I got admin rights on our cluster and I want to query the config yaml file which is deployed to the cluster, the file is already applied to the cluster and I want to query the file values of networkPolicy I mean all files with kind kind: NetworkPolicy , is it possible to do it from the terminal ?
In small cluster I can do
kubectl get deploy --all-namespaces -o yaml > dep.yaml
but in big cluster there is a lot of file/data ....
To get the YAML manifests of all NetworkPolicy resources in the cluster:
kubectl get netpol --all-namespaces -o yaml
If you need only some of them, you can filter based on label values or field values with the -l/--selector and --field-selector options.
Related
As the kubernetes.io docs state about a Service of type LoadBalancer:
On cloud providers which support external load balancers, setting the
type field to LoadBalancer provisions a load balancer for your
Service. The actual creation of the load balancer happens
asynchronously, and information about the provisioned balancer is
published in the Service's .status.loadBalancer field.
On AWS Elastic Kubernetes Service (EKS) a an AWS Load Balancer is provisioned that load balances network traffic (see AWS docs & the example project on GitHub provisioning a EKS cluster with Pulumi). Assuming we have a Deployment ready with the selector app=tekton-dashboard (it's the default Tekton dashboard you can deploy as stated in the docs), a Service of type LoadBalancer defined in tekton-dashboard-service.yml could look like this:
apiVersion: v1
kind: Service
metadata:
name: tekton-dashboard-external-svc-manual
spec:
selector:
app: tekton-dashboard
ports:
- protocol: TCP
port: 80
targetPort: 9097
type: LoadBalancer
If we create the Service in our cluster with kubectl apply -f tekton-dashboard-service.yml -n tekton-pipelines, the AWS ELB get's created automatically:
There's only one problem: The .status.loadBalancer field is populated with the ingress[0].hostname field asynchronously and is therefore not available immediately. We can check this, if we run the following commands together:
kubectl apply -f tekton-dashboard-service.yml -n tekton-pipelines && \
kubectl get service/tekton-dashboard-external-svc-manual -n tekton-pipelines --output=jsonpath='{.status.loadBalancer}'
The output will be an empty field:
{}%
So if we want to run this setup in a CI pipeline for example (e.g. GitHub Actions, see the example project's workflow provision.yml), we need to somehow wait until the .status.loadBalancer field got populated with the AWS ELB's hostname. How can we achieve this using kubectl wait?
TLDR;
Prior to Kubernetes v1.23 it's not possible using kubectl wait, but using until together with grep like this:
until kubectl get service/tekton-dashboard-external-svc-manual -n tekton-pipelines --output=jsonpath='{.status.loadBalancer}' | grep "ingress"; do : ; done
or even enhance the command using timeout (brew install coreutils on a Mac) to prevent the command from running infinitely:
timeout 10s bash -c 'until kubectl get service/tekton-dashboard-external-svc-manual -n tekton-pipelines --output=jsonpath='{.status.loadBalancer}' | grep "ingress"; do : ; done'
Problem with kubectl wait & the solution explained in detail
As stated in this so Q&A and the kubernetes issues kubectl wait unable to not wait for service ready #80828 & kubectl wait on arbitrary jsonpath #83094 using kubectl wait for this isn't possible in current Kubernetes versions right now.
The main reason is, that kubectl wait assumes that the status field of a Kubernetes resource queried with kubectl get service/xyz --output=yaml contains a conditions list. Which a Service doesn't have. Using jsonpath here would be a solution and will be possible from Kubernetes v1.23 on (see this merged PR). But until this version is broadly available in managed Kubernetes clusters like EKS, we need another solution. And it should also be available as "one-liner" just as a kubectl wait would be.
A good starting point could be this superuser answer about "watching" the output of a command until a particular string is observed and then exit:
until my_cmd | grep "String Im Looking For"; do : ; done
If we use this approach together with a kubectl get we can craft a command which will wait until the field ingress gets populated into the status.loadBalancer field in our Service:
until kubectl get service/tekton-dashboard-external-svc-manual -n tekton-pipelines --output=jsonpath='{.status.loadBalancer}' | grep "ingress"; do : ; done
This will wait until the ingress field got populated and then print out the AWS ELB address (e.g. via using kubectl get service tekton-dashboard-external-svc-manual -n tekton-pipelines --output=jsonpath='{.status.loadBalancer.ingress[0].hostname}' thereafter):
$ until kubectl get service/tekton-dashboard-external-svc-manual -n tekton-pipelines --output=jsonpath='{.status.loadBalancer}' | grep "ingress"; do : ; done
{"ingress":[{"hostname":"a74b078064c7d4ba1b89bf4e92586af0-18561896.eu-central-1.elb.amazonaws.com"}]}
Now we have a one-liner command that behaves just like a kubectl wait for our Service to become available through the AWS Loadbalancer. We can double check if this is working with the following commands combined (be sure to delete the Service using kubectl delete service/tekton-dashboard-external-svc-manual -n tekton-pipelines before you execute it, because otherwise the Service incl. the AWS LoadBalancer already exists):
kubectl apply -f tekton-dashboard-service.yml -n tekton-pipelines && \
until kubectl get service/tekton-dashboard-external-svc-manual -n tekton-pipelines --output=jsonpath='{.status.loadBalancer}' | grep "ingress"; do : ; done && \
kubectl get service tekton-dashboard-external-svc-manual -n tekton-pipelines --output=jsonpath='{.status.loadBalancer.ingress[0].hostname}'
Here's also a full GitHub Actions pipeline run if you're interested.
This question already has answers here:
Run a single kubectl command for a specific project and cluster?
(2 answers)
Closed 2 years ago.
Given a situation where I have three separate GKE instances in different Google Cloud projects under the same billing account, how can I configure kubectl so that the commands I execute with it only apply to a specific cluster?
kubectl access to Kubernetes API servers are managed by configuration contexts.
Here is some documentation for how to do so. In a nutshell, you would stand up multiple Kubernetes clusters and then specify a configuration like so:
apiVersion: v1
kind: Config
preferences: {}
clusters:
- cluster:
name: development
- cluster:
name: scratch
users:
- name: developer
- name: experimenter
contexts:
- context:
name: dev-frontend
- context:
name: dev-storage
- context:
name: exp-scratch
To automatically generate one, you can run the following commands:
# Add cluster details to the file
kubectl config --kubeconfig=config-demo set-cluster development --server=https://1.2.3.4 --certificate-authority=fake-ca-file
kubectl config --kubeconfig=config-demo set-cluster scratch --server=https://5.6.7.8 --insecure-skip-tls-verify
# Add user details to the configuration file
kubectl config --kubeconfig=config-demo set-credentials developer --client-certificate=fake-cert-file --client-key=fake-key-seefile
kubectl config --kubeconfig=config-demo set-credentials experimenter --username=exp --password=some-password
# Add context details to the configuration file
kubectl config --kubeconfig=config-demo set-context dev-frontend --cluster=development --namespace=frontend --user=developer
kubectl config --kubeconfig=config-demo set-context dev-storage --cluster=development --namespace=storage --user=developer
kubectl config --kubeconfig=config-demo set-context exp-scratch --cluster=scratch --namespace=default --user=experimenter
After that, you can safe the context. Then, going forward, when you run a kubectl command, the action will apply to the cluster and namespace listed in the specifeid context. For example:
kubectl config --kubeconfig=config-demo use-context dev-frontend
To then change the context to another one you specified:
kubectl config --kubeconfig=config-demo use-context exp-scratch
I created a Kubernetes cluster using ansible-playbook command below
ansible-playbook kubectl.yaml --extra-vars "kubernetes_api_endpoint=<Path to aws load balancer server>"
Now I have deleted the cluster using command
kubectl config delete-cluster <Name of cluster>
But still EC2 nodes are running, I tried to manually stop them but they start again automatically (expected because they are running in a cluster)
Is there any way by which I can detach the nodes from the cluster or delete the cluster in total?
Kubectl config view shows below message
apiVersion: v1
clusters: []
contexts:
- context:
cluster: ""
user: ""
name: default-context
current-context: default-context
kind: Config
preferences: {}
users:
- name: cc3.k8s.local
user:
token: cc3.k8s.local
This means there is no cluster.
I want to delete the cluster in total and start fresh.
The delete-cluster command does this :
delete-cluster Delete the specified cluster from the kubeconfig
It will only delete the context from your ~/.kube/config file. Not delete the actual cluster.
You will need to write a different script for that or go into the AWS console and simply delete the nodes.
I just ran into this same problem. You need to delete the autoscaling group that spawns the worker nodes, which for some reason isn't deleted when you delete the EKS cluster.
Open the AWS console (console.aws.amazon.com), navigate to the EC2 dashboard, then scroll down the left pane to "Auto Scaling Groups". Deleting the autoscaling group should stop the worker nodes from endlessly spawning. You may also want to click on "Launch Configurations" and delete the template as well.
HTH!
As #Jason mentioned delete-cluster is not an option for you if you want to delete cluster completely.
It would be better if you put ansible playbook file content which creates cluster, then we can see how it creates cluster on AWS.
Best and easiest option for me, you can create also simple playbook file to delete cluster by changing relevant module's state to absent in playbook.
Or if it uses EKS, then you can configure your aws command line then simply run i.e aws eks delete-cluster --name devel. For more info click
If it uses Kops, then you can run kops delete cluster --name <name> --yes
For more info about Kops CMD click
If you still need help, please put ansible playbook file to question by editing.
Trying to update a multi-container pods with
kubectl rolling-update my_rc --image=eu.gcr.io/project_id/myimage
I got:
error: Image update is not supported for multi-container pods
What is the way to update a single container or I must delete and recreate the pod ?
For now, your best option is to update the yaml file defining the replication controller to use the new image and run:
kubectl rolling-update my_rc -f my_file.yaml
If you don't have a yaml file defining your replication controller, you can get one by running:
kubectl get rc my_rc --output=yaml > my_file.yaml
You should then be able to update the image specified in that file and run the rolling-update.
In the next release of Kubernetes (targeted for March), you'll be able to just pass the --container flag to tell kubectl which of the containers in the pod should use the new image:
kubectl rolling-update my_rc --container=my_container --image=eu.gcr.io/project_id/myimage
This feature was added by a community member after version 1.1 was cut.
What I am trying to do:
I have setup kubernete cluster using documentation available on Kubernetes website (http_kubernetes.io/v1.1/docs/getting-started-guides/aws.html). Using kube-up.sh, i was able to bring kubernete cluster up with 1 master and 3 minions (as highlighted in blue rectangle in the diagram below). From the documentation as far as i know we can add minions as and when required, So from my point of view k8s master instance is single point of failure when it comes to high availability.
Kubernetes Master HA on AWS
So I am trying to setup HA k8s master layer with the three master nodes as shown above in the diagram. For accomplishing this I am following kubernetes high availability cluster guide, http_kubernetes.io/v1.1/docs/admin/high-availability.html#establishing-a-redundant-reliable-data-storage-layer
What I have done:
Setup k8s cluster using kube-up.sh and provider aws (master1 and minion1, minion2, and minion3)
Setup two fresh master instance’s (master2 and master3)
I then started configuring etcd cluster on master1, master 2 and master 3 by following below mentioned link:
http_kubernetes.io/v1.1/docs/admin/high-availability.html#establishing-a-redundant-reliable-data-storage-layer
So in short i have copied etcd.yaml from the kubernetes website (http_kubernetes.io/v1.1/docs/admin/high-availability/etcd.yaml) and updated Node_IP, Node_Name and Discovery Token on all the three nodes as shown below.
NODE_NAME NODE_IP DISCOVERY_TOKEN
Master1
172.20.3.150 https_discovery.etcd.io/5d84f4e97f6e47b07bf81be243805bed
Master2
172.20.3.200 https_discovery.etcd.io/5d84f4e97f6e47b07bf81be243805bed
Master3
172.20.3.250 https_discovery.etcd.io/5d84f4e97f6e47b07bf81be243805bed
And on running etcdctl member list on all the three nodes, I am getting:
$ docker exec <container-id> etcdctl member list
ce2a822cea30bfca: name=default peerURLs=http_localhost:2380,http_localhost:7001 clientURLs=http_127.0.0.1:4001
As per documentation we need to keep etcd.yaml in /etc/kubernete/manifest, this directory already contains etcd.manifest and etcd-event.manifest files. For testing I modified etcd.manifest file with etcd parameters.
After making above changes I forcefully terminated docker container, container was existing after few seconds and I was getting below mentioned error on running kubectl get nodes:
error: couldn't read version from server: Get httplocalhost:8080/api: dial tcp 127.0.0.1:8080: connection refused
So please kindly suggest how can I setup k8s master highly available setup on AWS.
To configure an HA master, you should follow the High Availability Kubernetes Cluster document, in particular making sure you have replicated storage across failure domains and a load balancer in front of your replicated apiservers.
Setting up HA controllers for kubernetes is not trivial and I can't provide all the details here but I'll outline what was successful for me.
Use kube-aws to set up a single-controller cluster: https://coreos.com/kubernetes/docs/latest/kubernetes-on-aws.html. This will create CloudFormation stack templates and cloud-config templates that you can use as a starting point.
Go the AWS CloudFormation Management Console, click the "Template" tab and copy out the complete stack configuration. Alternatively, use $ kube-aws up --export to generate the cloudformation stack file.
User the userdata cloud-config templates generated by kube-aws and replace the variables with actual values. This guide will help you determine what those values should be: https://coreos.com/kubernetes/docs/latest/getting-started.html. In my case I ended up with four cloud-configs:
cloud-config-controller-0
cloud-config-controller-1
cloud-config-controller-2
cloud-config-worker
Validate your new cloud-configs here: https://coreos.com/validate/
Insert your cloud-configs into the CloudFormation stack config. First compress and encode your cloud config:
$ gzip -k cloud-config-controller-0
$ cat cloud-config-controller-0.gz | base64 > cloud-config-controller-0.enc
Now copy the content into your encoded cloud-config into the CloudFormation config. Look for the UserData key for the appropriate InstanceController. (I added additional InstanceController objects for the additional controllers.)
Update the stack at the AWS CloudFormation Management Console using your newly created CloudFormation config.
You will also need to generate TLS asssets: https://coreos.com/kubernetes/docs/latest/openssl.html. These assets will have to be compressed and encoded (same gzip and base64 as above), then inserted into your userdata cloud-configs.
When debugging on the server, journalctl is your friend:
$ journalctl -u oem-cloudinit # to debug problems with your cloud-config
$ journalctl -u etcd2
$ journalctl -u kubelet
Hope that helps.
There is also kops project
From the project README:
Operate HA Kubernetes the Kubernetes Way
also:
We like to think of it as kubectl for clusters
Download the latest release, e.g.:
cd ~/opt
wget https://github.com/kubernetes/kops/releases/download/v1.4.1/kops-linux-amd64
mv kops-linux-amd64 kops
chmod +x kops
ln -s ~/opt/kops ~/bin/kops
See kops usage, especially:
kops create cluster
kops update cluster
Assuming you already have s3://my-kops bucket and kops.example.com hosted zone.
Create configuration:
kops create cluster --state=s3://my-kops --cloud=aws \
--name=kops.example.com \
--dns-zone=kops.example.com \
--ssh-public-key=~/.ssh/my_rsa.pub \
--master-size=t2.medium \
--master-zones=eu-west-1a,eu-west-1b,eu-west-1c \
--network-cidr=10.0.0.0/22 \
--node-count=3 \
--node-size=t2.micro \
--zones=eu-west-1a,eu-west-1b,eu-west-1c
Edit configuration:
kops edit cluster --state=s3://my-kops
Export terraform scripts:
kops update cluster --state=s3://my-kops --name=kops.example.com --target=terraform
Apply changes directly:
kops update cluster --state=s3://my-kops --name=kops.example.com --yes
List cluster:
kops get cluster --state s3://my-kops
Delete cluster:
kops delete cluster --state s3://my-kops --name=kops.identityservice.co.uk --yes