This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(102.4, 52%, 19%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EK%3C/text%3E%3C/svg%3E)
While provisioning the AKS Cluster (Node pool with 3 nodes - autoscale enabled), I am getting this below error. Please suggest potential resolution for the same.
Code="CreateVMSSAgentPoolFailed" Message="Unable to establish outbound connection from agents, please see https://learn.microsoft.com/en-us/troubleshoot/azure/azure-kubernetes/error-code-outboundconnfailvmextensionerror and https://aka.ms/aks-required-ports-and-addresses for more information. Details: Category: ClientError; Code: VMExtensionProvisioningError; SubCode: OutboundConnFailVMExtensionError; Message: Unable to establish outbound connection from agents, please see https://learn.microsoft.com/en-us/troubleshoot/azure/azure-kubernetes/error-code-outboundconnfailvmextensionerror and https://aka.ms/aks-required-ports-and-addresses for more information. Details: instance 0 has extension error details : {vmssCSE error messages : {vmssCSE exit status=50 .......
InnerMessage: ; Dependency: Microsoft.Compute/VirtualMachineScaleSet; AKSTeam: ; Retriable: false"
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(60.8, 4%, 15%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EKM%3C/text%3E%3C/svg%3E)
Hello, @KK1969 !
If an answer has been helpful, please consider accepting the answer to help increase visibility of this question for other members of the Microsoft Q&A community. If not, please let us know what is still needed in the comments so the question can be answered. Thank you for helping to improve Microsoft Q&A!
Hi KK1969,
This issue and its solution is explained here: https://learn.microsoft.com/en-us/troubleshoot/azure/azure-kubernetes/error-code-outboundconnfailvmextensionerror
@mutaz-msft yes. I have already tried and the command "nc -vz mcr.microsoft.com 443" is responding with "TIMEOUT". There is nothing blocking from myend as outbound connectivity is clear. Not sure whether it is something of an issue at other end (mcr.microsoft.com) is causing the failure... Please suggest.
What is the network plugin type?
Do you have any nsg or route table attached to the cluster subnet?
Do you have any VNet peering with the AKS VNet?
Yes. both NSG & Route table are already attached to the Subnet. I got the issue/resolution...
It is about the AKS nodes Subnet which is supposed to be attached to a NAT gateway (which is associated with a Public IP) to have the outbound connectivity. Reference: https://learn.microsoft.com/en-us/azure/aks/egress-outboundtype#outbound-type-of-userdefinedrouting
Thanks for the quick responses.