IcingaWeb2 Installation on Ubuntu 20.04.03 Server doesnt work

Hello there, i try to install IcingaWeb2 on my Virtual Machine.
I have made the tutorial listed below, but without the clustering. I have only one icinga vm and one icingaweb and database vm.
I have changed the php versions in …
“apt install -y apache2 ssl-cert php7.2 libapache2-mod-php7.2 php7.2-xml php7.2-opcache php7.2-xml php7.2-mbstring php7.2-json php7.2-curl php7.2-ldap php7.2-cli php7.2-gd php7.2-intl php7.2-readline php7.2-pgsql”
… to PHP7.4

What’s not working about IcingaWeb2? Webserver error? PHP error? DB error?

Oh, I am sorry. I forgot to include the error message.
This appears when I go to the Icinga2 web server:

Fatal error : Uncaught ErrorException: Uncaught ErrorException: include(): \Icinga\Web\ViewStream::stream_set_option is not implemented! in /usr/share/php/Icinga/Web/View.php:262 Stack trace: #0 /usr/share/php/Icinga/Web/View.php(262): Icinga\Application\ApplicationBootstrap->Icinga\Application{closure}() #1 /usr/share/php/Icinga/Web/View.php(262): include() #2 /usr/share/icingaweb2/library/vendor/Zend/View/Abstract.php(877): Icinga\Web\View->_run() #3 /usr/share/icingaweb2/library/vendor/Zend/Controller/Action/Helper/ViewRenderer.php(904): Zend_View_Abstract->render() #4 /usr/share/icingaweb2/library/vendor/Zend/Controller/Action/Helper/ViewRenderer.php(925): Zend_Controller_Action_Helper_ViewRenderer->renderScript() #5 /usr/share/icingaweb2/library/vendor/Zend/Controller/Action/Helper/ViewRenderer.php(964): Zend_Controller_Action_Helper_ViewRenderer->render() #6 /usr/share/icingaweb2/library/vendor/Zend/Controller/Action/HelperBroker.php(272): Zend_Controller_Action_Helper_ViewRenderer->postDispatch() #7 /usr/share/icin in /usr/share/icingaweb2/library/vendor/Zend/Controller/Plugin/Broker.php on line 259

Does any landing page show up at all?

Did you install ipl and other libraries noted in the installation docs?

IPL and Thirdparty are often forgotten about.

The only thing thats coming is this:

I only followed the tutorial I mentioned, because the official documentation is too complicated for me.
How can I install these packages?

This error occurs in case the Icinga Web 2 version isn’t compatible with the PHP version used.

Make sure to run the latest Icinga Web 2 version.

How can I do this? I’ve tiped in these commands to install IcingaWeb2:
apt install -y icingaweb2 icingacli icingaweb2-module-monitoring

I suspect you’ve installed not the packages of the Icinga repository, but from debian/ubuntu upstream. (The tutorial you’ve linked doesn’t include a call to apt update)

Run apt update first, and then apt install icingaweb2 icingacli.

Though, generally, I’d advice you to also read the official installation documentation. It may clear some things up which the tutorial is missing. Or vice versa, but at least only the tutorial isn’t sufficient.

Alright thank you!
Should I do apt-update before installing php or just before installing icingaweb2?
I have made an apt-update and upgrade before starting with part 1 of the tutorial.

I have made an apt update before installing icinagaweb2, but there were no new packages to upgrade.