Cannot migrate a .NET IIS web application with Azure Migrate

Question

Cannot migrate a .NET IIS web application with Azure Migrate

Anders Hermann Pedersen 0

I'm using Azure Migrate to discover, assess and migrate a number of applications from a VSphere based on-prem datacenter to Azure. For web applications, I would like to migrate them to Azure App Services where possible.

I'm trying to do a replication to prepare for migration, selecting ASP.NET web apps to migrate, Azure App Service code to migrate to and VMWare vSphere as virtualization type. However, the dropdown for "select assessment" is empty, even though I have previously completed an assessment. What could the reason be for this? I have full read/write access to assessments, so I don't think access rights are the issue.

Any help is much appreciated

Ashok Gandhi Kotnana 6,680 Reputation points Microsoft External Staff Moderator

2025-04-08T11:46:50.96+00:00

Hi @Anders Hermann Pedersen

Kindly complete the assessment under the WebApps tab by following the outlined process. don't do it from the assessment from the Servers tab. Let me know how it goes

Refer below article: -

https://learn.microsoft.com/en-us/azure/app-service/app-service-asp-net-migration#app-service-migration-tools-and-resources

Thankyou
Ashok Gandhi Kotnana 6,680 Reputation points Microsoft External Staff Moderator

2025-04-09T07:16:01.3+00:00

Hi @Anders Hermann Pedersen

Just want to check if the above answer worked for you or else please let us know if any help, we are always here to help whenever you need us.

If the comment is helpful, please click "Upvote it".
Anders Hermann Pedersen 0 Reputation points

2025-04-09T08:06:09.0833333+00:00

Hello @Ashok Gandhi Kotnana

Thank you for the suggestion and feedback. As the suggested workaround requires some extra work with the migration assistant tool as well as opening firewalls, it has not been completed yet, but I will try it out.

However, I'm not really convinced that this is going to be a viable solution. While this method allows a per-application migration, I'm really looking to do this at scale as described here: https://learn.microsoft.com/en-us/azure/migrate/tutorial-modernize-asp-net-appservice-code

This refers to web app assessment as described here: https://learn.microsoft.com/en-us/azure/migrate/tutorial-assess-webapps?pivots=asp-net

Best regards

Anders
Ashok Gandhi Kotnana 6,680 Reputation points Microsoft External Staff Moderator

2025-04-09T11:40:50.9766667+00:00

Hi @Anders Hermann Pedersen

Please try it out and let me know how it goes, also let me check the other options from my end.

Thankyou
Ashok Gandhi Kotnana 6,680 Reputation points Microsoft External Staff Moderator

2025-04-10T14:42:49.1533333+00:00

Hi @Anders Hermann Pedersen ,

Just wanted to check if you have tried the option assessment under the WebApps tab

Thankyou
Anders Hermann Pedersen 0 Reputation points

2025-04-11T05:02:13.5333333+00:00

Hello @Ashok Gandhi Kotnana

We're trying the solution, but its leading us to some other difficulties. While we can indeed do the assessment with the migration assessment tool, we're currently getting an error when sending the assessment data to Azure

"Step error details: Error: RegisterTool error: Error: Operation is blocked for the solution"

We're trying to dig into why this is happening.

Best regards

Anders
Vinod Pittala 1,830 Reputation points Microsoft External Staff Moderator

2025-04-11T08:26:27.2366667+00:00

Hello Anders Hermann Pedersen,

To do the assessment for any on-prem server or Web app or databases, first we need to discover it successfully. once the web app discovered it can be visible in the assessment page. You can then assess those web apps are capable enough to migrate to azure or not?

So, kindly confirm if you had discovered the web app already using Discover option. If not, kindly proceed with the discovery first.

If the provided solution works for your query, please do not forget to click Upvote Button. this can be beneficial to other community members.it would be greatly appreciated and helpful to others

Thanks
Anders Hermann Pedersen 0 Reputation points

2025-04-11T09:00:06.4533333+00:00

Thanks for the feedback @Vinod Pittala

Yes, we've done a complete agentless discovery using an appliance in an on-prem vSphere environment. From the resulting discovered web apps, we've done assessments consisting of applications that are "ready", "ready with conditions" as well as "not ready" for migration.

From this assessment, we would like to do a replication as the first step in migration, but that is not possible as we cannot select any assessments as indicated in my original post.

The suggestion is to try with a single web app using the web app migration tool, but that is also causing some issues as indicated in my previous post. We're not entirely sure what is causing it to fail, and the reported error is quite limited.

Best regards

Anders
Vinod Pittala 1,830 Reputation points Microsoft External Staff Moderator

2025-04-11T09:18:53.69+00:00
Hello Anders Hermann Pedersen,

I understand that you have previously completed the assessment, but it is now failing upon retrying.

There could be various reasons for this issue. One possibility is that changes to on-premises web app instances within an assessed group can mark the assessment as outdated. However, the synchronization between the on-premises environment and the Azure Migrate assessment service occurs only every 24 hours. To manually trigger a refresh, please follow the steps below:

Troubleshooting Steps:

Go to azure portal and open your Azure Migrate project.

Click on Appliances and select your appliance.

Check the connection status of the Web App discovery and assessment agent.

If the agent is connected, perform a manual refresh to pull the latest updates from the on-premises environment. Wait for an hour for the updates to reflect in the portal.

Afterward, try to perform the assessment again.

If the provided solution works for your query, please do not forget to click Upvote Button. this can be beneficial to other community members.it would be greatly appreciated and helpful to others

Thanks
Anders Hermann Pedersen 0 Reputation points

2025-04-11T09:45:31.0233333+00:00

Hi @Vinod Pittala

No thats not exactly the case here. The assessment is working fine - both assessments from the "Servers, databases and web apps" tab, but also from the "Web apps" tab, using the web app migration tool. However, in the latter solution it fails when uploading the assessment result to the migrate project, with the error I previously posted: "Step error details: Error: RegisterTool error: Error: Operation is blocked for the solution"

Best regards

Anders

1 answer

Your answer

Ashok Gandhi Kotnana 6,680 Reputation points Microsoft External Staff Moderator

2025-04-08T11:46:50.96+00:00

Hi @Anders Hermann Pedersen

Kindly complete the assessment under the WebApps tab by following the outlined process. don't do it from the assessment from the Servers tab. Let me know how it goes

Refer below article: -

https://learn.microsoft.com/en-us/azure/app-service/app-service-asp-net-migration#app-service-migration-tools-and-resources

Thankyou
Ashok Gandhi Kotnana 6,680 Reputation points Microsoft External Staff Moderator

2025-04-09T07:16:01.3+00:00

Hi @Anders Hermann Pedersen

Just want to check if the above answer worked for you or else please let us know if any help, we are always here to help whenever you need us.

If the comment is helpful, please click "Upvote it".
Anders Hermann Pedersen 0 Reputation points

2025-04-09T08:06:09.0833333+00:00

Hello @Ashok Gandhi Kotnana

Thank you for the suggestion and feedback. As the suggested workaround requires some extra work with the migration assistant tool as well as opening firewalls, it has not been completed yet, but I will try it out.

However, I'm not really convinced that this is going to be a viable solution. While this method allows a per-application migration, I'm really looking to do this at scale as described here: https://learn.microsoft.com/en-us/azure/migrate/tutorial-modernize-asp-net-appservice-code

This refers to web app assessment as described here: https://learn.microsoft.com/en-us/azure/migrate/tutorial-assess-webapps?pivots=asp-net

Best regards

Anders
Ashok Gandhi Kotnana 6,680 Reputation points Microsoft External Staff Moderator

2025-04-09T11:40:50.9766667+00:00

Hi @Anders Hermann Pedersen

Please try it out and let me know how it goes, also let me check the other options from my end.

Thankyou
Ashok Gandhi Kotnana 6,680 Reputation points Microsoft External Staff Moderator

2025-04-10T14:42:49.1533333+00:00

Hi @Anders Hermann Pedersen ,

Just wanted to check if you have tried the option assessment under the WebApps tab

Thankyou
Anders Hermann Pedersen 0 Reputation points

2025-04-11T05:02:13.5333333+00:00

Hello @Ashok Gandhi Kotnana

We're trying the solution, but its leading us to some other difficulties. While we can indeed do the assessment with the migration assessment tool, we're currently getting an error when sending the assessment data to Azure

"Step error details: Error: RegisterTool error: Error: Operation is blocked for the solution"

We're trying to dig into why this is happening.

Best regards

Anders
Vinod Pittala 1,830 Reputation points Microsoft External Staff Moderator

2025-04-11T08:26:27.2366667+00:00

Hello Anders Hermann Pedersen,

To do the assessment for any on-prem server or Web app or databases, first we need to discover it successfully. once the web app discovered it can be visible in the assessment page. You can then assess those web apps are capable enough to migrate to azure or not?

So, kindly confirm if you had discovered the web app already using Discover option. If not, kindly proceed with the discovery first.

If the provided solution works for your query, please do not forget to click Upvote Button. this can be beneficial to other community members.it would be greatly appreciated and helpful to others

Thanks
Anders Hermann Pedersen 0 Reputation points

2025-04-11T09:00:06.4533333+00:00

Thanks for the feedback @Vinod Pittala

Yes, we've done a complete agentless discovery using an appliance in an on-prem vSphere environment. From the resulting discovered web apps, we've done assessments consisting of applications that are "ready", "ready with conditions" as well as "not ready" for migration.

From this assessment, we would like to do a replication as the first step in migration, but that is not possible as we cannot select any assessments as indicated in my original post.

The suggestion is to try with a single web app using the web app migration tool, but that is also causing some issues as indicated in my previous post. We're not entirely sure what is causing it to fail, and the reported error is quite limited.

Best regards

Anders
Vinod Pittala 1,830 Reputation points Microsoft External Staff Moderator

2025-04-11T09:18:53.69+00:00

Hello Anders Hermann Pedersen,

I understand that you have previously completed the assessment, but it is now failing upon retrying.

There could be various reasons for this issue. One possibility is that changes to on-premises web app instances within an assessed group can mark the assessment as outdated. However, the synchronization between the on-premises environment and the Azure Migrate assessment service occurs only every 24 hours. To manually trigger a refresh, please follow the steps below:

Troubleshooting Steps:

Go to azure portal and open your Azure Migrate project.

Click on Appliances and select your appliance.

Check the connection status of the Web App discovery and assessment agent.

If the agent is connected, perform a manual refresh to pull the latest updates from the on-premises environment. Wait for an hour for the updates to reflect in the portal.

Afterward, try to perform the assessment again.

If the provided solution works for your query, please do not forget to click Upvote Button. this can be beneficial to other community members.it would be greatly appreciated and helpful to others

Thanks
Anders Hermann Pedersen 0 Reputation points

2025-04-11T09:45:31.0233333+00:00

Hi @Vinod Pittala

No thats not exactly the case here. The assessment is working fine - both assessments from the "Servers, databases and web apps" tab, but also from the "Web apps" tab, using the web app migration tool. However, in the latter solution it fails when uploading the assessment result to the migrate project, with the error I previously posted: "Step error details: Error: RegisterTool error: Error: Operation is blocked for the solution"

Best regards

Anders

Answer 1

Ashok Gandhi Kotnana 6,680 Microsoft External Staff Moderator

Hi @Anders Hermann Pedersen ,

Thanks for your time on the call!

As discussed during our call, the issue is related to the assessment report being in a "Ready with Conditions" or "Outdated" state.

Please perform the following steps on the server that is in a fully "Ready" state (i.e., without any conditions):

Restart the DRA Agent and Gateway Service.

Once the services have been restarted, restart the server.

Wait for 15 minute to allow the changes to reflect and ensure that the services are up and running.

If the issue persists after these steps, we will need to redeploy the OVA and re-run the assessment as discussed.

https://learn.microsoft.com/en-us/azure/migrate/migrate-appliance#appliance-services

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Please do not forget to "Accept the answer” and “upvote it” wherever the information provided helps you, this can be beneficial to other community members.it would be greatly appreciated and helpful to others.

Ashok Gandhi Kotnana 6,680 Reputation points Microsoft External Staff Moderator

2025-04-14T02:54:11.3566667+00:00

Hi @Anders Hermann Pedersen ,

Just want to check if the above answer worked for you or else please let us know if any help, we are always here to help whenever you need us.

Please do not forget to "Accept the answer” and “upvote it” wherever the information provided helps you, this can be beneficial to other community members.it would be greatly appreciated and helpful to others.
Anders Hermann Pedersen 0 Reputation points

2025-04-22T11:01:09.9966667+00:00

Hi @Ashok Gandhi Kotnana

Thank you for the suggestions! We've now managed to try it out, but without success. We are still getting the exact same results, where the assessment drop down is empty, even though there are Ready assessments that should be shown.

Is there anything else we can try? As far as I can tell from the documentation, only port 443 needs to be open for VMWare, do you know if thats accurate?

Best regards

Anders
Ashok Gandhi Kotnana 6,680 Reputation points Microsoft External Staff Moderator

2025-04-22T20:08:16.22+00:00

Hi @Anders Hermann Pedersen ,

Please refer to the below article and let me know how it goes, the article has the similar issue which you are referring to

https://learn.microsoft.com/en-us/azure/migrate/common-questions-discovery-assessment#i-cant-see-some-servers-when-im-creating-an-azure-app-service-assessment

Let me know how it goes.

Thankyou

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Cannot migrate a .NET IIS web application with Azure Migrate

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Your answer