[MUSIC] In this chapter, you will learn about OCIs traffic steering management and health checks. Will be a collection of videos in which we will look at each component. So at a high level, there are two specific things we're going to talk about which is traffic management and health checks. This is available under networking. Under DNS management, we have the ability to do traffic steering. Where in just waiting. So you have the traffic steering policies here. And under monitoring, you have the ability to have health checks. Though these are located in two different menu options within OCI, they have an integration between them, which also we will explore. First, let's understand the idea behind using this services of traffic management and health checks. From the previous chapter where we discussed about load balancer, we know the load balancer is a regional service. So if I have a region and I will call it as region A, maybe Ashburn or Phoenix, and you have set up an application on various compute instances, which together can be grouped as a backend set. A collection of nodes with the same application, you can have a load balancer provisioned within that region, which will take care of high availability within the region. I'm just taking an example of a load balancer, but it is not necessary it has to be a load balancer. It could be a normal compute instance also. And the discussion I'm going to talk about right now is about public load balancer, but the same can be implemented from a private load balancer or a private resource. Now, when you have a public load balancer, you will of course have a public IP available with you and to be able to resolve this to a particular domain name in the DNS, you could have the resolution specified to the load balancer public IP. Again, as I told you, the context of the discussion here is with public IPs and public DNS, but the same can be implemented also in a private DNS. So if your application has a domain name registered, and you allow your end users to access it from the DNS, it would get routed to the IP associated with the load balancer. This is fair enough but let us say you want a highly available application not only within the region, but you have a need for a disaster recovery compliant environment. Or you may already have replicated your service that you have hosted inside your OCI region A to be replicated to other regions from number one or disaster compliance perspective. Or maybe you want to give people in specific geographic areas better response to the application. So you want to have them accessing the sources closest to them, which is the idea behind traffic steering by doing geolocation based steering and we will look at that a little later in detail. So when you want this to be replicated across multiple regions for example, you might set up compute instances in various regions of interest. You will have set up peering in the form of remote peering between regions, and replicate your application data between all the regions which you have set up for this application. So you may have all your data in sync. And you can have a load balancer set up for example, in every region. And the load balancer can have public IPs or private IPs as I discussed earlier, given the context of this discussion, considering public IPs available, you have the ability to use DNS based routing so that depending on, The environment. If you're doing a disaster recovery, as far as this is the primary site when it is available, your DNS will route it here. In case this site is unavailable, you want request to be routed to this, wherein we already know they're replicated. All this is possible with the ability to use traffic management. Or if you want people coming in from US to be redirected to this region, Europe to be redirected to this region, and let's say Asia Pacific to this region wherein you have subscribed to let's say a Mumbai, Frankfurt, and Ashburn. In doing so you are able to route traffic to a close region as far as the end user is concerned, which is also doable with traffic steering. This is a high level overview about this facility of traffic steering. We will look how we use it in other videos. And how will the DNS know whether the services available here or available here in case it has to do a load balancing or failover that is where health checks comes in. So both of them are complementing each other and we will see how we use these services within OCI. [SOUND]
