if i apply some config to kubernetes with kubectl like:
kubectl apply -f config.yaml
Is there any command to read or show this config? I need update some things in config, but I'm on another pc and I dont have configs here, so I need get them from kubectl first, is it possible? Thanks!
simple way : cat the file
cat config.yaml
indirect way:
kubectl apply -f config.yaml --dry-run=client -o yaml
for brevity
kubectl create -f config.yaml --dry-run=client -o yaml
You can copy ~/.kube/config from one machine to another, you can then access your cluster using kubectl on the other machine. From there you can do kubectl get configmap <name> -o yaml > config.yaml, edit the saved config.yaml and re-apply with kubectl apply -f config.yaml.
I was wondering if there is an easier way to create daemonsets in k8s other than yaml files.
For eg, for pods we have kubectl run --generator=run-pod/v1 command. I was wondering if there is something similar for DS.
Thanks in advance.
There is no such quick kubectl create type command for creating daemonsets. But you can do it in some other way.
One way to do this is:
$ kubectl create deploy nginx --image=nginx --dry-run=client -o yaml | \
sed '/null\|{}\|replicas/d;/status/,$d;s/Deployment/DaemonSet/g' > nginx-ds.yaml
$ kubectl apply -f nginx-ds.yaml
If you don't want to save the yaml data to any file, here's how you can do this:
$ kubectl create deploy nginx --image=nginx --dry-run=client -o yaml | \
sed '/null\|{}\|replicas/d;/status/,$d;s/Deployment/DaemonSet/g' | \
kubectl apply -f -
You have your daemonset now.
What we are doing here is: at first we're creating a deployment yaml and then replacing kind: Deployment with kind: DaemonSet and remove replicas: 1 from the deployment yaml.
Thats's how we get yaml for daemonset.
You can access Kubernetes Documentation for DaemonSets. You could use the link and get examples of DaemonSet yaml files. However there is no way you could create a Daemonset by imperative way. You could create a deployment specification and change the deployment specification to DaemonSet specification. You need to change the kind to Daemonset, remove strategy, replicas and status fields. That would do.
I've created several resources using k8s Ansible module. Now I'd like to export the resources into Kubernetes manifests (so I don't need to use Ansible anymore). I've started by exporting a Service:
$ kubectl get svc myservice -o yaml --export > myservice.yaml
$ kubectl apply -f myservice.yaml
Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
service/myservice configured
Why do I get the the warning? And why there's service/myservice configured and not service/myservice unchanged? Is there a better way to export resources?
You're doing right, don't worry about the warning.
If you want to get rid of it, you have to delete all the generation, selfLink and so on keys.
Yes, you are doing it right.
Let me show you small trick:
kubectl get svc myservice -o yaml --export | sed -e '/status:/d' -e '/creationTimestamp:/d' -e '/selfLink: [a-z0-9A-Z/]\+/d' -e '/resourceVersion: "[0-9]\+"/d' -e '/phase:/d' -e '/uid: [a-z0-9-]\+/d' > myservice.yaml
Will generate proper yaml file without status, creationTimestamp, selfLink, resourceVersion, phase and uid.
You get the warning because you're using kubectl apply on a resource that you previously created with kubectl create. If you create the initial Service with kubectl apply, you shouldn't get the warning.
The configured instead of unchanged might be because of some metadata or generated data that is also included in the output of kubectl get svc myservice -o yaml --export.
I have deployed an application into Kubernetes using the following command.
kubectl apply -f deployment.yaml -n <NAMESPACE>
I have my deployment content in the deployment yaml file.
This is working fine. Now, I have updated few things in the deployment.yaml file and hence would like to update the deployment.
Option 1:- Delete and deploy again
kubectl delete -f deployment.yaml -n <NAMESPACE>
kubectl apply -f deployment.yaml -n <NAMESPACE>
Option 2:- Use set to update changes
kubectl set image deployment/nginx-deployment nginx=nginx:1.91
I don't want to use this approach as I am keeping my deployment.yaml file in GitHUB.
Option 3:- Using edit command
kubectl edit deployment/nginx-deployment
I don't want to use the above 3 options.
Is there any way to update the deployment using the file itself.
Like,
kubectl update deployment.yaml -n NAMESPACE
This way, I will make sure that I will always have the latest deployment file in my GitHub repo.
As #Daisy Shipton has said, what you want to do could be simplified with a simple command: kubectl apply -f deployment.yaml.
I will also add that I don't think it's correct to utilize the Option 2 to update the image utilized by the Pod with an imperative command! If the source of truth is the Deployment file present on your GitHub, you should simply update that file, by modifying the image that is used by your Pod's container there!
Next time you desire to update your Deployment object, unless you don't forget to modify the .yaml file, you will be setting the Pods to use the previous Nginx's image.
So there certainly should exist some restriction in using imperative commands to update the specification of any Kubernetes's object!
I am trying to deploy my app to Kubernetes running in Google Container
Engine.
The app can be found at: https://github.com/Industrial/docker-znc.
The Dockerfile is built into an image on Google Container Registry.
I have deployed the app in Kubernetes via the + button. I don't have the YAML
for this.
I have inserted a Secret in Kubernetes for the PEM file required by the app.
How do I get the YAML for the Deployment, Service and Pod created by
Kubernetes by filling in the form?
How do I get the Secret into my Pod for usage?
To get the yaml for a deployment (service, pod, secret, etc):
kubectl get deploy deploymentname -o yaml
How do I get the YAML for the Deployment, Service and Pod created by
Kubernetes by filling in the form?
kubectl get deployment,service,pod yourapp -o yaml --export
Answering #Sinaesthetic question:
any idea how to do it for the full cluster (all deployments)?
kubectl get deploy --all-namespaces -o yaml --export
The problem with this method is that export doesn't include the namespace. So if you want to export many resources at the same time, I recommend doing it per namespace:
kubectl get deploy,sts,svc,configmap,secret -n default -o yaml --export > default.yaml
Unfortunately kubernetes still doesn't support a true get all command, so you need to list manually the type of resources you want to export. You can get a list of resource types with
kubectl api-resources
The same issue is discussed at kubernetes GitHub issues page and the user "alahijani" made a bash script that exports all yaml and writes them to single files and folders.
Since this question ranks well on Google and since I found that solution very good, I represent it here.
Bash script exporting yaml to sub-folders:
for n in $(kubectl get -o=name pvc,configmap,serviceaccount,secret,ingress,service,deployment,statefulset,hpa,job,cronjob)
do
mkdir -p $(dirname $n)
kubectl get -o=yaml --export $n > $n.yaml
done
Another user "acondrat" made a script that do not use directories, which makes it easy to make a kubectl apply -f later.
Bash script exporting yaml to current folder:
for n in $(kubectl get -o=name pvc,configmap,ingress,service,secret,deployment,statefulset,hpa,job,cronjob | grep -v 'secret/default-token')
do
kubectl get -o=yaml --export $n > $(dirname $n)_$(basename $n).yaml
done
The last script does not include service account.
Now that --export is deprecated, to get the output from your resources in the 'original' format (just cleaned up, without any information about the current object state (unnecessary metadata in this circumstance)) you can do the following using yq v4.x:
kubectl get <resource> -n <namespace> <resource-name> -o yaml \
| yq eval 'del(.metadata.resourceVersion, .metadata.uid, .metadata.annotations, .metadata.creationTimestamp, .metadata.selfLink, .metadata.managedFields)' -
Syntax for downloading yaml's from kubernetes
kubectl get [resource type] -n [namespace] [resource Name] -o yaml > [New file name]
Create yaml file from running pod:
kubectl get po -n nginx nginx-deployment-755cfc7dcf-5s7j8 -o yaml > podDetail.yaml
Create replicaset yaml file from running pod:
kubectl get rs -n nginx -o yaml > latestReplicaSet.yaml
Create deployement yaml file from running pod:
kubectl get deploy -n nginx -o yaml > latestDeployement.yaml
Also its possible to use the view-last-applied command e.g.
kubectl apply view-last-applied services --all > services.yaml
which will return all the manifests applied to create services. Also you can specify a certain k8 resource by services/resource-name label.
If you need to get 'clean' export, removing the annotations added by Kubernetes, there's an opensource project that does that by piping the output of kubectl get - https://github.com/itaysk/kubectl-neat.
It removes the timestamp metadata, etc.
kubectl get pod mypod -o yaml | kubectl neat
kubectl get pod mypod -oyaml | kubectl neat -o json
Use this command to get yaml format of your service
kubectl get service servicename -n <namespace> -o yaml
You can put it in some file also
kubectl get service servicename -n <namespace> -o yaml > service.yaml
The following code will extract all your K8s definitions at once and place them on individual folders below the current folder.
for OBJ in $(kubectl api-resources --verbs=list --namespaced -o name)
do
for DEF in $(kubectl get --show-kind --ignore-not-found $OBJ -o name)
do
mkdir -p $(dirname $DEF)
kubectl get $DEF -o yaml \
| yq eval 'del(.metadata.resourceVersion, .metadata.uid, .metadata.annotations, .metadata.creationTimestamp, .metadata.selfLink, .metadata.managedFields)' - > $DEF.yaml
done
done
You can store output of deployed kubernetes service by using below command -
kubectl get svc -n -o yaml > svc-output.yaml
For deployments -
kubectl get deploy <deployment-name> -n <your-namespace> -o yaml > deploy-output.yaml
For Pod -
kubectl get pod <pod-name> -n <your-namespace> -o yaml > pod-output.yaml
You can get your secret details using below command -
kubectl get secret -n -o yaml
In order to use update your deployment file by using below command -
kubectl edit deploy -n
Under your pod template add below -
this will go under pod containers section to mount secret volume to container
volumeMounts:
- name: foo
mountPath: "/etc/foo"
readOnly: true
this will go inside your pod template section in deployment
volumes:
- name: foo
secret:
secretName: mysecret
for the 2nd question regarding the secret, this is from the k8s documentation. see https://kubernetes.io/docs/concepts/configuration/secret/#using-secrets for more info.
Create a secret or use an existing one. Multiple pods can reference the same secret.
Modify your Pod definition to add a volume under spec.volumes[]. Name the volume anything, and have a spec.volumes[].secret.secretName field equal to the name of the secret object.
Add a spec.containers[].volumeMounts[] to each container that needs the secret. Specify spec.containers[].volumeMounts[].readOnly = true and spec.containers[].volumeMounts[].mountPath to an unused directory name where you would like the secrets to appear.
Modify your image and/or command line so that the program looks for files in that directory. Each key in the secret data map becomes the filename under mountPath.
I have used this and it works fine.
Like mentioned above "--export" is one option to get the manifest corresponding to the kubeernetes objects
But "--export" is considered to be buggy and there is a proposal to deprecate it
Currently the better option is to do "-o yaml" or "-o json" and remove the unnecessary fields
The main difference is "--export" is expected to remove the cluster specific settings (e.g. cluster service IP of a k8s service). But it is found to be inconsistent in this regard
All services
kubectl get service --all-namespaces -o yaml > all-service.yaml
All deployments
kubectl get deploy --all-namespaces -o yaml > all-deployment.yaml
We can get the contents associated with any kind from a Kubernetes cluster through the command line if you have the read access.
kubectl get <kind> <kindname> -n <namespace> -o <yaml or json>
For example, if you want to export a deployment from a namespace follow the below command -
kubectl get deploy mydeploy -n mynamespace -o yaml > mydeploy.yaml
kubectl get deploy mydeploy -n mynamespace -o json > mydeploy.json
To get all yaml file deployments backup (not a specific deployment):
kubectl get deployments -n <namespace> -o yaml > deployments.yaml
for getting all yaml file services backup (not a specific deployment):
kubectl get services -n <namespace> -o yaml > services.yaml
enjoy it.
To get YAML for current running deployment on kubernetes, you can run this command:
kubectl get deployment <deployment_name> -o yaml
To generate YAML for deployment you can run the imperative command.
kubectl create deployment <deployment_name>--image=<image_name> -o yaml
To generate and export the deployment you can run the imperative command.
kubectl create deployment <deployment_name>--image=<image_name> --dry-run=client -o yaml > example.yaml
kubectl -n <namespace> get <resource type> <resource Name> -o yaml
With the command above, any resource defined in Kubernetes can be exported in YAML format.
You can try use kube-dump bash script
With this utility, you can save Kubernetes cluster resources as a pure yaml manifest without unnecessary metadata.
GitHub repository
Review of the utility in blog page
We can get yaml for deployed resources using below command.
kubectl get <resource name> -o yaml
OR
kubectl get <resource name> <name of pod> -o yaml
example:-
kubectl get deploy Nginx -o yaml
above commands will give you yaml output.
if you want to store the output into any file you can use below command.
kubectl get pod nginx -o yaml > Nginx-pod.yaml
above command will redirect you output to Nginx-pod.yaml in your courrent directory.
If you need to view and edit the file use:
kubectl edit service servicename
You can get the yaml files of the resources using this command
kubectl -n <namespace> get <resource type> <resource Name> -o yaml
To get the secret into your pod,
use something like this
env
- valueFrom
secretKeyRef:
name: secret_name
key: key_name
or
envFrom
- secretRef:
name: secret_name
Is only minor difference from #Janos Lenart's answer!
kubectl get deploy deploymentname -o yaml > outputFile.yaml will do
I know it is too old to answer, but hopefully, someone will find it helpful.
We can try below command to fetch a kind export from all namespace -
kubectl get <kind> --all-namespaces --export -o yaml