Creating Service Association Link between Azure subnet and GitHub gives Subnet In use message

Question

Creating Service Association Link between Azure subnet and GitHub gives Subnet In use message

Walter V 5

When creating a Service Association Link with GitHub, I get a 'The subnet is in use by another resource' message.

Documentation being followed:

https://docs.github.com/en/organizations/managing-organization-settings/configuring-private-networking-for-github-hosted-runners-in-your-organization

Command:

az resource create --resource-group $RESOURCE_GROUP_NAME --name $NETWORK_SETTINGS_RESOURCE_NAME --resource-type GitHub.Network/networkSettings --properties "{ \"location\": \"$AZURE_LOCATION\", \"properties\" : { \"subnetId\": \"/subscriptions/$SUBSCRIPTION_ID/resourceGroups/$RESOURCE_GROUP_NAME/providers/Microsoft.Network/virtualNetworks/$VNET_NAME/subnets/$SUBNET_NAME\", \"businessId\": \"$DATABASE_ID\" }}" --is-full-object --output table --query "{GitHubId:tags.GitHubId, name:name}" --api-version $API_VERSION

Output:

(SubnetInUse) The subnet is in use by another resource.
Code: SubnetInUse
Message: The subnet is in use by another resource.

I had this subnet associated with GitHub previously, then had it removed to debug network issues. Now I am trying to connect it back to GitHub. There are currently no NICs or other Azure resources attached to this subnet.

Is the error 'The subnet is in use by another resource.' coming from Azure or GitHub?

Venkatesan S 6,525 Reputation points Microsoft External Staff Moderator

2026-03-24T20:42:06.0233333+00:00
Hi Walter V,

Thanks for reaching out in Microsoft Q&A forum,

Message: The subnet is in use by another resource.

The “The subnet is in use by another resource” error you are seeing is coming from Azure, not from GitHub directly. It is Azure’s network‑layer validation on the subnet resource when you try to create or update the GitHub.Network/networkSettings (Service Association Link / SAL) resource.

Even though you say there are no NICs or other Azure resources attached to the subnet, the error usually means one of the following:

The subnet is still delegated to GitHub.Network/networkSettings from a previous SAL, or the delegation was not fully cleaned up.

There is a residual or stale SAL reference (old GitHub.Network/networkSettings resource or delegation) that Azure still sees as “in use,” even if the resource looks deleted.

The subnet is referenced by another service (e.g., an internal SAL, another provider, or a pending cleanup state) that Azure’s subnet‑in‑use check still catches.

GitHub’s networkSettings resource is just another Azure resource that delegates the subnet to GitHub’s private‑networking service; Azure enforces that such a delegated subnet cannot be used for anything else.

Check the below steps:

Verify delegation on the subnet Run:
az network vnet subnet show \ --resource-group $RESOURCE_GROUP_NAME \ --vnet-name $VNET_NAME \ --name $SUBNET_NAME \ --query "delegations"
If you see a delegation to GitHub.Network/networkSettings, that confirms the subnet is still considered “in use” by that delegation.

Check for existing GitHub.Network/networkSettings resource List all such resources in the subscription filtered by subnetId:
az resource list \ --resource-type "GitHub.Network/networkSettings" \ --resource-group $RESOURCE_GROUP_NAME \ --query "[].{name:name,subnetId:properties.properties.subnetId}"
If the subnet ID appears on any remaining networkSettings resource, delete that resource first:
az resource delete \ --resource-group $RESOURCE_GROUP_NAME \ --name $EXISTING_NETWORK_SETTINGS_NAME \ --resource-type GitHub.Network/networkSettings

Kindly let us know if the above helps or you need further assistance on this issue.

Please “up-vote” if the information helped you. This will help us and others in the community as well.
Walter V 5 Reputation points

2026-03-24T22:25:30.5+00:00
Unfortunately both calls gave empty responses:

az network vnet subnet show --resource-group rg-PnC-Private-Runners --vnet-name vnet-cpoe-github-runners-pnc-01 --name subnet-01 --query "delegations" []

az resource list --resource-type "GitHub.Network/networkSettings" --resource-group rg-PnC-Private-Runners []

But I am still getting the message 'The subnet is in use by another resource.'

Can I assume that the orphaned connection is on the GitHub side, and something I will need to connect with GitHub support team on?
Venkatesan S 6,525 Reputation points Microsoft External Staff Moderator

2026-03-24T23:11:55.0066667+00:00
Hi Walter V •,

Could you please run this below query? and share the output.

az network vnet subnet show --resource-group rg-PnC-Private-Runners --vnet-name vnet-cpoe-github-runners-pnc-01 --name subnet-01

Walter V 5

Here is the output. There is no reference to the previous delegation to GitHub.

{
  "addressPrefix": "<Internal_Subnet>/26",
  "defaultOutboundAccess": true,
  "delegations": [],
  "etag": "W/\"3b3720b9-3551-49fa-80dd-e74295f6d11b\"",
  "id": "/subscriptions/<Subscription_ID>/resourceGroups/rg-PnC-Private-Runners/providers/Microsoft.Network/virtualNetworks/vnet-cpoe-github-runners-pnc-01/subnets/subnet-01",
  "name": "subnet-01",
  "networkSecurityGroup": {
    "id": "/subscriptions/<Subscription_ID>/resourceGroups/rg-PnC-Private-Runners/providers/Microsoft.Network/networkSecurityGroups/vnet-cpoe-github-runners-pnc-01_nsg",
    "resourceGroup": "rg-PnC-Private-Runners"
  },
  "privateEndpointNetworkPolicies": "Enabled",
  "privateLinkServiceNetworkPolicies": "Enabled",
  "provisioningState": "Succeeded",
  "resourceGroup": "rg-PnC-Private-Runners",
  "routeTable": {
    "id": "/subscriptions/<Subscription_ID>/resourceGroups/rg-PnC-Private-Runners/providers/Microsoft.Network/routeTables/vnet-cpoe-github-runners-pnc-01_rt",
    "resourceGroup": "rg-PnC-Private-Runners"
  },
  "type": "Microsoft.Network/virtualNetworks/subnets"
}

Venkatesan S 6,525 Reputation points Microsoft External Staff Moderator

2026-03-25T17:11:28.2666667+00:00

Hi Walter V,

Could you please share the requested details via private message?

1 answer

Your answer

Walter V 5 Reputation points

2026-03-24T22:25:30.5+00:00

Unfortunately both calls gave empty responses:

az network vnet subnet show --resource-group rg-PnC-Private-Runners --vnet-name vnet-cpoe-github-runners-pnc-01 --name subnet-01 --query "delegations" []

az resource list --resource-type "GitHub.Network/networkSettings" --resource-group rg-PnC-Private-Runners []

But I am still getting the message 'The subnet is in use by another resource.'

Can I assume that the orphaned connection is on the GitHub side, and something I will need to connect with GitHub support team on?
Venkatesan S 6,525 Reputation points Microsoft External Staff Moderator

2026-03-24T23:11:55.0066667+00:00

Hi Walter V •,

Could you please run this below query? and share the output.

az network vnet subnet show --resource-group rg-PnC-Private-Runners --vnet-name vnet-cpoe-github-runners-pnc-01 --name subnet-01
Walter V 5 Reputation points

2026-03-25T12:41:24.2466667+00:00

Here is the output. There is no reference to the previous delegation to GitHub.

{ "addressPrefix": "<Internal_Subnet>/26", "defaultOutboundAccess": true, "delegations": [], "etag": "W/\"3b3720b9-3551-49fa-80dd-e74295f6d11b\"", "id": "/subscriptions/<Subscription_ID>/resourceGroups/rg-PnC-Private-Runners/providers/Microsoft.Network/virtualNetworks/vnet-cpoe-github-runners-pnc-01/subnets/subnet-01", "name": "subnet-01", "networkSecurityGroup": { "id": "/subscriptions/<Subscription_ID>/resourceGroups/rg-PnC-Private-Runners/providers/Microsoft.Network/networkSecurityGroups/vnet-cpoe-github-runners-pnc-01_nsg", "resourceGroup": "rg-PnC-Private-Runners" }, "privateEndpointNetworkPolicies": "Enabled", "privateLinkServiceNetworkPolicies": "Enabled", "provisioningState": "Succeeded", "resourceGroup": "rg-PnC-Private-Runners", "routeTable": { "id": "/subscriptions/<Subscription_ID>/resourceGroups/rg-PnC-Private-Runners/providers/Microsoft.Network/routeTables/vnet-cpoe-github-runners-pnc-01_rt", "resourceGroup": "rg-PnC-Private-Runners" }, "type": "Microsoft.Network/virtualNetworks/subnets" }
Venkatesan S 6,525 Reputation points Microsoft External Staff Moderator

2026-03-25T17:11:28.2666667+00:00

Hi Walter V,

Could you please share the requested details via private message?

Answer 1

Walter V 5

There was something that needed to be done on the GitHub side, that required to create a support ticket. After making a support ticket out to GitHub, I am able to make the Service Association Link to github as per the documentation.

https://docs.github.com/en/organizations/managing-organization-settings/configuring-private-networking-for-github-hosted-runners-in-your-organization

Thanks All,

Closing this off.

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Creating Service Association Link between Azure subnet and GitHub gives Subnet In use message

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