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Repair a Linux VM by using the Azure Virtual Machine repair commands

  • Článek

Applies to: ✔️ Linux VMs

If your Linux virtual machine (VM) in Azure encounters a boot or disk error, you may need to perform mitigation on the disk itself. A common example would be a failed application update that prevents the VM from being able to boot successfully. This article details how to use Azure Virtual Machine repair commands to connect the disk to another Linux VM to fix any errors, then rebuild your original VM.

Important

  • The scripts in this article only apply to the VMs that use Azure Resource Manager.
  • Outbound connectivity from the VM (port 443) is required for the script to run.
  • Only one script may run at a time.
  • A running script cannot be canceled.
  • The maximum time a script can run is 90 minutes, after which it will time out.
  • Do not modify the tags that are created on the repair VM. The tags are neccessary for the restore command to function correctly.
  • For VMs using Azure Disk Encryption, only managed disks encrypted with single pass encryption (with or without KEK) are supported.

Repair process overview

You can now use Azure Virtual Machine repair commands to change the OS disk for a VM, and you no longer need to delete and recreate the VM.

Follow these steps to troubleshoot the VM issue:

  1. Launch Azure Cloud Shell
  2. Run az extension add/update
  3. Run az vm repair create
  4. Run az vm repair run, or perform mitigation steps.
  5. Run az vm repair restore

To view all available VM repair commands and parameters, see az vm repair.

To run the commands, you need a role that can create the following types of resources in the subscription:

  • Resource Groups
  • Virtual Machines
  • Resource Tags
  • Virtual Networks
  • Network Security Groups
  • Network Interfaces
  • Disks
  • Public IP Addresses (Optional)

Repair process example

  1. Launch Azure Cloud Shell

    The Azure Cloud Shell is a free interactive shell that you can use to run the steps in this article. It includes common Azure tools preinstalled and configured to use with your account. If you run a repair script that will take longer than 20 minutes, you may prefer to run the commands locally. To run the commands locally, Azure CLI version 2.0.67 or later version is required. Run az --version to find the version. If you need to install or upgrade your Azure CLI, see Install Azure CLI.

    To open the Cloud Shell, select Try it from the upper-right corner of a code block. You can also open Cloud Shell in a separate browser tab by going to https://shell.azure.com.

    Select Copy to copy the blocks of code, then paste the code into the Cloud Shell, and select Enter to run it.

    If you prefer to install and use the CLI locally, this quickstart requires Azure CLI version 2.0.67 or later. Run az --version to find the version. If you need to install or upgrade your Azure CLI, see Install Azure CLI.

    If you need to login to Cloud Shell with a different account than you are currently logged in to the Azure portal with you can use az login az login reference. To switch between subscriptions associated with your account you can use az account set --subscription az account set reference.

  2. If this is the first time you have used the az vm repair commands, add the vm-repair CLI extension.

    az extension add -n vm-repair

    If you have previously used the az vm repair commands, apply any updates to the vm-repair extension.

    az extension update -n vm-repair

  3. Run az vm repair create. This command will create a copy of the OS disk for the non-functional VM, create a repair VM in a new Resource Group, and attach the copy of the OS disk. The repair VM will be the same size and region as the non-functional VM specified. The Resource Group and VM name used in all steps will be for the non-functional VM. If your VM is using Azure Disk Encryption, use --unlock-encrypted-vm to unlock the encrypted disk so that it is accessible when attached to the repair VM. For more information, see confirm that ADE is enabled on the disk.

Important

The run and restore commands will require all inputs to be entered using the same case as used in the create command, make note or refer to the tags on the repair VM to see what was used.

Repair VM example

az vm repair create -g MyResourceGroup -n myVM --repair-username username --repair-password password1234 --verbose

  1. Run az vm repair run. This command will run the specified repair script on the attached disk via the repair VM. If the troubleshooting guide you are using specified a run-id, use it here. Otherwise, you can use az vm repair list-scripts to see available repair scripts. The Resource Group and VM name used here are for the non-functional VM used in step 3. Additional information about the repair scripts can be found in the repair script library.

    az vm repair run -g MyResourceGroup -n MyVM --run-on-repair --run-id lin-hello-world --verbose

    Optionally you can perform any needed manual mitigation steps using the repair VM, then proceed to step 5.

  2. Run az vm repair restore. This command will swap the repaired OS disk with the original OS disk of the VM. The Resource Group and VM name used here are for the non-functional VM used in step 3.

    az vm repair restore -g MyResourceGroup -n MyVM --verbose

Verify and enable boot diagnostics

The following example enables the diagnostic extension on the VM named myVMDeployed in the resource group named myResourceGroup:

Azure CLI

az vm boot-diagnostics enable --name myVMDeployed --resource-group myResourceGroup --storage https://mystor.blob.core.windows.net/

Next steps

Contact us for help

If you have questions or need help, create a support request, or ask Azure community support. You can also submit product feedback to Azure feedback community.