Connect with SSH to AKS cluster nodes

Question

I am trying to connect with SSH to a scale set-based AKS cluster node for maintenance purposes. I am following the instructions in this article: https://docs.microsoft.com/en-us/azure/aks/ssh

However, when I run: az vmss extension set --name VMAccessForLinux --protected-settings '{\"username\":\"azureuser\", \"ssh_key\":\"$(cat ~/.ssh/id_rsa.pub)\"}' --publisher Microsoft.OSTCExtensions --resource-group $RG_NAME --version 1.4 --vmss-name $NODE_NAME

I get the following error: VM has reported a failure when processing extension 'VMAccessForLinux'. Error message: "Enable failed: Failed to generate public key file. VM has reported a failure when processing extension 'VMAccessForLinux'. Error message: "Enable failed: Failed to generate public key file.

My SSH key pair is located at C:\Users\username\.ssh and readable. I have tried generating multiple pairs, but the issue does not seem to be here. For generating the keys I used: ssh-keygen -m PEM -t rsa -b 4096

Any idea where I can find more information about this error or how can I troubleshoot it in more detail? Thank you.

Answer 1

The reason is that you need to use the double quotes to set the value of the parameter `--protected-setting like this:

--protected-settings "{\"username\":\"azureuser\", \"ssh_key\":\"$(cat ~/.ssh/id_rsa.pub)\"}"

Only when you use the double quotes then the character \ can work. You need to read the document carefully. And make sure the SSH public key is in the right format.