Cannut Update my cloud service (extended support) site

Question

Cannut Update my cloud service (extended support) site

Rich Simpson 20

Failed to update the deployment for cloud service 'c4c'. Reason: Allocation failed. The cluster where the Cloud Service is allocated may be out of capacity. Site is up and running, has been for years, normally gets updated 3-6 times a year, now all of a sudden it fails and I get this message.

Sujitha Lakkireddy 85 Reputation points Microsoft External Staff Moderator

2026-07-25T10:55:35.0033333+00:00
Hello Rich Simpson,

Thank you for choosing Microsoft Q&A forum.

Thanks for sharing the details. This appears to be an allocation failure in Azure Cloud Services (extended support), not a container-related issue. The key message is:

"Allocation failed. The cluster where the Cloud Service is allocated may be out of capacity.”

In Azure Cloud Services, when the first instance is deployed, the cloud service can be pinned to a cluster, and later deployments or scale operations are attempted in the same cluster. If that cluster has limited capacity, or does not support the requested VM size, the update can fail even though the existing site is still running.

As initial troubleshooting, please check:

Azure Activity Log for the failed Cloud Service update operation.

The detailed AllocationFailed / OverconstrainedAllocationRequest message.

VM size/SKU availability in the target region.

Azure Service Health for any regional platform or capacity issues.

Whether scaling, VIP swap, or swappable cloud services are involved.

If retrying later does not help, one recovery option is to redeploy the same workload to a new Cloud Service (extended support), validate it, and then update the DNS CNAME or A record to route traffic to the new service. With proper planning, this can help minimize downtime.

If VIP swap or swappable cloud services are involved, please note that swappable services may be allocated to the same cluster. If that cluster is constrained, the paired deployment may also fail, and recovery may require recreating the swappable services, which can involve downtime.

References:
https://learn.microsoft.com/en-gb/troubleshoot/azure/cloud-services/extended/availability/allocation-failure
https://learn.microsoft.com/en-gb/azure/cloud-services-extended-support/faq#what-resources-linked-to-a-cloud-services-extended-support-deployment-need-to-live-in-the-same-region
Rich Simpson 20 Reputation points

2026-07-25T11:06:09.61+00:00
Yes I have read and check all that applies (most of the troubleshooting steps don't even apply to cloud service (extended support)...This option "If retrying later does not help, one recovery option is to redeploy the same workload to a new Cloud Service (extended support), validate it, and then update the DNS CNAME or A record to route traffic to the new service. With proper planning, this can help minimize downtime." is not acceptable, it WILL cost downtime, this is a production 24/7 site.

This is just an update, size not changing or anything, new SSL certificate.

I pay for support but cannot get to the Create Ticket option anymore

I am aware this will move away from cloud service next year, But i don't have time for that now

1 answer

Your answer

Rich Simpson 20 Reputation points

2026-07-25T11:06:09.61+00:00

Yes I have read and check all that applies (most of the troubleshooting steps don't even apply to cloud service (extended support)...This option "If retrying later does not help, one recovery option is to redeploy the same workload to a new Cloud Service (extended support), validate it, and then update the DNS CNAME or A record to route traffic to the new service. With proper planning, this can help minimize downtime." is not acceptable, it WILL cost downtime, this is a production 24/7 site.

This is just an update, size not changing or anything, new SSL certificate.

I pay for support but cannot get to the Create Ticket option anymore

I am aware this will move away from cloud service next year, But i don't have time for that now

Answer 1

This is an allocation failure in Azure Cloud Services (extended support). The service is pinned to the cluster where its first instance was originally allocated, so later updates and scale operations must allocate on that same cluster. If that cluster is near capacity or no longer supports the requested VM size, the update can fail even though the site is currently still running.

Most effective recovery options:

Redeploy to a new cloud service
- Deploy the same workload to a new Cloud Service (extended support).
- Update the DNS CNAME or A record to send traffic to the new cloud service.
- After traffic has moved, delete the old cloud service.
- This is the solution most likely to succeed because it allows Azure to choose from all clusters in the region.
- This approach should incur zero downtime.
If VIP swap or swappable services are involved
- Swappable cloud services are allocated to the same cluster.
- If that cluster is constrained, deployment of the paired service can fail.
- The documented recovery is to delete both swappable cloud services and then create new deployments for both so Azure can try allocation across all clusters in the region.
- Warning: this creates downtime.

What this means for the current service:

The failure is not necessarily caused by a change in the application package.
Cloud Services (extended support) does not eliminate allocation failures; deployments remain tied to a cluster like Cloud Services (classic).
Retrying later can help for transient capacity issues, but the documented durable fix is redeploying to a new cloud service so the deployment is no longer pinned to the constrained cluster.

References: