Now let's take a look at your public load balancer. Again, what public load balancer means is that it's going to come with an IP address for your load balancer, an IP address that is public and reachable from the Internet. It's going to be accepting traffic from the Internet according to the rules that you have in place on your route table and according to the policies that you have on your security list. For redundancy, a public load balancer requires either original subnet or to availability domain-specific subnets. Either one of those, you can still work with your load balancer. When you create a load balancer, you'll only see the primary load balancer, but it's redundant by nature. If your load balancer goes down, there's a secondary that you don't see, that you don't have access to it that is ready and available for it to take action in case the first one goes down, so it's transparent to you. You don't know, but it's high availability load balancer. In the case where you have the subnets specific load balancer, the configuration will create the second load balancer in another availability domain to make sure that if in case the availability domain goes down, then the second load balancer, the one that is in standby, will be in a different availability domain, so it won't be affected by one of AD going down. They'll get a floating public IP and it's going to be attached to the primary load balancer. In case it goes down, that floating IP is floating, so it goes to the secondary load balancer. The load balancing service treats the two load balancers as equivalent and you cannot select which one is primary and which one is secondary. You just create a load balancer and by default it comes with a second load balancer. This is how it looks like when you have a regional subnet, the VCN is covering both availability domains and also the subnet. It's a regional subnet, so you have even those regional, the second load balancer, we're going to call it the second load balancer for the failover is on a separate availability domain. Now they reach their back-end servers through the back-end set. It's no different actually from the availability specific subnet, it's no different in the way that they're both, in this case they're in their own subnet and the subnet is tied to the availability domain, but the second load balancer was created on the second availability domain for your second subnet. Then they reach your back-end service. Now let's go ahead and take a look at the private load balancer and how it behaves. It's exactly the same, but let me go back to this slide and you will see that here, I didn't point it out earlier, but you can see clearly a router icon and that router icon, it's the Internet gateway and is providing you access to the Internet gateway. When we go and see the private load balancer, you will see that it's private, it doesn't come with a public IP address, but the configuration is exactly the same as the public load balancer, as you can see in the following slide. The client can access your private load balancer only from within the Oracle Cloud Infrastructure Service or from if you are leveraging a dynamic routing gateway so you can connect to on-premises via on-premises as well, or from another region through the remote prem connection. This is the private load balancer when you're using the regional subnet. As you can see, there's no router, there's no Internet gateway icon right there. But the configuration is exactly the same. You have one active load balancer in one availability domain, and you have a standby or failover load balancer in another availability domain in this original subnet, and then they go to the back-end servers. When you have availability domain specific subnets, the second load balancer will be created in a different availability domain. Then you go in and you have the connections to your back-end set. Let's talk about the back-end sets and those connections. As you can see, the active load balancer has active connections to the back-end set in all four notes of them. The failover load balancer has standby connections, so in case the load balancer on availability domain 1 goes down, then those dotted lines will become red, meaning that they will be the ones that are active going forward. Let's go ahead and move on to the next section.
