I have K8s deployed on an EC2 based cluster,
There is an application running in the deployment, and I am trying to figure out the manifest files that were used to create the resources,
There were deployment, service and ingress files used to create the App setup.
I tried the following command, but I'm not sure if it's the correct one as it's also returning a lot of unusual data like lastTransitionTime, lastUpdateTime and status-
kubectl get deployment -o yaml
What is the correct command to view the manifest yaml files of an existing deployed resource?
There is no specific way to do that. You should store your source files in source control like any other code. Think of it like decompiling, you can do it, but what you get back is not the same as what you put in. That said, check for the last-applied annotation, if you use kubectl apply that would have a JSON version of a more original-ish manifest, but again probably with some defaulted fields.
You can try using the --export flag, but it is deprecated and may not work perfectly.
kubectl get deployment -o yaml --export
Refer: https://github.com/kubernetes/kubernetes/pull/73787
KUBE_EDITOR="cat" kubectl edit secrets rook-ceph-mon -o yaml -n rook-ceph 2>/dev/null >user.yaml
Related
I applied a file xyz.yml sometime ago in EKS (Amazon elastic kubernetes service cluster) to deploy a statefulset pod from my local machine. This file is versioned in GitHub. However, there were few manual applies made using kubectl for this file to the kubernetes cluster after that, so it looks like the source file i have right now in GitHub might be out of sync from the cluster.
Is there a safe and easy way to retrieve this file in yaml directly from the cluster using kubectl so that i can use that from now in my GitHub source code. I do not want to make changes in my GitHub source code and then apply them to the cluster as the file might be out of sync.
If somehow i could directly retrieve the file in YAML from the kubernetes cluster, that would really help solve the problem. I tried --dry-run or kubectl diff but don't seem to be helping.
I am new to kubernetes, hence do not want to experiment with commands directly on the cluster.
Any help here would be greatly appreciated.
Cheers,
Ashley
You can try with edit:
kubectl -n <namespace name> edit [deployment, pod, svc] <name>
You can get the current YAML of individual resources with:
kubectl get <resource> -o yaml
But you can't get all the resources that you created with this file at once because Kubernetes doesn't keep track of the manifest files in which the resource definitions were supplied.
So you would need to check which resources were created by your file and get them individually as above. Or if all the resources in this file have common labels, perhaps you could get them more easily by these labels.
I am looking to apply existing annotations on a Kubernetes resource to the underlying YAML configuration files. For example, this command will successfully find all pods with a label of "app=helloworld" or "app=testapp" and annotate them with "xyz=test_anno":
kubectl annotate pods -l 'app in (helloworld, testapp)' xyz=test_anno
However, this only applies the annotations to the running pods and doesn't change the YAML files. How do I force those changes to the YAML files so they're permanent, either after the fact or as part of kubectl annotate to start with?
You could use the kubectl patch command with a little tricks
kubectl patch $(k get po -l 'app in (helloworld, testapp)') -p '{"metadata":{"annotations":{"xyz":"test_anno"}}}'
TLDR: My understanding from learning all about K8s is that you need lots and lots of yaml files, however, I just deployed an app to a K8s clusters with 0 yaml files and it succeeded. Why is that? Does google cloud or K8s have defaults it uses when the app does not have any yaml file settings?
Longer:
I have a dockerized spring app that I deployed to a google cloud cluster I created via the UI.
It had 0 yaml files in there, so my expectation that kubectl deploy would fail, however, it succeeded and my stateless app is up there chugging away.
How does that work?
Well the gcp created for you in the background. I assume you pushed your docker image or CI to cluster and from there you just did few clicks right? same stuff you can do it on openshift environment. but in the background yaml file get's generated. if you edit the pod on your UI you will see that yaml file.
as above #Volodymyr Bilyachat said you can create deployment via imparative way or using declarative way(yaml). I would suggest always use declarative way.
you can see your deployment yaml file which you created from UI by doing
kubectl get deployment <deployment_name> -o yaml
kubectl get deployment <deployment_name> -o yaml > name.yaml #This will output your yaml file into name.yaml file
You can run your containers/pods using plain commands.
kubectl run podname --image=name
As you said 0 yaml files. But main idea of those files that you push them to source control and run test them via different environments using CI/CD.
Other benefit of yaml files that you can share configuration and someone else will be able to create infrastructure without having to write anything. Here is example how you can run elasticsearch with one command
kubectl apply -f https://download.elastic.co/downloads/eck/1.2.0/all-in-one.yaml
How to find the location of a kubernetes object's definition file.
I know the name of a kubernetes deployment and want to make some changes directly to its definition file instead of using 'kubernetes edit deployment '
The object definitions are stored internally in Kubernetes in replicated storage that's not directly accessible. If you do change an object definition, you would still need to trigger the rest of the Kubernetes update sequence when an object changes.
Typical practice is to keep the Kubernetes YAML files in source control. You can then edit these locally, and use kubectl apply -f to send them to the cluster. If you don't have them then you can run commands like kubectl get deployment depl-name -o yaml to get them out, and then check in the results to your source control repository.
If you really want to edit YAML definitions in an imperative, non-reproducible way, kubectl edit is the most direct thing you can do.
You could execute kubectl get deployment <deployment-name> -o yaml to get the deployment definition in a yaml format (or -o json to get in a json format), save that to a file, edit the file and apply the changes.
In a step-by-step guide would be:
Run kubectl get deployment deployment-name -o yaml > deployment-name.yaml
Edit and save the deployment-name.yaml using the editor of your preference
Run kubectl apply -f deployment-name.yaml to apply the changes
It's all stored in etcd
Nodes
Namespaces
ServiceAccounts
Roles and RoleBindings, ClusterRoles / ClusterRoleBindings
ConfigMaps
Secrets
Workloads: Deployments, DaemonSets, Pods, …
Cluster’s certificates
The resources within each apiVersion
The events that bring the cluster in the current state
Take a look at this blog post
I created a .yaml file following this tutorial. You deploy the web service with kubectl apply -f shopfront-service.yaml. So far so good. The author says nothing though about how to tear everything down.
With TerraForm or CloudFormation you use the same .yaml file to remove all resources. I would think that K8 would also support cleaning up using the same .yaml file, but I can't find any way to do this.
Is there a way to delete resources with the same .yaml file used to create the deployment?
kubectl delete -f shopfront-service.yaml
see kubectl delete docs