Can I use one Apache Solr installation for multiple Drupal sites?

Question

Drupal

Good afternoon, please help, there is a virtual machine on Windows on which Java and Apache Solr are installed.
There are about 3-5 Drupal sites, one of which uses the Search API and the Solr Search API.
Everything is set up, the configuration scheme is taken specifically for Drupal, everything seems to be fine!
And now other sites need to use the power of the search engine too, the question is ...
can one engine be used for several sites, i.e. Let's say we do some kind of
index split for each site?

Answer 1

You need to use Solr in multicore mode. There is even an example in the solra folder: the multicore folder. Each core will have its own URL in the Search API settings.
There are many examples on the internet depending on your OS and JAVA webserver.
https://www.drupal.org/node/484800
https://coderwall.com/p/0s3flw

Answer 2

It is necessary to make several indexes on the same Solra server. Each site has its own index. happy end.