Error while applying Node Autoscaler for existing AKS cluster - azure

I am trying to experiment with Preview feature available in Azure AKS as per documentation available we need to have the following requirements
Kubernetes version 1.12.4 or later
Azure CLI version 2.0.55 or later.
add aks preview :- az extension add --name aks-preview
register scale set provider:- az feature register --name VMSSPreview --namespace Microsoft.ContainerService
ensure that it is registerd
created AKS cluster with terraform
when i try to apply following command
az aks update --resource-group rg-euwest-d04-dvag-001 --name k8s-euwest-d04-dvag-dfs-dfsapp-001 --enable-cluster-autoscaler --min-count 3 --max-count 5
error
Operation failed with status: 'Bad Request'. Details: AgentPool
'' has set auto scaling as enabled but is not on Virtual
Machine Scale Sets, this is not allowed

As per my understanding, it is not supported at this time through terraform or from Azure Portal but only possible from Azure CLI

Your cluster needs to be created via Azure CLI to enable autoscaling. So if you have created on evia Azure portal, you need to delete it and create new one through Azure CLI. Ref: https://github.com/MicrosoftDocs/azure-docs/issues/29199

Related

create azure aks with basic load blancer

As I understood from the documentation , if you use azure portal to create AKS cluster , you can't use the basic load balancer ,which is free in my current subscription. So how can I then use the basic load balancer with aks.
You must use the CLI to create an AKS with a Basic load balancer.
az aks create -g MyRG -n MyCluster --load-balancer-sku basic
It's clearly stated in the infobox in the Portal.

How to Simulate Eviction of nodes in Azure Kubernetes

I have spot instance nodes in Azure Kubernetes Cluster. I want to simulate the eviction of a node so as to debug my code but not able to. All I could find in azure docs is we can simulate eviction for a single spot instance, using the following:
az vm simulate-eviction --resource-group test-eastus --name test-vm-26
However, I need to simulate the eviction of a spot node pool or a spot node in an AKS cluster.
For simulating evictions, there is no AKS REST API or Azure CLI command because evictions of the underlying infrastructure is not handled by AKS RP.
Only during creation of the AKS cluster the AKS RP can set eviction Policy on the underlying infrastructure by instructing the Azure Compute RP to do so.
Instead to simulate the eviction of node infrastructure, the customer can use az vmsss simulate-eviction command or the corresponding REST API.
az vmss simulate-eviction
az vmss simulate-eviction --instance-id
--name
--resource-group
[--subscription]
Reference Documents:
https://learn.microsoft.com/en-us/cli/azure/vmss?view=azure-cli-latest#az_vmss_simulate_eviction
https://learn.microsoft.com/en-us/rest/api/compute/virtual-machine-scale-set-vms/simulate-eviction
Use the following commands to get the name of the vmss with nodepool:
1.
az aks nodepool list -g $ClusterRG --cluster-name $ClusterName -o
table
Get the desired node pool name from the output
2.
CLUSTER_RESOURCE_GROUP=$(az aks show –resource-group YOUR_Resource_Group --name YOUR_AKS_Cluster --query
nodeResourceGroup -o tsv)
az vmss list -g $CLUSTER_RESOURCE_GROUP --query "[?tags.poolName == '<NODE_POOL_NAME>'].{VMSS_Name:name}" -o tsv
References:
https://louisshih.gitbooks.io/kubernetes/content/chapter1.html
https://ystatit.medium.com/azure-ssh-into-aks-nodes-471c07ad91ef
https://learn.microsoft.com/en-us/cli/azure/vmss?view=azure-cli-latest#az_vmss_list_instances
(you may create vmss if you dont have it configured. Refer :create a VMSS)

Changing --network-plugin in Azure Kubernetes Service for existing cluster

I'm trying to implement Azure Key Vault such that API keys, credentials and other Kubernetes secrets are read into production and staging environments. Ultimately, I'd like to try to expand that to local development environments so devs don't have to mess with it at all. It is just read in when they start their cluster.
Anyway, I'm following this to enable Pod Identities:
https://learn.microsoft.com/en-us/azure/aks/use-azure-ad-pod-identity
When I get to this step, I'm modifying the:
az aks create -g myResourceGroup -n myAKSCluster --enable-managed-identity --enable-pod-identity --network-plugin azure
To the following because I'm trying to change an existing cluster:
az aks update -g myResourceGroup -n myAKSCluster --enable-managed-identity --enable-pod-identity --network-plugin azure
This doesn't work and figured out I need to run each flag one at a time, so I had to run --enable-managed-identity first since --enable-pod-identity depends on it.
At any rate, when I get to the --enable-pod-identity I get the following error:
Operation failed with status: 'Bad Request'. Details: Network plugin kubenet is not supported to use with PodIdentity addon.
So I try the --network-plugin azure and get:
az: error: unrecognized arguments: --network-plugin azure
Apparently this is flag is not available with update.
Poking around in the Azure portal for the AKS resource, I do see kubenet listed, but I'm not able to change it.
So, the question: Is it possible to change the Network Plugin on existing cluster or do I need to start a new?
EDIT: Looks like others are having similar issues on existing clusters:
https://github.com/Azure/AKS/issues/2094
Is it possible to change the Network Plugin on the existing cluster or do
I need to start a new?
It's impossible to change the network plugin on the existing cluster, so you need to create a new cluster and set the network plugin with azure at the creation time. You can find there is no parameter --network-plugin in the CLI command az aks update even if you install the aks-preview extension. It means it does not support changing the network plugin of the existing cluster.

Where to find Kubernetes API credentials with AKS?

I'm trying to follow this guide to setting up a K8s cluster with external-dns' Azure DNS provider.
The guide states that:
When your Kubernetes cluster is created by ACS, a file named /etc/kubernetes/azure.json is created to store the Azure credentials for API access. Kubernetes uses this file for the Azure cloud provider.
When I create a cluster using aks (e.g. az aks create --resource-group myResourceGroup --name myK8sCluster --node-count 1 --generate-ssh-keys) this file doesn't exist.
Where do the API credentials get stored when using AKS?
Essentially I'm trying to work out where to point this command:
kubectl create secret generic azure-config-file --from-
file=/etc/kubernetes/azure.json
From what I can see when using AKS the /etc/kubernetes/azure.json doesn't get created. As an alternative I followed the instructions for use with non Azure hosted sites and created a service principal (https://github.com/kubernetes-incubator/external-dns/blob/master/docs/tutorials/azure.md#optional-create-service-principal)
Creating the service principal produces some json that contains most of the detail. This can be used to manually create the azure.json file and the secret can be created from it.
Use this command to get credentials:
az aks get-credentials --resource-group myResourceGroup --name myK8sCluster
Source:
https://learn.microsoft.com/en-us/azure/aks/kubernetes-walkthrough
Did you try this command ?
cat ~/.kube/config
It provided all i needed for my CI to connect to the Kubernetes Cluster and use API

Azure Kubernetes on different network?

I've setup kubernetes in azure using the azure acs and the azure cli.
az account list
az account set --subscription foobar
az group create --name foobar --location westus
az acs create --orchestrator-type=kubernetes --resource-group foobar --master-count 1 --name=foobar --dns-prefix=foobar
I want to be able to setup a site to site vpn, so that kubernetes can reach internal services in my datacenter.
Unfortunatly azure acs sets up kubernetes on a 10.0.0.0 network which overlaps with other resources in azure and my datacenter.
I can't find any way to change which subnet kubernetes runs on in acs. Is there a way to change the prefered network?
There does not appear to be a way to choose network from the acs create command
az acs create --name
--resource-group
[--admin-password]
[--admin-username]
[--agent-count]
[--agent-vm-size]
[--client-secret]
[--dns-prefix]
[--generate-ssh-keys]
[--location]
[--master-count]
[--no-wait]
[--orchestrator-type {Custom, DCOS, Kubernetes, Swarm}]
[--service-principal]
[--ssh-key-value]
[--tags]
[--validate]
[--windows]
No, there's no way of doing that. There might be a way to create a new kubernetes to existing vnet, but I'm not aware of that.
Your another option would be to delete all vm's and recreate them in the new vnet. No guarantee it would work.
With ACS through its CLI you can specify subnet id so the acs is created in a particular VNET. However this is only available in certain regions

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