1 00:00:00,000 --> 00:00:00,833 ‫The first service 2 00:00:00,833 --> 00:00:02,370 ‫that is going to be very important for 3 00:00:02,370 --> 00:00:06,770 ‫us to deploy a global application is Amazon Route 53. 4 00:00:06,770 --> 00:00:10,690 ‫So, Route 53 is a managed DNS or Domain Name System. 5 00:00:10,690 --> 00:00:11,930 ‫And what does the DNS? 6 00:00:11,930 --> 00:00:13,710 ‫Well, DNS is just like a phone book. 7 00:00:13,710 --> 00:00:15,720 ‫It's a collection of rules and records, 8 00:00:15,720 --> 00:00:19,081 ‫which help clients find the right servers through URLs. 9 00:00:19,081 --> 00:00:22,760 ‫So let's go through the most common records in AWS. 10 00:00:22,760 --> 00:00:23,593 ‫For example, 11 00:00:23,593 --> 00:00:27,677 ‫say you are mapping www.google.com to an IPv4 address. 12 00:00:29,121 --> 00:00:31,547 ‫Then this is called an A record. 13 00:00:31,547 --> 00:00:36,547 ‫If you are mapping www.google.com to a long IPv6 address, 14 00:00:36,980 --> 00:00:39,669 ‫it's called the quadruple A record. 15 00:00:39,669 --> 00:00:43,150 ‫Also, if you map a host name to another host name, 16 00:00:43,150 --> 00:00:46,160 ‫so search the www.google.com come into the previous address. 17 00:00:46,160 --> 00:00:47,550 ‫It's called a CNAME because we're 18 00:00:47,550 --> 00:00:49,430 ‫mapping a host name to host name. 19 00:00:49,430 --> 00:00:50,300 ‫And then finally, 20 00:00:50,300 --> 00:00:53,660 ‫if you're mapping a host name into an AWS resource, 21 00:00:53,660 --> 00:00:56,720 ‫it's a special type of record called an Alias record. 22 00:00:56,720 --> 00:00:59,240 ‫And that works for you if you have an ELB, 23 00:00:59,240 --> 00:01:01,230 ‫or if using CloudFronts, S3, 24 00:01:01,230 --> 00:01:03,670 ‫an RDS database, et cetera, et cetera. 25 00:01:03,670 --> 00:01:04,700 ‫Now, going into the exam, 26 00:01:04,700 --> 00:01:07,010 ‫you don't need to know all the types of records, 27 00:01:07,010 --> 00:01:08,350 ‫but I just wanted to give you an overview of 28 00:01:08,350 --> 00:01:10,300 ‫them in this lecture. 29 00:01:10,300 --> 00:01:11,910 ‫So, from an Exam perspective, 30 00:01:11,910 --> 00:01:14,180 ‫Route 53 is a managed DNS, 31 00:01:14,180 --> 00:01:16,200 ‫but let's go one step further because you need to 32 00:01:16,200 --> 00:01:18,430 ‫understand a little bit better how it works. 33 00:01:18,430 --> 00:01:19,410 ‫So for example, 34 00:01:19,410 --> 00:01:20,870 ‫for Route 53 say, 35 00:01:20,870 --> 00:01:23,670 ‫we want to see what happens for an A Record. 36 00:01:23,670 --> 00:01:25,140 ‫So our Web browser is here. 37 00:01:25,140 --> 00:01:25,973 ‫That's a Web browser, 38 00:01:25,973 --> 00:01:28,590 ‫and we have an Application Server that we've deployed that 39 00:01:28,590 --> 00:01:30,260 ‫has a public IPv4. 40 00:01:30,260 --> 00:01:32,820 ‫Now we want to be able to access our application server 41 00:01:32,820 --> 00:01:34,660 ‫using a normal URL. 42 00:01:34,660 --> 00:01:37,260 ‫So for this, we're going to go into Route 53 and 43 00:01:37,260 --> 00:01:39,940 ‫we're going to create a, A Record. 44 00:01:39,940 --> 00:01:41,860 ‫And so that when the Web browser does 45 00:01:41,860 --> 00:01:45,376 ‫a DNS Request for myapp.mydomain.com 46 00:01:45,376 --> 00:01:49,370 ‫then the DNS will reply back with an IP. 47 00:01:49,370 --> 00:01:53,410 ‫And then that IP can be used by our Web browser to 48 00:01:53,410 --> 00:01:55,640 ‫get to our correct server. 49 00:01:55,640 --> 00:01:58,950 ‫and then get the HTTP Response from our server. 50 00:01:58,950 --> 00:02:01,330 ‫And this is the basics of how a DNS work at 51 00:02:01,330 --> 00:02:02,730 ‫a very, very high level. 52 00:02:02,730 --> 00:02:05,900 ‫What you need to understand as well for Route 53, 53 00:02:05,900 --> 00:02:08,860 ‫from an Exam perspective is the Routing Policies. 54 00:02:08,860 --> 00:02:11,000 ‫So, we need to know them at a high-level and decide what's 55 00:02:11,000 --> 00:02:12,350 ‫the right one based on the use case, 56 00:02:12,350 --> 00:02:14,100 ‫because you'll see, it's pretty simple. 57 00:02:14,100 --> 00:02:16,790 ‫So, the first one is called a Simple Routing Policy, 58 00:02:16,790 --> 00:02:18,260 ‫which has No health checks. 59 00:02:18,260 --> 00:02:21,070 ‫So our Web browser will go into our DNS system, 60 00:02:21,070 --> 00:02:25,340 ‫does a DNS query and gets an IPv4 for example as a result, 61 00:02:25,340 --> 00:02:27,240 ‫that's a Simple Routing Policy. 62 00:02:27,240 --> 00:02:29,040 ‫The basic one, we can understand. 63 00:02:29,040 --> 00:02:30,373 ‫The Weighted Routing Policy, 64 00:02:30,373 --> 00:02:33,880 ‫allows us to distribute the traffic across 65 00:02:33,880 --> 00:02:35,770 ‫multiple Institute instances. 66 00:02:35,770 --> 00:02:36,603 ‫So in this example, 67 00:02:36,603 --> 00:02:39,493 ‫we have to assign weights to our Institute instances, 68 00:02:39,493 --> 00:02:41,860 ‫for example, 70, 20, and 10, 69 00:02:41,860 --> 00:02:45,200 ‫and then our DNS we'll make sure that our clients have 70 00:02:45,200 --> 00:02:47,520 ‫70% of the traffic onto the first one, 71 00:02:47,520 --> 00:02:49,437 ‫20% of the traffic onto the second one and 72 00:02:49,437 --> 00:02:52,450 ‫10% of the traffic on to the third one. 73 00:02:52,450 --> 00:02:55,540 ‫This is effectively some kind of load balancing. 74 00:02:55,540 --> 00:02:57,670 ‫So in this Weighted Routing Policy, 75 00:02:57,670 --> 00:02:59,580 ‫we can use health checks. 76 00:02:59,580 --> 00:03:02,600 ‫Next, we have the Latency Routing Policy. 77 00:03:02,600 --> 00:03:03,433 ‫So in this example, 78 00:03:03,433 --> 00:03:06,070 ‫we'll say we are displaying our application globally, 79 00:03:06,070 --> 00:03:07,530 ‫one in California, 80 00:03:07,530 --> 00:03:09,370 ‫and the other one in Australia. 81 00:03:09,370 --> 00:03:11,660 ‫And our users are all around the world. 82 00:03:11,660 --> 00:03:14,450 ‫The Latency Routing Policy we'll look at where 83 00:03:14,450 --> 00:03:16,010 ‫the user is located. 84 00:03:16,010 --> 00:03:18,300 ‫And if they're located close to 85 00:03:18,300 --> 00:03:20,450 ‫our Kelly American Institute instance, 86 00:03:20,450 --> 00:03:23,970 ‫then they will be redirected to talk to that server. 87 00:03:23,970 --> 00:03:25,470 ‫And if they're close to Australia, 88 00:03:25,470 --> 00:03:26,540 ‫then they will be redirected to 89 00:03:26,540 --> 00:03:27,980 ‫talk to the Australia server. 90 00:03:27,980 --> 00:03:29,970 ‫And this is based on the latency. 91 00:03:29,970 --> 00:03:31,200 ‫So, in this example, 92 00:03:31,200 --> 00:03:34,850 ‫Route 53 will be used to minimize the latency between the 93 00:03:34,850 --> 00:03:36,660 ‫users and the servers by making the 94 00:03:36,660 --> 00:03:38,310 ‫users connect to the server. 95 00:03:38,310 --> 00:03:40,700 ‫That is the closest to them. 96 00:03:40,700 --> 00:03:41,550 ‫And then finally, 97 00:03:41,550 --> 00:03:44,180 ‫we have a Failover Routing Policy in which 98 00:03:44,180 --> 00:03:46,040 ‫we have a client and we have 99 00:03:46,040 --> 00:03:48,627 ‫a primary institute instance and a Failover one. 100 00:03:48,627 --> 00:03:53,090 ‫And so our DNS system will do a Health check On the primary. 101 00:03:53,090 --> 00:03:55,560 ‫And in case the primary instance fails, 102 00:03:55,560 --> 00:03:57,770 ‫then we will be redirected to the failovers. 103 00:03:57,770 --> 00:03:59,480 ‫This helps with disaster recovery. 104 00:03:59,480 --> 00:04:03,060 ‫So the clients will know exactly thanks to Route 53, 105 00:04:03,060 --> 00:04:05,170 ‫which instance to connect to based on the 106 00:04:05,170 --> 00:04:06,700 ‫health of that instance. 107 00:04:06,700 --> 00:04:07,533 ‫So that's it, 108 00:04:07,533 --> 00:04:09,450 ‫that's our the four Routing Policies you need to know. 109 00:04:09,450 --> 00:04:11,200 ‫Just a first one does not have a Health check. 110 00:04:11,200 --> 00:04:13,300 ‫All the other ones have Health checks and they 111 00:04:13,300 --> 00:04:15,030 ‫all serve different purposes. 112 00:04:15,030 --> 00:04:17,670 ‫So, Weighted Routing Policy is to distribute the 113 00:04:17,670 --> 00:04:19,900 ‫traffic across multiple institute instances. 114 00:04:19,900 --> 00:04:21,486 ‫Latency is to minimize latency and 115 00:04:21,486 --> 00:04:24,695 ‫Failover is to help with Disaster Recovery. 116 00:04:24,695 --> 00:04:26,200 ‫So hope that was helpful. 117 00:04:26,200 --> 00:04:28,150 ‫And I will see you in the next lecture.