Red Hat OpenShift Red Hat OpenShift 4, 7 Jan 2020

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From YouTube: Workload Demo: PostgreSQL on OpenShift 4 with OpenShift Container Storage 4

Description

Chris Blum, architect, demonstrates OpenShift Container Storage 4 stateful applications with Rails & PostgreSQL.
Learn more: openshift.com/storage

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Hi I'm Chris, bloom and I'm architect in a storage video today I'm going to talk about a traditional stateful applications on OpenShift foreign, using appreciative, container storage for, and we will show this on a little demo that leverages tutorials and Postgres application.

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Today we're going to talk about what we consider traditional stateful applications, why you should use OCS for these applications and then on going to show you this quick demo with the rails and Posterous application.

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So what do we consider traditional state file applications? These are applications that typically store stayed and rely on that state to be present. So these applications generally, when you install them, have an interface where they initialize their back-end storage and typically, if it's a database, they put in tables and indexes and all that and then once users use these applications, the data that they rely on it grows and you have to keep it since they're traditional applications.

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They are not necessarily aware that they're running inside of openshift and they also done typically leverage open, sherek abilities, api's such as secrets or config maps, but they might be using them indirectly without knowing that they're. Actually using them, so why should I use OCS for my stateful applications? Ocs has a very easy way to install itself.

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It's built upon battle-tested software like rogue and safe that have already been used for many many years by customers in productive environments, and it has been shown that using the software, it's very easy to scale out and not only increase the capacity which is easy, but also increase the performance. Almost literally then. Obviously, using OCS you get Red Hat support and since that software Safin ruk start software is it's so popular. We can also look on a very large community that helps us in certain areas. So going forward with the demo.

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We're going to see is a deployment of a typical rails application that relies on a Postgres database back-end, so Posterous mentions the state of the application.

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Application itself is not stable and phosphorus is backed by OCS to retain and to show you that this is actually true we're going to scale down the application in the end to simulate fault, and then we scale it back up so that it comes back up and we show that our data is actually safe. So, let's head over there for this we're going to use this example here, then I've prepared and we're just going to deploy this application that I just like we have them in the example here.

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This will take a bit but I'm going to fast forward the video. So you don't have to wait.

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With the OSI status, we can theoretically check on our application and we do see that it's currently still new, but we can also see that we already have a PVC for Postgres database and that is already bound. Sir. The backend storage system, which is backed by cefr BD, has already created this volume and it's ready for the pot to use it. So, let's check how far the deployment this already okay, so our Posterous deployment has finished. The database is ready to be used.

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Rent application is currently in the build phase and, as you can see in the guide here, half the bill we deploy have a hook and then we actually deploy our application. So we'll come back in a second okay, as we can see now the Postgres part it is running and the rails application has gone through its build opponent, hooks it up, and it's not also running. So we are good to continue and to continue. We will figure out how we can reach our application by checking on the routes, and our routes looks like this.

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In this example, we see that we have to append such articles to login. We are using these credentials here, so username open share password secret. Let's do that.

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We click a new article and.

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We use a title like I'm running on OCS, and this is great, so this is our first article I'm not going to comment on it right now, so we go back to the other year and we see that this is a great article.

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So this is our first state as you've seen we have gone through an in it face on the roads, application that I've prepared the Posterous database and now, as we use it, we created our very first data and that will also be retained in a postscript database. So now, let's look a little bit more on our storage back-end and for this let's first get an overview of our PVCs resistant, rolling claim that we already saw before and now it's names phosphorus, it's bound. It's using cell RBD to look at settle RBD a little bit closer.

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We will go into the Ceph route to what and.

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This is how we get in there. Then we execute commands like SEF, DF or Raiders F, which will both give us a good overview of how our storage is used. We do see that our search class is based on SSD disks. We do have lot of ports, but we're currently only interested in this pool because it matches wide the storage gas is using, so Safari D is backed by the safe black ball, and so let's look at the images that are inside of this pool.

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We do this by executing RVD with minus B, which is for pool.

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And we do see that we have two images and based on the PVC name. I would assume that it's this volume that is basing our Posterous database.

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So we can look at this a little bit closer using info.

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And we do see that sizes 5 gigabytes, so this is very, very likely our image, let's all the PVCs in all namespaces like this, then we can see that there are actually two PVCs that are using the OCS storage class and that's our phosphorous application and also the Nuba database. Nuba database is using 50 gigabytes. So since this is five gigabytes, this is indeed our ACEF ammonium that were exporting to our application. So now we have our application up here and we do see that the articles are there and everything is good.

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So, let's simulate a little bit of full. We go over here, and this is the web UI of a pinch of four, and we are looking now at the replication controllers inside of our project that we created called my database app, and we do have here the replication controllers for phosphorus and rails.

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So what I'm going to do is I'm going to watch the pots here and here I'm going to change the count so I'm going to decrease the amount of phosphorus databases that I say we need this will terminate our Posterous cluster.

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So what the replication controller did is it started a new Posterous and, as you can see, even though it's a completely new database, we now have they'll, have our articles out there and we're perfectly fine with this.

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So this concludes our little demo of rails application using Posterous that is backed by OCS. As you can see, it's fairly simple to do that, and even to demo this in a matter of ten minutes, and if you have questions, please use the Q&A part and I'm happy to answer there.