I'm beginning to build out a kubernetes cluster for our applications. We are using Azure for cloud services, so my K8s cluster is built using AKS. The AKs cluster was created using the portal interface for Azure. It has one node, and I am attempting to create a pod with a single container to deploy to the node. Where I am stuck currently is trying to connect to the AKS cluster from Powershell.
The steps I have taken are:
az login (followed by logging in)
az account set --subscription <subscription id>
az aks get-credentials --name <cluster name> --resource-group <resource group name>
kubectl get nodes
After entering the last line, I am left with the error: Unable to connect to the server: dial tcp: lookup : no such host
I've also gone down a few other rabbit holes found on SO and other forums, but quite honestly, I'm looking for a straight forward way to access my cluster before complicating it further.
Edit: So in the end, I deleted the resource I was working with and spun up a new version of AKS, and am now having no trouble connecting. Thanks for the suggestions though!
As of now, the aks run command adds a fourth option to connect to private clusters extending #Darius's three options posted earlier:
Use the AKS Run Command feature.
Below are some copy/paste excerpts of a simple command, and one that requires a file. It is possible to chain multiple commands with &&.
az aks command invoke \
--resource-group myResourceGroup \
--name myAKSCluster \
--command "kubectl get pods -n kube-system"
az aks command invoke \
--resource-group myResourceGroup \
--name myAKSCluster \
--command "kubectl apply -f deployment.yaml -n default" \
--file deployment.yaml
In case you get a (ResourceGroupNotFound) error, try adding the subscription, too
az aks command invoke \
--resource-group myResourceGroup \
--name myAKSCluster \
--subscription <subscription> \
--command "kubectl get pods -n kube-system"
You can also configure the default subscription:
az account set -s <subscription>
Unable to connect to the server: dial tcp: lookup : no such host
The error is coming because of private cluster. The Private Cluster option is enabled while creating the AKS cluster. You need to disable this option.
Kubectl is a kubernetes control client. It is an external connectivity provider to connect with our kubernetes cluster. We can't connect with the private cluster externally.
Believe me.... just disable the private cluster options And see your success. Thank you.
Note: We can't disable this option after the cluster creation. you need to delete the cluster and again reform it.
Posting this as Community Wiki for better visibility.
Solution provided by OP:
Delete resource and spun up a new version of AKS.
For details, you can check docs Create a resource group, Create AKS cluster and resource create.
Next try worth to try:
kubectl config use-context <cluster-name>
as it was proposed in similar Github issue.
Gaurav's answer pretty much sums it up. In fact you can refer to the documentation which states that
The API server endpoint has no public IP address. To manage the API
server, you'll need to use a VM that has access to the AKS cluster's
Azure Virtual Network (VNet). There are several options for
establishing network connectivity to the private cluster.
To connect to a private cluster, there are only 3 methods:
Create a VM in the same Azure Virtual Network (VNet) as the AKS cluster.
Use a VM in a separate network and set up Virtual network peering. See the section below for more information on this option.
Use an Express Route or VPN connection.
It is more convenient to use Az module from desktop Powershell for any management operation with Azure portal. Microsoft adds a lot of new cmdlets for managing AKS and Service Fabric clusters.
Please take a look Az.Aks
In your case:
Connect-AzAccount
Get-AzAksNodePool
I was also facing the issue, I'm using a private cluster and I have a machine (bastion) in a different vnet with peering enabled but still, I was not able to connect the cluster (I was able to SSH and telnet to the machine).
Then I added a virtual network link in the private DNS zone for the vnet where the bastion host resides. It worked for me, I'm able to access the cluster.
When using a private cluster, the kubernetes api-endpoint is only accessible on the cluster's VNet. Connecting via VPN unfortunately does not work painlessly since the azure private DNS will not be available via for VPN clients (yet).
However, it is possible to connect kubectl directly to the IP-address of the api-endpoint, but that will require you to ignore certificate errors since we are using the IP directly.
If you edit your .kube/config and change the server address to the IP number. Then call kubectl with something like this
kubectl get all --all-namespaces --insecure-skip-tls-verify
Usually, this is all that is required to connect. Check whether firewall is not blocking any traffic. Also, verify subscription id and other identifiers again and make sure you are using the correct values. If the issue still persists, I recommend you ask azure support to help you out.
I had the same issues when running the kubectl command from jenkins. For me it was the permission issues of ~/.kube/config I gave it access to jenkins as well which solved the issue for me.
You can run kubectl commands on a private AKS cluster using az aks command invoke. Refer to this for more info.
As for why you might want to run private AKS clusters, read this
You can simply append "--admin" to the query as seen below.
az aks get-credentials --name <cluster name> --resource-group <resource group name> --admin
I also hit this after restarting my kubernetes cluster, but it turned out I was just not waiting long enough, after about 10 minutes the "kubectrl" commands started working again.
If you are using AWS with kops then this might help you
mkdir autoscaler
cd autoscaler/
git clone https://github.com/kubernetes/autoscaler.git
create a file called ig-policy.json with the contents
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"autoscaling:DescribeAutoScalingGroups",
"autoscaling:DescribeAutoScalingInstances",
"autoscaling:DescribeLaunchConfigurations",
"autoscaling:SetDesiredCapacity",
"autoscaling:TerminateInstanceInAutoScalingGroup"
],
"Resource": "*"
}
]
}
Then you need to create iam policy
aws iam create-policy --policy-name ig-policy --policy-document file://ig-policy.json
And attach the above create iam policy with the user id to the cluster name
aws iam attach-role-policy --policy-arn arn:aws:iam::005935423478650:policy/ig-policy --role-name nodes.testing.k8s.local
Then update the cluster
kops update cluster testing.k8s.local --yes
Then run
kops rolling-update cluster
Creating private not easy journey, but it has beautiful views so I encourage anyone to get there.
I did it all in terraform, so some names can be little different than they are in portal/azure CLI.
And this is how I did it:
Private DNS zone, with name as privatelink.westeurope.azmk8s.io
VNET where AKS will be placed (let's call it vnet-access)
Virtual network from which you want to access AKS
Private AKS (private_dns_zone_id set to dns zone form first point)
Virtual network link (in private DNS zone, pointing to VNET from point 3)
Peering between networks from points 2 and 3.
This should allow any machine in vnet-access to firstly resolve DNS, and then - to access cluster...
Yet... if you want to get there from your local machine, this is another setup. Fortunately Microsoft have such tutorial here
If you find that something is still not working - put the error in comment and I'll try to adapt my answer to cover this.
For me I had this issue when I was trying to connect a new Linux user to my Elastic Kubernetes Cluster in AWS.
I setup a new user called jenkins-user, then I tried to run the command below to get pods:
kubectl get pods
And then I will run into the error below:
Unable to connect to the server: dial tcp: lookup 23343445ADFEHGROGMFDFMG.sk1.eu-east-2.eks.amazonaws.com on 198.74.83.506:53: no such host
Here's how I solved it:
The issue was because I had not set the context for the Kubernetes cluster in the kube config file of the new linux user (jenkins-user).
All I had to do was either first install the aws-cli for this new user (install it into the home directory of this new user). And then run the command aws configure to configure the necessary credentials. Although, since I already had the aws-cli setup for the other users on the Linux system I simply copied the ~/.aws directory from an already existing user to the jenkins-user home directory using the command:
sudo cp -R /home/existing-user/.aws/ /home/jenkins-user/
Next, I had to create a context for the Kubernetes configuration which will create a new ~/.kube/config file for the jenkins-user using the command below:
aws eks --region my-aws-region update-kubeconfig --name my-cluster-name
Next, I checked the kube config file to confirm that my context has been added using the command:
sudo nano /.kube/config
This time when I ran the command below, it was successful:
kubectl get pods
Resources: Create a kubeconfig for Amazon EKS
I faced the same issue and resolved it by deleting .kube folder which was under the following path C:\Users\<your_username> and then restarting kubernetes cluster.
I'm creating an App Service with containers in Azure but in logs I found out that when docker run command is executed, always takes port 80 for starting application, however my application in container is listening on port 5000. How I can change it in order to take port 5000 insted of 80 when it execute docker run command?
Had the same issue, you can either use Azure CLI to set:
az webapp config appsettings set --resource-group <resource-group-name> --name <app-name> --settings WEBSITES_PORT=5000
Or add directly from Azure Portal:
Hope if helps.
I have a cluster configured on azure kubernetes . and the services are working fine.
following this article
https://learn.microsoft.com/en-us/azure/aks/kubernetes-dashboard
i am trying to view dashboard using but get the error as follows
az aks browse --resource-group DemoRG--name aksdemo2
Proxy running on http://127.0.0.1:8001/
Press CTRL+C to close the tunnel...
Error: unknown flag: --address
My cluster does not have RBAC enabled , i am unsure if this is related to network issue or something different.
Eventaully issue was resolved by author of this post by following existing github issue #8642:
I had two copies of kubectl and the one from docker was overriding the
one from azure. Found this by firing "where kubectl" from command
prompt, and deleting the docker copy.
Just run kubectl proxy then go to following URL
http://localhost:8001/api/v1/namespaces/kube-system/services/kubernetes-dashboard/proxy/#!/overview?namespace=default
I used kubectl proxy to access the dashboard
I add bitnami.bitnami/rabbitmq into my acr.
In VSO release pipeline, I add 2 tasks kubectl run & expose, looks like below.
kubectl run rabbitmq --image xxxxxx.azurecr.io/bitnami.bitnami/rabbitmq:3.7.7 --port=15672
kubectl expose deployment rabbitmq --type=LoadBalancer --port=15672 --target-port=15672
After save and release it, everything is successful, but now I can't proxy into my dashboard using
az aks browse -g {groupname} -n {k8sname}
When I remove the above 2 task in my release, I able to connect to my dashboard.
Can someone explain to me what going wrong, how to troubleshoot it.
You can check if the pods work well in your Azure Kubernetes Cluster. If everything is OK. Then you should make sure that if your current OS has the browser. The command az aks browse -g {groupname} -n {k8sname} need a browser to open the dashboard where it executes.
You can open the k8s dashboard in another OS with the command you posted after you get the credential with the command az aks get-credentials -g {groupname} -n {k8sname}. Of curse, you need to execute az login first.
If things above all are OK, you could try this link.
I have deployed a NodeJS application to Linux App Service that logs to stderr and stdout. The diagnostic logs functionality in Linux App Service does not appear to work, as nothing appears in table storage. The only logs in Kudu are from when the docker container is deployed. After that, it logs nothing.
The SSH component in Kudu does not work, even after following the official setup documentation.
Has anyone come up with a way to capture stdout and stderr? or can recommend a library that they have gotten to work successfully with NodeJS on the Linux App Service platform?
You could use Azure CLI 2.0 to capture stdout. Try to use the following commands.
az webapp log config -g <resource group name> -n <app name> --application-logging true --detailed-error-messages true --level verbose
az webapp log tail -g <resource group name> -n <app name>
You could get help with -h
root#shui:~# az webapp log config -h
Command
az webapp log config: Configure web app logs.
Arguments
--application-logging : Configure application logging to file system. Allowed values: false,
true.
--detailed-error-messages: Configure detailed error messages. Allowed values: false, true.
--failed-request-tracing : Configure failed request tracing. Allowed values: false, true.
--level : Logging level. Allowed values: error, information, verbose, warning.
--slot -s : The name of the slot. Default to the productions slot if not
specified.
--web-server-logging : Configure Web server logging. Allowed values: filesystem, off,
storage.
More information about Azure Cli supports linux webapp please refer to this link.