Around 2000-2010, shared hosting was extremely popular as a cheap solution (sometimes a few $ / month, or sometimes even free for just a few MB) for people starting blogs, small websites, e.g. using Wordpress.

There was usually:

* just Apache + PHP + MySQL
* no SSH, only (s)FTP access
* something like 100 MB
* as far as I remember, they probably didn't create a new virtual machine for each account

**Question: before containerization / Docker went popular, how did major shared hosting providers ensure user isolation?**

Did they just used `ChrootDirectory` in sshd\_config + different users like in [How to create an isolated/jailed SFTP user?](https://unix.stackexchange.com/questions/561290/how-to-create-an-isolated-jailed-sftp-user/561350#561350) + `<VirtualHost>` config with `open_basedir` to prevent PHP code to access other accounts' files?

More generally, what were the main isolation techniques, preventing `user1234` to access `user5678`'s files on the same server with some malicious PHP code?