Hi Muthu Kumar T,
Thank you for reaching out to us on Microsoft Q&A forum.
Based on my understanding of the issue, you are practicing the following Learn path exercise.
Subject : Microsoft Certified-Azure Fundamentals
Learning Path : Microsoft Azure Fundamentals: Describe Azure architecture and services.
Module : Describe Azure compute and networking services
Unit 3 of 14 : Exercise - Create an Azure virtual machine.
In Azure, when we create a Linux virtual machine (VM), we typically use SSH key pairs for authentication rather than a password.
In the Exercise - Create an Azure virtual machine under Task 1: Create a Linux virtual machine and install Nginx we have two steps:
Step 1: To create a Linux VM using "az vm create" command and
Step 2: To configure Nginx on the VM created using "az vm extension set" command.
As mentioned in the exercise, we have used generate-ssh-keys for authentication while creating the VM using "az vm create" command rather than a password.
The "az vm extension set" command uses the Custom Script Extension to run a Bash script on your VM to configure Nginx.
We can successfully create a Linux VM and configure Nginx on the VM created by following the above steps of Task 1 and complete the exercise without any password. Kindly find the screenshots attached for reference.
![CS1](https://learn-attachment.microsoft.com/api/attachments/84dd0162-df7f-49c3-be8d-dcd8b3c13946?platform=QnA)
![CS2](https://learn-attachment.microsoft.com/api/attachments/5d68a296-693e-4b35-9112-b80c266671d5?platform=QnA)
We don’t have to manually run the command "sudo apt-get update" separately. The Custom Script Extension used in "az vm extension set" command to run a Bash script takes care of invoking "sudo apt-get update" automatically with elevated permissions. By running the script, the command automatically runs 'sudo apt-get update' with the saved SSH key files.
If we manually run the command "sudo apt-get update"(not required as per the exercise), the system prompts us to enter a password.
![CS3](https://learn-attachment.microsoft.com/api/attachments/5756b1d2-c986-4d79-9eb5-899852574eb0?platform=QnA)
As we have used SSH key pairs for authentication rather than a password, we cannot enter a password.
If we want to connect to the VM created (without a password in this case for Linux VM) we need to do ssh to the vm created, before we can use sudo.
After completing Step 1, create a Linux VM of Task 1, make a note of the publicIpAddress that was assigned to the VM (for example:20.66.97.117).
Connect to the newly created VM using ssh (in cloud shell). We need to substitute the publicIpAddress noted above for <VM public ip address> in the command below:
"ssh azureuser@<VM public ip address>"
Enter 'yes' when you are prompted.
![CS4](https://learn-attachment.microsoft.com/api/attachments/07c36e8f-dc99-40ee-901d-b5e28892e9c9?platform=QnA)
Now we have successfully connected to the VM without using password and we can work in the VM. We can see our VM name as "my-vm" in the screenshot below which is same as given in "az vm create" command.
![CS5](https://learn-attachment.microsoft.com/api/attachments/e9ef80fb-ce7c-40c4-ac12-e5ea5133b3cc?platform=QnA)
If we want to exit from the VM and come into CLI screen we use "exit" command.
![CS6](https://learn-attachment.microsoft.com/api/attachments/19509038-4a19-4bd9-9a02-f9b520581ab3?platform=QnA)
If you are still running into issues,kindly attach the screenshots for reference and please let us know in the comments.We are glad to help you.
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Thank you.