1 00:00:02,160 --> 00:00:04,640 So this was an important module. 2 00:00:04,640 --> 00:00:07,250 We got our hands dirty with Kubernetes 3 00:00:07,250 --> 00:00:10,670 and we first of all learned, what we need to set up, 4 00:00:10,670 --> 00:00:13,700 the cluster and the infrastructure for the cluster, 5 00:00:13,700 --> 00:00:15,360 the software on the cluster 6 00:00:15,360 --> 00:00:17,690 and what Kubernetes does will do. 7 00:00:17,690 --> 00:00:19,780 We also learned that there are tools 8 00:00:19,780 --> 00:00:22,030 that can help us with setting up the cluster. 9 00:00:22,030 --> 00:00:23,940 Locally that would be Minikube 10 00:00:23,940 --> 00:00:25,930 to give us this development environment 11 00:00:25,930 --> 00:00:27,580 and on a cloud provider, 12 00:00:27,580 --> 00:00:29,540 that's something we're going to explore later, 13 00:00:29,540 --> 00:00:31,513 we'll also have tools that help us. 14 00:00:32,409 --> 00:00:34,290 Now since we work locally, 15 00:00:34,290 --> 00:00:35,610 we started with creating 16 00:00:35,610 --> 00:00:37,900 such a local development environment 17 00:00:37,900 --> 00:00:41,380 with the help of Minikube to get a local cluster 18 00:00:41,380 --> 00:00:44,280 in a virtual machine, running on our local machine 19 00:00:44,280 --> 00:00:46,840 and we installed the Kube control tool, 20 00:00:46,840 --> 00:00:48,420 which we will always need, 21 00:00:48,420 --> 00:00:50,520 not just if we work locally, 22 00:00:50,520 --> 00:00:53,050 because that's our communication device 23 00:00:53,050 --> 00:00:56,750 for sending instructions to the Kubernetes cluster. 24 00:00:56,750 --> 00:00:59,170 Now we learned that Kubernetes works 25 00:00:59,170 --> 00:01:01,080 with so-called objects. 26 00:01:01,080 --> 00:01:03,660 So the different resources we have running 27 00:01:03,660 --> 00:01:08,010 in a Kubernetes clusters are in the end, all such objects. 28 00:01:08,010 --> 00:01:10,550 And we can create them in two different ways, 29 00:01:10,550 --> 00:01:13,470 imperatively or declaratively. 30 00:01:13,470 --> 00:01:15,500 Now with the imperative approach, 31 00:01:15,500 --> 00:01:20,380 we executed commands like, create deployment, 32 00:01:20,380 --> 00:01:23,080 giving it a name and specifying the image 33 00:01:23,080 --> 00:01:24,723 which should be used. 34 00:01:26,430 --> 00:01:27,810 Something like this. 35 00:01:27,810 --> 00:01:29,850 And this worked just fine. 36 00:01:29,850 --> 00:01:32,520 It just was quite a bunch of typing. 37 00:01:32,520 --> 00:01:35,090 Of course we did not just do this for deployments, 38 00:01:35,090 --> 00:01:38,630 but then for example, also to expose a deployment 39 00:01:38,630 --> 00:01:42,150 by creating a service where we then specify 40 00:01:42,150 --> 00:01:46,543 a port and also the type of service. 41 00:01:47,530 --> 00:01:49,820 These were the imperative commands we saw. 42 00:01:49,820 --> 00:01:52,760 And we did not just see the commands for creating things, 43 00:01:52,760 --> 00:01:55,700 but also for deleting or for setting a new image 44 00:01:55,700 --> 00:01:58,973 and therefore for updating currently running deployments. 45 00:01:59,820 --> 00:02:03,120 But then we also learned about the more modern 46 00:02:03,120 --> 00:02:07,510 and a bit more convenient declarative approach. 47 00:02:07,510 --> 00:02:09,850 There you write down your configuration 48 00:02:09,850 --> 00:02:13,640 in these YAML files and you then simply apply them 49 00:02:13,640 --> 00:02:17,280 with the Kube control tool and the apply command. 50 00:02:17,280 --> 00:02:21,040 And you can apply just one file, as you learned 51 00:02:21,040 --> 00:02:23,613 or also multiple files at once. 52 00:02:24,510 --> 00:02:27,240 And whenever you make a change to one of these files 53 00:02:27,240 --> 00:02:29,690 and you reapply it, the cool thing is, 54 00:02:29,690 --> 00:02:32,550 that only these parts will be changed automatically 55 00:02:32,550 --> 00:02:36,423 by Kubernetes on the running application in your cluster. 56 00:02:37,330 --> 00:02:40,080 Now you can also delete resources 57 00:02:40,080 --> 00:02:42,090 that were created based on files 58 00:02:42,090 --> 00:02:47,090 by using delete with the dash F option like this. 59 00:02:47,580 --> 00:02:49,040 And of course, you also learned 60 00:02:49,040 --> 00:02:52,200 that you can merge multiple definitions into one file, 61 00:02:52,200 --> 00:02:55,870 in case you don't want to manage multiple files 62 00:02:55,870 --> 00:02:59,732 and also to make it easy to see which services 63 00:02:59,732 --> 00:03:03,563 and deployments and maybe other resources belong together. 64 00:03:04,540 --> 00:03:06,330 Now, when it comes to these files, 65 00:03:06,330 --> 00:03:09,140 we had a look at how they are structured 66 00:03:09,140 --> 00:03:11,850 and what the different options do in here, 67 00:03:11,850 --> 00:03:14,588 how labels and selectors work together 68 00:03:14,588 --> 00:03:17,470 to connect different resources, 69 00:03:17,470 --> 00:03:20,200 how we define paths and containers, 70 00:03:20,200 --> 00:03:24,370 how we can control the health checks which are performed, 71 00:03:24,370 --> 00:03:29,120 how we can control when images are pulled and so on. 72 00:03:29,120 --> 00:03:33,310 And I also pointed you at the official API reference, 73 00:03:33,310 --> 00:03:35,290 which can be useful for finding out 74 00:03:35,290 --> 00:03:37,360 which options can be set 75 00:03:37,360 --> 00:03:40,500 and what these different options do. 76 00:03:40,500 --> 00:03:42,520 Though, I also of course mentioned 77 00:03:42,520 --> 00:03:45,580 that many of these options will rarely be needed. 78 00:03:45,580 --> 00:03:48,390 So don't be overwhelmed by the long list 79 00:03:48,390 --> 00:03:52,620 of options that can be set on certain objects. 80 00:03:52,620 --> 00:03:53,570 And with that, 81 00:03:53,570 --> 00:03:56,710 we get all the important Kubernetes basics down. 82 00:03:56,710 --> 00:03:58,230 We know the big picture 83 00:03:58,230 --> 00:04:00,730 and the general architecture or philosophy 84 00:04:00,730 --> 00:04:05,010 behind Kubernetes, but then even more important than that, 85 00:04:05,010 --> 00:04:09,120 we also now know how to work with this architecture 86 00:04:09,120 --> 00:04:12,240 and how to bring this big picture to life. 87 00:04:12,240 --> 00:04:15,080 So now we'll dig deeper into Kubernetes 88 00:04:15,080 --> 00:04:17,589 and have a look at a couple of key problems 89 00:04:17,589 --> 00:04:20,529 which you'll face in almost any application, 90 00:04:20,529 --> 00:04:24,233 so that you're also prepared to build such applications.