Compare DirectAdmin and Plesk

wikipedia.org:
https://en.wikipedia.org/wiki/Comparison_of_operating_systems
https://en.wikipedia.org/wiki/Comparison_of_Linux_distributions
https://en.wikipedia.org/wiki/Comparison_of_web_hosting_control_panels
(information about OpenSSL 1.1 with TLS 1.3 is behind)

DirectAdmin Control Panel:

rewriting to HTTPS can be set up within the control panel
forced rewriting to the www subdomain or without www can be chosen
(design failure: rewriting needs change to 301 /302 redirecting after any security header in .htaccess and / or on httpd / web server level, because the first HTTPS is used)
four PHP versions to choose from
storage of SSL certificate in one place: no, several folders; use symlinks
change DNS for all domains: no
nice control of changed settings in php.ini: no
reseller functionality: included in basic costs
update of components: manually with plugin CustomBuild
firewall: with e.g. plugin CSF
fight spam: set up SpamAssassin
TLSA in DNS as name server: yes rekeying’
no rekeying of Let’s Encrypt to guarantee TLSA 311 setup: no
CAA in DNS as name server: yes
install WordPress easily: not automated
update a database connection generally: no
SSL Labs score for our VPS host (Apache): optimal with A+
ODBC: working
plugin CustomBuild supports PHP 7.3 as default
a change in httpd (deamon) can be reloaded (connections do not get lost)
Docker containers are not included in the menu; I have no proper information
searching the menu works intuitive

Plesk Control Panel:

rewriting to HTTPS can be set up within the control panel
forced redirecting to the www subdomain or without www can be chosen
unlimited number of PHP versions; phased out is mentioned
storage of SSL certificate in one place: yes
change DNS for more domains: yes
nice control of changed settings in php.ini: yes
reseller functionality: not included in basic costs
update of components: automatically by Plesk
firewall: by Plesk itself
fight spam: set up SpamAssassin
TLSA in DNS as name server: no; Postfix does work with TLSA
no rekeying of Let’s Encrypt to guarantee TLSA 311 setup: no
CAA in DNS as name server: yes
install WordPress easily: yes
update a database connection generally: yes
SSL Labs score for our VPS host (Apache/Nginx): optimal with A+
ODBC: MySQL driver probably needs additional local components;
I could install PHP 7.3 from the command line
a change in httpd (deamon) immediately restarts (connections get lost)
menu is ready for Docker containers
searching the menu requires explanation

Note: Differences depend on personal use. Please send me email in order to improve.

About alternatives to control panel cPanel (that gets pricey):

https://www.websiteplanet.com/blog/best-cpanel-alternatives/

OpenStack can manage instances (NASA re-embraces this open source):

https://www.openstack.org/
https://en.wikipedia.org/wiki/OpenStack
nl: http://www.openstack.nl/wat-is-openstack/
in NL: for OpenStack see eg https://cloudvps.com
(CloudVPS B.V. (of IT-Ernity Holding B.V.) is part of TransIP Group B.V. since 2018)

Docker containers (Docker declared this open-source production-ready):

https://www.docker.com/
https://en.wikipedia.org/wiki/Docker_(software)
https://en.wikipedia.org/wiki/Docker,_Inc.
For Development, Testing, Acceptance and Production environments (DTAP) in DevOps teams:
Website containers that work, can easily be moved from one platform to another, even for a part of the application, and for heavy use. In this way, updates and upgrades of all kinds of components are no longer destabilizing the production environment.

Containerization is about running applications such that the application is isolated. Even on a VPS, which is already virtualized, (clusters of) containers can work, each with their prerequisite software.

In fact, a Docker container is a namespace under the same kernel in the old POSIX philosophy, such as the long-standing LXC (Linux Containers) https://en.wikipedia.org/wiki/POSIX / https://en.wikipedia.org/wiki/LXC).

Google open-sourced Kubernetes, that can take responsibility for launching and managing Docker containers. In OpenStack stacks can be created to launch and manage in a technically advanced way. Use explanation such as https://www.techrepublic.com/videos/a-better-way-to-install-docker-on-centos-8/.

See also Red Hat operating system and control panel for containers:
Container Linux (formerly CoreOS Linux): https://en.wikipedia.org/wiki/Container_Linux
OpenShift (Tectonic is to be, or is, integrated): https://en.wikipedia.org/wiki/OpenShift