WEBVTT 00:00.240 --> 00:03.400 In the last section, we finished up our persistent volume claim. 00:03.560 --> 00:06.960 I'm now going to flip over to my Postgres deployment file. 00:08.000 --> 00:10.240 So I'm going to find the template section of this. 00:10.280 --> 00:15.240 Remember this is the template that is used for every pod that is created by this deployment. 00:15.240 --> 00:17.960 And there's only ever going to be one pod at a time. 00:18.560 --> 00:23.520 We are going to update this template section and tell this pod that when it is created, it needs to 00:23.560 --> 00:26.720 request some type of long term storage. 00:26.720 --> 00:32.040 In other words, a persistent volume that meets all the requirements that were advertised by this persistent 00:32.040 --> 00:34.000 volume claim that we just put together. 00:34.800 --> 00:38.960 So inside of my Postgres deployment file, I'll find the template section. 00:38.960 --> 00:40.600 And then the spec inside there. 00:40.840 --> 00:44.480 And inside the spec we're going to add on a new key value pair. 00:44.920 --> 00:48.280 So I'm on the same indentation level as containers right here. 00:48.920 --> 00:51.040 And I'm going to say volumes. 00:52.080 --> 00:53.480 This is going to be an array. 00:53.480 --> 00:58.800 So I'll put a dash in and then I'll say name of Postgres storage. 00:59.520 --> 01:01.000 And then persistent. 01:01.560 --> 01:04.520 Persistent volume claim. 01:06.640 --> 01:07.920 Claim name. 01:08.120 --> 01:11.960 And this is going to be the name of the claim that we had just put together in the other file. 01:12.200 --> 01:15.360 It's name was database persistent volume claim. 01:15.920 --> 01:22.200 So the claim name will be database persistent volume claim. 01:26.680 --> 01:27.040 Okay. 01:27.040 --> 01:32.840 So this right here is what sets up the request on the pod to reach out to Kubernetes and say I need 01:32.840 --> 01:38.160 some type of long term storage that meets all the requirements that are laid out inside of this database 01:38.160 --> 01:40.040 persistent volume claim object. 01:40.040 --> 01:42.360 And that's what we just put together over here. 01:43.000 --> 01:47.600 So this line alone is what's going to make Kubernetes realize that it needs to go over to either the 01:47.600 --> 01:48.560 local hard drive. 01:48.680 --> 01:53.280 If we are in the case of your local environment or some cloud provider, in the case of being deployed 01:53.280 --> 02:00.360 in production and say, hey, I need to somehow source or somehow get some slice of storage that has 02:00.760 --> 02:03.970 this access mode and storage of two gigabytes. 02:04.730 --> 02:07.890 So all this is going to do right here is allocate that storage. 02:08.050 --> 02:12.930 Once we allocate that storage, once we get it available, we need to actually assign it for use by 02:12.930 --> 02:15.690 all the different containers that are in use by our pod. 02:16.090 --> 02:20.970 So in addition to this volume section right here, we're also going to add on some config to our container 02:20.970 --> 02:22.090 section as well. 02:22.850 --> 02:26.570 So inside my container section I'm going to add in a new line here. 02:26.570 --> 02:30.490 And I'm going to get on the same indentation level as name image and ports. 02:30.770 --> 02:33.330 And I'll say volume mounts. 02:34.490 --> 02:37.810 So this is going to say hey all right we just got access to the storage. 02:37.810 --> 02:40.970 And here's how I want it to be used inside of my container. 02:41.490 --> 02:44.290 So I'm going to add in a dash here because this is an array. 02:44.290 --> 02:46.730 We can have multiple volume mounts on a single container. 02:47.170 --> 02:53.610 I'll give it a name of Postgres Postgres storage. 02:53.650 --> 02:55.530 Now this right here is the most important part. 02:55.730 --> 03:00.410 Notice how the volume name and the volume mount name are identical. 03:00.610 --> 03:05.650 So when you put the name right here, it means go back out to the volumes entry Century and find some 03:05.650 --> 03:08.410 piece of storage that we just asked Kubernetes for. 03:08.650 --> 03:11.730 In this case, it's going to find this piece of storage right here. 03:11.890 --> 03:15.290 And that piece of storage is going to be used for this particular volume mount. 03:17.050 --> 03:19.370 We're then going to put in a mount path. 03:19.730 --> 03:24.570 The mount path is designating where inside the container this storage should be made available. 03:25.090 --> 03:28.170 So in other words we're going to put in a little folder reference right here. 03:28.170 --> 03:33.210 And then anything that the container stores at that folder or inside that directory will be actually 03:33.410 --> 03:35.210 stored inside of our volume. 03:35.410 --> 03:39.130 Remember this is at the end of the day, pretty darn similar to the Docker volumes that we had used 03:39.130 --> 03:39.770 previously. 03:40.250 --> 03:46.450 So for the mount path, we're going to designate the data directory that Postgres uses for storing data 03:46.450 --> 03:49.330 on the hard drive, because that's the actual data that we want to back up. 03:49.330 --> 03:53.090 We want to back up all the data that Postgres is storing on the hard drive. 03:53.690 --> 04:01.010 The default storage location for Postgres is var lib PostgreSQL slash data like so. 04:03.890 --> 04:06.770 Okay, now for a normal volume that would be it. 04:06.770 --> 04:10.970 So if this was just a normal application where we're just trying to set up some persistent storage, 04:10.970 --> 04:13.690 that's really all we have to do with Postgres. 04:13.730 --> 04:15.130 Postgres in particular. 04:15.170 --> 04:17.850 We're going to put in one additional little option here. 04:18.250 --> 04:22.890 So as an additional option I'm going to also put in sub path is Postgres like. 04:22.890 --> 04:29.610 So the sub path option means that any data inside the container that is stored inside of mount path 04:29.730 --> 04:35.810 is going to be stored inside of a folder called Postgres, inside of the actual persistent volume claim. 04:36.490 --> 04:41.610 So if we ran our application for some amount of time and then save some data to our Postgres database 04:41.610 --> 04:46.650 and then eventually opened up our persistent volume, we would see that all the data that was saved 04:46.650 --> 04:52.090 to this folder is nested inside of a folder called Postgres inside the persistent volume. 04:52.370 --> 04:55.570 Now, like I said, this is something very specific for Postgres. 04:55.610 --> 05:00.850 It's just because if you try to start up Postgres by default with something that it thinks is a volume 05:00.850 --> 05:03.610 mount, it's going to say, hey, I don't want to save data here. 05:04.010 --> 05:08.860 And so by having Postgres instead save data into a sub folder inside there. 05:08.860 --> 05:11.100 It's going to override that default behavior. 05:11.460 --> 05:14.740 Now saving data into a volume with Postgres is totally fine. 05:14.780 --> 05:15.420 Totally fine. 05:15.420 --> 05:19.900 It's just that Postgres in some cases thinks that you're not necessarily working with Docker. 05:19.940 --> 05:20.340 It gets. 05:20.380 --> 05:21.140 It's a long story. 05:21.140 --> 05:22.220 Let's just leave it at that. 05:22.300 --> 05:24.700 This is just some very particular stuff around Postgres. 05:24.740 --> 05:28.620 Probably not super interesting to you or what you're going to be working on in your own application. 05:28.620 --> 05:29.820 So I'm just going to stop right there. 05:30.220 --> 05:30.540 All right. 05:30.540 --> 05:31.580 So that's pretty much it. 05:32.420 --> 05:33.900 Let's do a very quick review here. 05:33.900 --> 05:39.740 We put together the persistent volume claim that tells Kubernetes that we want to find a storage option 05:39.740 --> 05:41.100 with these requirements. 05:41.540 --> 05:46.820 When we put together our Pod template we said we want to have a volume available that matches these 05:46.820 --> 05:47.660 requirements. 05:47.860 --> 05:53.300 And then inside the container we put together some actual options to say take that volume and make it 05:53.300 --> 05:56.180 available inside of this very particular container. 05:56.380 --> 05:57.620 So that's the entire story. 05:57.660 --> 05:58.980 Let's take a quick pause right here. 05:58.980 --> 06:03.620 When we come back to the next section, we're going to try to apply all these updated config files and 06:03.620 --> 06:06.260 just make sure that everything is working the way we expect. 06:06.260 --> 06:08.540 So quick pause and I'll see you in just a minute.