I think you mixed up 2 things:
ido => old deprecated way icinga2 stores data
ido uses the icingaweb2 module “monitoring”
icingadb uses the icingaweb2 module icingadb-web, which is than named icingadb once installed
You can read this in combination with the docs:
I do not point out this post because the user had a problem, but his problem was only 32bit related, but his installation instructions are pretty straight forward.