1 00:00:04,700 --> 00:00:09,410 Let me know, explain to you how different containers communicate with each other when you bring them 2 00:00:09,410 --> 00:00:16,070 up using Docker compose instead of the Docker Compose creates new breach network. 3 00:00:16,370 --> 00:00:22,670 And we've seen logs about that region network is assigned specific range of IP addresses. 4 00:00:23,300 --> 00:00:32,000 For example, you might see such range 172 22 zero zero 16 16 is Network Maersk for this particular 5 00:00:32,000 --> 00:00:32,479 network. 6 00:00:33,140 --> 00:00:40,310 And each container that is included in the Docker compose file gets unique IP address from this range. 7 00:00:41,000 --> 00:00:46,420 For example, on my computer, containers were assigned sadjapour addresses front and container. 8 00:00:46,700 --> 00:00:50,700 Such payload was API container or got such a payload was Mongo. 9 00:00:50,750 --> 00:00:53,780 This one and Mongo expressed this one again. 10 00:00:53,780 --> 00:00:57,620 Those IP addresses are different, but they belong to the same network. 11 00:00:57,890 --> 00:01:05,180 This network, in this example also there was default gateway for each container and usually default 12 00:01:05,180 --> 00:01:05,720 gateways. 13 00:01:05,720 --> 00:01:12,470 A third was ants with one in the last octet, and it is first usable IP address in this network. 14 00:01:13,160 --> 00:01:19,760 Also, there was port mapping for several containers in Docker compose configuration file and there 15 00:01:19,760 --> 00:01:26,150 was port three thousand exposed by front and container, and it is exposed to the same port three thousand 16 00:01:26,150 --> 00:01:29,000 on the local computer where you are run Docker. 17 00:01:29,940 --> 00:01:36,240 50 50 brought is brought exposed by API container, and it is exported the same brought on local computer 18 00:01:36,240 --> 00:01:40,320 5:50pm and Mongo Express container also has exports. 19 00:01:40,320 --> 00:01:49,050 Port 80, a dual Mongo container, does not have any exposed ports, but it does not stop all the containers 20 00:01:49,290 --> 00:01:55,860 from communication with Mongo container due to the fact that all those containers internally inside 21 00:01:55,860 --> 00:02:03,120 it was a Docker belong to the same network and they could communicate with each other using their IP 22 00:02:03,120 --> 00:02:03,750 addresses. 23 00:02:04,410 --> 00:02:07,920 Other than that, instead of the Docker, there was also a DNS server. 24 00:02:08,430 --> 00:02:15,270 And instead of that DNS server, Docker creates corresponding DNS mappings for the names of the services 25 00:02:15,270 --> 00:02:21,410 defined inside of the Docker compose file to corresponding IP addresses assigned to the containers. 26 00:02:22,560 --> 00:02:30,060 And this means that, for example, front and container might reach one container, either by its name 27 00:02:30,060 --> 00:02:35,370 Mongo, that will be the result of this eBay address or directly knowing the CPRS. 28 00:02:36,330 --> 00:02:42,090 But IP addresses might be assigned differently each moment when you start Docker compose. 29 00:02:42,780 --> 00:02:49,020 But those services names front and API Munguia and Montebourg Express remain unchanged. 30 00:02:49,470 --> 00:02:55,470 This way, if you want to communicate between containers internally in this network, you could simply 31 00:02:55,470 --> 00:02:59,010 utilize services names, for example Mongo or API. 32 00:02:59,490 --> 00:03:02,700 That's what we do instead of the Mongo Express container. 33 00:03:03,090 --> 00:03:07,590 We define that there are server name of the Mongo server simply as Mongo. 34 00:03:08,250 --> 00:03:12,690 And this name will be resolved internally by internal DNS servers of the Docker. 35 00:03:13,020 --> 00:03:14,970 To this, a build was in my example. 36 00:03:15,480 --> 00:03:21,090 Also note is that on your computer or such network for all those containers might be different from 37 00:03:21,090 --> 00:03:25,260 mine, but usually range starts with one hundred seventy two. 38 00:03:25,560 --> 00:03:30,390 And those IP addresses from those ranges are considered as private data addresses. 39 00:03:30,630 --> 00:03:36,720 They are not available in the global network internet, and there is no need to record them because 40 00:03:36,720 --> 00:03:42,270 actually between those containers inside it was a Docker and old site internet connection. 41 00:03:42,660 --> 00:03:47,100 There was network address translation that is also done by Docker internally. 42 00:03:47,880 --> 00:03:51,540 And this why each of the containers has access to internet. 43 00:03:51,630 --> 00:03:57,150 If your computer where you're running Docker has access to the internet, and that's why we were able 44 00:03:57,150 --> 00:04:03,330 to download, for example, npm packages in the front of the container or download Python packages inside 45 00:04:03,330 --> 00:04:04,590 of the API container. 46 00:04:05,160 --> 00:04:11,220 This network and works instead of a Docker when you bring up multiple services simultaneously using 47 00:04:11,220 --> 00:04:16,620 Docker compose and next up to the small balls of growth, let's examine that in practice. 48 00:04:16,980 --> 00:04:18,060 I'll see you just in a bit.