1 00:00:04,150 --> 00:00:11,680 We just verified that after Docker compose down up commands all data inside of the mongo container was 2 00:00:11,680 --> 00:00:12,370 lost. 3 00:00:12,550 --> 00:00:19,090 And the reason for that is that Docker Compose creates a brand new container each time when you enter 4 00:00:19,090 --> 00:00:21,790 Docker, compose down and up commands. 5 00:00:22,240 --> 00:00:30,820 And now let's add volumes mapping for mongo container in order to be able to persist MongoDB data and 6 00:00:30,820 --> 00:00:39,580 any container that is started using Mongo image will utilize the same volume and all MongoDB data therefore 7 00:00:39,580 --> 00:00:47,260 will be persistent and this volume will be created inside of the docker, not on your local computer. 8 00:00:47,590 --> 00:00:48,400 Why? 9 00:00:48,430 --> 00:00:55,450 Because actually we could perform volume mapping similarly as we did, for example, for API service. 10 00:00:55,690 --> 00:01:04,310 Here we mapped a folder that is located on your computer here to the app folder inside of the container. 11 00:01:05,340 --> 00:01:13,650 And actually container is now able not just to read data from the folder when it is running, but also 12 00:01:13,650 --> 00:01:17,970 it is able to write data to the folder if necessary. 13 00:01:18,000 --> 00:01:20,190 It is bidirectional communication. 14 00:01:20,550 --> 00:01:27,930 And actually we are able to now create, for example, here a new folder and name it, for example MongoDB 15 00:01:28,110 --> 00:01:36,300 and afterwards map this volume to the mongo container here using similar approach as we did here. 16 00:01:36,630 --> 00:01:44,730 But in such case, Mongo will actually write actual data to the MongoDB folder on your computer and 17 00:01:44,730 --> 00:01:50,760 it's not really convenient because this is images gallery project folder here you should store only 18 00:01:50,760 --> 00:01:55,030 project related files like JavaScript files, python files and so on. 19 00:01:55,050 --> 00:01:58,990 You should not store here some database information. 20 00:01:59,010 --> 00:02:06,550 That's why such approach is not convenient and in Docker it is possible to create volume inside of the 21 00:02:06,550 --> 00:02:13,990 Docker itself because what Docker is in a nutshell, it is just virtual machine on your macOS or Windows 22 00:02:13,990 --> 00:02:14,860 computer. 23 00:02:14,950 --> 00:02:22,540 And inside of that virtual machine it is possible to create volumes and map those volumes to the containers. 24 00:02:23,020 --> 00:02:30,250 And in such case, those volumes inside of the Docker will be persistent and they will be reusable by 25 00:02:30,250 --> 00:02:31,810 different containers. 26 00:02:31,990 --> 00:02:37,360 Notice that if you are running Linux like system and install Docker there, you actually run Docker 27 00:02:37,360 --> 00:02:43,600 Community Edition, not Docker Desktop and their volumes will be created directly on your computer. 28 00:02:43,600 --> 00:02:50,590 But for Windows and macOS users, Docker is just virtual machine and you could create volumes inside 29 00:02:50,590 --> 00:02:54,640 of that virtual machine and reuse them inside of the containers. 30 00:02:54,640 --> 00:02:57,340 And that's what we are about to do right now. 31 00:02:57,610 --> 00:03:04,720 Let's create new volume and for that you need to add instructions here at the root of the Yaml file 32 00:03:04,720 --> 00:03:07,840 and instruction is volumes like that. 33 00:03:07,930 --> 00:03:16,300 And here let's add new volume named for example MongoDB underscore data and make sure to add here colon 34 00:03:16,300 --> 00:03:19,720 afterwards with such syntax in place. 35 00:03:19,750 --> 00:03:27,040 Docker compose will create new volume called MongoDB underscore data inside of the Docker. 36 00:03:27,490 --> 00:03:35,740 And now we are able to use such volume and map it to containers and let's map it to mongo container 37 00:03:35,740 --> 00:03:36,310 here. 38 00:03:36,730 --> 00:03:41,530 And syntax is similar as we saw here volumes. 39 00:03:42,150 --> 00:03:43,170 Like that. 40 00:03:43,320 --> 00:03:46,260 And on the next line will be minus sign. 41 00:03:46,260 --> 00:03:53,370 And here are type simply name of the volume you want to map and it is MongoDB data. 42 00:03:53,610 --> 00:03:57,900 And note this suggestion from vs code MongoDB underscore data. 43 00:03:58,830 --> 00:04:05,400 And notice that there was no dot or forward slash here in front of the name of the volume, because 44 00:04:05,400 --> 00:04:12,720 in such way Docker will understand that you want to map internal Docker volume called MongoDB data volume 45 00:04:12,720 --> 00:04:14,280 that was created here. 46 00:04:15,210 --> 00:04:22,350 If you add here dot and forward slash, it will mean for Docker that you want to map volume on your 47 00:04:22,350 --> 00:04:28,590 local computer and it will try to find folder MongoDB underscore data in your project. 48 00:04:28,620 --> 00:04:34,890 Similarly, as it finds a folder or front end folder for corresponding containers. 49 00:04:35,160 --> 00:04:37,050 That's why you need to type here. 50 00:04:37,050 --> 00:04:39,670 Simply MongoDB underscore data. 51 00:04:39,690 --> 00:04:46,920 If you want to map volume from the Docker itself and here after colon, we need to specify destination 52 00:04:46,920 --> 00:04:54,420 folder inside of the mongo container and all data inside of the mongo is stored in following path. 53 00:04:54,450 --> 00:04:56,310 Data slash debe. 54 00:04:56,670 --> 00:05:03,540 It is default database path inside of the mongo server and that's actually it. 55 00:05:03,570 --> 00:05:06,810 Let's save changes and quickly summarize here. 56 00:05:06,810 --> 00:05:13,530 We created custom volume inside of the docker and this volume is called MongoDB Underscore data. 57 00:05:13,560 --> 00:05:17,050 You could give other name to this volume if you want to do so. 58 00:05:17,050 --> 00:05:20,910 And afterwards we map such custom volume. 59 00:05:20,920 --> 00:05:30,760 MongoDB underscore data to the data DB folder inside of the mongo container and in such case, any container 60 00:05:30,760 --> 00:05:37,810 that will be started by Docker compose will actually be connected to MongoDB, underscore data volume 61 00:05:37,810 --> 00:05:45,070 and any data that is created by one container inside of this volume will be reusable by other containers 62 00:05:45,070 --> 00:05:47,300 that are connected to the same volume. 63 00:05:47,320 --> 00:05:51,790 That's how we will persist data in the Mongo database. 64 00:05:51,880 --> 00:05:57,250 And now let's of course verify that on practice and let's proceed with that after the small pause.