem by trying to delete a container “alpine”. # lxc delete alpine…