1 00:00:00,000 --> 00:00:13,033 Hi, Lets understand about Chart Hooks. Already we discussed about chart hooks where we can add a hook to do the testing 2 00:00:13,033 --> 00:00:18,933 which will not get deployed as a component as a part of kubernetes cluster, but will get executed so 3 00:00:18,933 --> 00:00:22,533 that I can utilize that particular execution for testing. 4 00:00:22,533 --> 00:00:30,133 Let's have a detailed discussion about hooks where hooks can get triggered at various stages of the chart 5 00:00:30,133 --> 00:00:37,299 lifecycle like pre-install, post-install, pre-delete, pre-upgrade, post-uprade, pre-rollback 6 00:00:37,300 --> 00:00:39,400 Post-rollback. As the name suggest 7 00:00:39,400 --> 00:00:47,400 I can get the hook executed before or after a specific stage of the chart, and I can make use of that 8 00:00:47,400 --> 00:00:51,266 particular execution for testing purpose to make sure we do 9 00:00:51,266 --> 00:00:56,132 have all the prerequired requisites for example, before doing the 10 00:00:56,133 --> 00:01:03,299 upgrade, I can make some process to get triggered and even for example, post-rollback I can trigger some 11 00:01:03,300 --> 00:01:09,433 process to get invoked so that the other processes or other pods can take care of it. 12 00:01:09,433 --> 00:01:16,333 Let's see through some example, let me go ahead and create a chart with the name hooktest. As a part 13 00:01:16,333 --> 00:01:21,033 of the templates within hooktest I can get into the templates. 14 00:01:21,033 --> 00:01:24,133 Here's where I'm going to create the hooks. 15 00:01:24,133 --> 00:01:28,133 I can mention a particular component as a hook by adding an annotation. 16 00:01:28,133 --> 00:01:34,299 saying that is a hook and at what state that particular hook should get triggered. 17 00:01:34,300 --> 00:01:37,966 Let me go ahead and create pre-install and post install 18 00:01:37,966 --> 00:01:43,199 hook. For that I will be creating separate yaml files. Let me create 19 00:01:43,200 --> 00:01:53,600 yaml file and add the content. Here I do have the annotation with the key 20 00:01:53,600 --> 00:01:57,000 It is a hook and at what stage it should get triggered. 21 00:01:57,000 --> 00:02:03,766 Basically it is going to start a container and that's going to sleep for fifteen seconds and get stopped. 22 00:02:03,766 --> 00:02:13,999 The same way let me go ahead and create another hook. Let me add the content for this specific hook. 23 00:02:14,000 --> 00:02:16,800 Here I have mentioned the hook as a post install 24 00:02:16,800 --> 00:02:23,633 So after the installation of the helm chart this particular hook will get triggered and within the 25 00:02:23,633 --> 00:02:29,366 hook it's going to echo this particular statement and sleep for ten seconds. 26 00:02:29,366 --> 00:02:32,966 Now, I do have two hooks. 27 00:02:32,966 --> 00:02:41,566 Let me go ahead and check the components as a part of kubernetes cluster. 28 00:02:41,566 --> 00:02:51,066 I did not have any pods related to this particular chart. Let me install this hook. 29 00:02:51,066 --> 00:02:57,532 I'm installing with the command helm install hooktest install and then the chart resources. 30 00:02:57,533 --> 00:03:00,899 So it's going to trigger the pre-install hook. 31 00:03:00,900 --> 00:03:07,233 And since we gave the sleep command it's going to sleep for certain duration, then the actual chart 32 00:03:07,233 --> 00:03:10,299 will get installed. Then post install 33 00:03:10,300 --> 00:03:17,900 hook should get triggered. Pre-install hook is successful then the pod should get installed 34 00:03:17,900 --> 00:03:21,300 Yes, the Chart installation is successful and it is deployed. 35 00:03:21,300 --> 00:03:25,933 Let me check the status of the chart helm list 36 00:03:25,933 --> 00:03:28,966 hooktest install is successfully installed. 37 00:03:28,966 --> 00:03:37,499 Let me check the status of this particular deployment, helm status and then the name of the deployment. 38 00:03:37,500 --> 00:03:46,633 It is successfully deployed. Now, let me go ahead and get the status of the pods. 39 00:03:46,633 --> 00:03:53,466 So if you look at very carefully, this is the pod that got deployed as a part of this particular chart 40 00:03:53,466 --> 00:03:58,299 hooktest install and two pods that got executed 41 00:03:58,300 --> 00:04:03,000 And it got over. It came to the status completed. 42 00:04:03,000 --> 00:04:08,200 Now, let me go ahead and get more description about this particular pod that is pre-install hook 43 00:04:08,200 --> 00:04:16,600 pod and grep the annotation tag started and finished information from describe kubectl describe the 44 00:04:16,600 --> 00:04:22,600 pre-install hook pod and grep the annotation started and finished. 45 00:04:22,600 --> 00:04:26,200 Values. So within that, this is the started 46 00:04:26,200 --> 00:04:31,133 So it started in 22 seconds and got over in 37 seconds. 47 00:04:31,133 --> 00:04:37,266 Now, let me get the details about this particular pod and get the information. 48 00:04:37,266 --> 00:04:42,366 So this particular pod is still running. So it started in 42 seconds. 49 00:04:42,366 --> 00:04:49,599 So basically after the pre-install hook got over it started its deployment and it successfully 50 00:04:49,600 --> 00:04:58,300 started in 42 second. Now, let me get the details about post-install hook. 51 00:04:58,300 --> 00:05:01,000 Post-install hook started in 41th second. 52 00:05:01,000 --> 00:05:07,566 So basically, like with microseconds, if you consider the post-install it started and it got over 53 00:05:07,566 --> 00:05:11,799 in 51 seconds. So that's the overlap. 54 00:05:11,800 --> 00:05:14,766 So don't worry about this particular overlap. So what's going to happen 55 00:05:14,766 --> 00:05:19,932 Pre-install hook will get triggered before the deployment of the pod and post-install hook will 56 00:05:19,933 --> 00:05:22,799 get triggered after the deployment of the pod. 57 00:05:22,800 --> 00:05:29,800 And I can make use of this particular staged execution to validate as well as to verify the resources or any pre-check 58 00:05:29,800 --> 00:05:37,300 I wanted to do before or after the deployment of the charts. So in a quick summary we discussed about the 59 00:05:37,300 --> 00:05:42,533 introduction about hooks and how to make use of the pre-install and post-install hook 60 00:05:42,533 --> 00:05:46,166 Now let me go ahead and clear this particular deployment. 61 00:05:46,166 --> 00:05:54,299 Let me delete the deployment using helm delete and the name of the deployment. 62 00:05:54,300 --> 00:06:02,333 Also, I need to explicitly delete the completed pods. 63 00:06:02,333 --> 00:06:09,299 So this completed pods I need to explicitly delete so I'll use the command kubectl delete and then 64 00:06:09,300 --> 00:06:14,666 name of the pod, the same way I will delete the post-install hook pod as well. 65 00:06:14,666 --> 00:06:23,066 So both are deleted. Now, let me get the list of pods. 66 00:06:23,066 --> 00:06:27,666 So I do not have any pods related to this hook. The same way 67 00:06:27,666 --> 00:06:33,699 I can make the hooks to get triggered for the jobs as well. Within Kubernetes 68 00:06:33,700 --> 00:06:39,866 We do have another component called Jobs when the jobs getting executed before and after execution 69 00:06:39,866 --> 00:06:42,632 I can make the hooks to get triggered 70 00:06:42,633 --> 00:06:45,699 Let's see that in the next example as well as 71 00:06:45,700 --> 00:06:51,733 We can set the weightage for the hooks also. In case if I have multiple hooks which hook should get 72 00:06:51,733 --> 00:06:55,299 triggered based on the weightage it can decide that example 73 00:06:55,300 --> 00:06:57,700 also we will be seeing in the future lecture.