Did you cringe? did you click on it because you were curious? do you know what Azure is?

What if we call it Azure AD? NOW, I hope I have your interest....

AD, as some of you know, is geek for Active Directory, which is geek for the windows version of domain management. Azure AD, take it a couple steps further. 

Many of you are familiar with Active Directory, If your organization has a domain (not just a domain name) you probably use AD every day. Basically the AD is the central domain database for your domain. It keeps track of users and their permissions to your resources, It stores and enforces security and other policies, and does many other things that we will not talk about in this document. 

Traditionally, an organization has a network administrator (or a managed services SLA with an IT company) that manages your domain. While the AD itself is not to much of an administrative burden, all the resources that it consumes are burdensome, and expensive.

Lets say you have a SQL database or two, or a hundred, Lets say you have an on-premises Exchange server. Maybe you have some virtual machines. Active Directory is responsible for management of these resources. 

AD was quite the revolution back in 2000, It replaced the old schema of NT and LDAP. While LDAP is still the first line standard in the majority of very large systems,  windows systems play much better with AD than with standard LDAP so, a typical Network from 5 to 10000000 users utilizing primarily windows systems and services probably uses AD

I digressed......

In the old days, you had a server (Domain controller) sitting in the back room. It  whirred away day in, day out logging users onto your domain, protecting your data, enforcing domain policies, collecting dust, and turning expensive electricity into fan noise.  These had to be fairly robust pieces of hardware they were expensive, they required maintenance, both physical and administrative. A domain controller could survive almost indefinitely. if it was regularly updated (software) regularly cleaned (hardware) and regularly fed with new and larger storage systems behind it (Expensive hardware) Inevitably however, a domain controller would have a bad day, perhaps it had a serious hardware failure, or was attacked by a virus, or just ran out of storage.  If you were lucky, you had a properly managed Backup Domain Controller (BDC) that would take over the duties of the Primary Domain Controller (PDC) until it was feeling better. If you were not so lucky, or had not made enough of an initial capital investment, or cut your IT budget to the bone during hard times,  you and all your users were out of business until it was fixed. You business stopped.