Azure temporary disk not present for instance type

Bug #1901011 reported by Terry Cain on 2020-10-22
This bug affects 2 people
Affects Status Importance Assigned to Milestone
Johnson Shi

Bug Description

Cloud Provider: Azure
Instance type: Dsv4

The new Dv4, Dsv4, Ev4, and Esv4 instance types don't come with a temporary disk at /dev/disk/cloud/azure_resource

So when I create/reboot one of these new instances I get longer reboot times as cloud-init is waiting 2 minutes for this disk path to appear.
Looks like the function that looks for the disk is here -

Log snippet:
2020-10-21 12:34:43,120 -[DEBUG]: start: init-network/activate-datasource: activating datasource
2020-10-21 12:34:43,120 -[DEBUG]: start: azure-ds/activate: activate
2020-10-21 12:34:43,120 -[DEBUG]: start: azure-ds/address_ephemeral_resize: address_ephemeral_resize
2020-10-21 12:34:43,120 -[DEBUG]: start: azure-ds/wait-for-ephemeral-disk: wait for ephemeral disk
2020-10-21 12:34:43,121 -[DEBUG]: Azure ephemeral disk: Waiting up to 120 seconds for the following files: ['/dev/disk/cloud/azure_resource']
2020-10-21 12:36:43,160 -[DEBUG]: Azure ephemeral disk: Still missing files after 120 seconds: {'/dev/disk/cloud/azure_resource'}
2020-10-21 12:36:43,161 -[WARNING]: ephemeral device '/dev/disk/cloud/azure_resource' did not appear after 120 seconds.
2020-10-21 12:36:43,161 -[DEBUG]: finish: azure-ds/wait-for-ephemeral-disk: SUCCESS: wait for ephemeral disk
2020-10-21 12:36:43,161 -[DEBUG]: finish: azure-ds/address_ephemeral_resize: SUCCESS: address_ephemeral_resize

I've looked in the instance metadata between a Dsv4 and Dsv3 and there is nothing to indicate if this temporary disk will be present.

More than happy to make a patch to look for the instance type and skip the call if its not needed.

Additional info:

Azure temporary disk VM list -

Chris Pressland (cpressland) wrote :

How's that for timing, I was literally going to raise this today. +1 and all that.

Johnson Shi (johnsonshi) wrote :

We're (MSFT) taking a look at this right now and seeing if anything can be done.

James Falcon (falcojr) on 2020-10-28
Changed in cloud-init:
status: New → Triaged
importance: Undecided → Medium
assignee: nobody → Johnson Shi (johnsonshi)
Johnson Shi (johnsonshi) wrote :

WIP PR addressing this issue at

Changed in cloud-init:
milestone: none → 21.1
Eduardo Otubo (otubo) wrote :

This bug is believed to be fixed in cloud-init in version 21.1. If this is still a problem for you, please make a comment and set the state back to New

Thank you.

Changed in cloud-init:
status: Triaged → Fix Released
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