Migrating Azure API Management from STV01 to STV02 Platform: Migration Guide

 

Microsoft has officially Announced that Azure API Management instances hosted on the stv1 platform will be retired by 31 August 2024. If you have instances hosted on the stv1 platform, migrate them to the stv2 platform before that date to avoid service disruptions.

This blog post will help you in how to migrate the Azure API Management service from STV01 to STV02, covering both VNet injected and non-VNet injected scenarios. Options are featured that explain how to use new or existing subnets. Furthermore, it describes the process of deleting old STV01 compute resources.

Azure API Management enables an organization to publish, secure, transform, and monitor APIs with efficiency. In the ever-evolving tiers of service in Azure, STV01 to STV02 tier migration offers much-improved performance and scalability in various areas. However, this kind of migration will call for careful planning, where the decision has to be made between a new subnet or an existing one for the VNet-integrated migration process. 

Before you migrate Azure API Management from the STV01 to STV02, you need to understand the difference between these two tiers:

STV01: An older version with certain limitations in scalability, performance, and availability of various features.

• STV02: This new version has better performance as well as scalability, with better security features as well. There is the implementation of zone redundancy, better throughput, and lower latency.

Migrating to STV02 allows organizations to leverage such upgrades and facilitates a superior API management solution.

Pre-Migration Activities

a. Assessment of Existing Configuration

1. API Inventory: Document all APIs, with the products, policies, and subscriptions, that are listed in the APIM.

2.Check VNet Integration: If the APIM is VNet-integrated, the stipulation shall impact the approach towards migration.

3.Backup Data as a Precaution: The backup should be taken for API definitions, products, policies, and all other custom settings.

b. Downtime Scheduling (if necessary)

• VNet-Injected Instances: It might require downtime because of the reconfiguration of the network, especially for changes at the subnet level.

• Non-VNet-Injected Instances: Generally, this will be migrated with minimal downtime, though plan for a Change Window always.



c Update DNS Records

If your APIM is using custom DNS names, then update the DNS records to point to the new STV02 endpoint readied after migration.


Migration Activities: New Subnet or Existing Subnet

Prerequisites

  • A network security group must be attached to each subnet, and NSG rules for API Management on the stv2 platform must be configured. The following are minimum connectivity settings:
    • Outbound to Azure Storage over port 443
    • Outbound to Azure SQL over port 1433
    • Outbound to Azure Key Vault over port 443
    • Inbound from Azure Load Balancer over port 6390
    • Inbound from Api Management service tag over port 3443
    • Inbound over port 80/443 for clients calling API Management service
    • The subnet must have service endpoints enabled for Azure Storage, Azure SQL, and Azure Key Vault


  • The address space of each existing subnet must be large enough to host a copy of your existing service side-by side with your existing service during migration.
  • Other network considerations:
    • Turn off any auto scale rules configured for API Management instances deployed in the subnet. Auto scale rules can interfere with the migration process.
    • If you have multiple API Management instances in the same subnet, migrate each instance in sequence. We recommend that you promptly migrate all instances in the subnet to avoid any potential issues with instances hosted on different platforms in the same subnet.

VNET Injected Migration: New Subnet or Existing Subnet

For APIM instances that are configured with Virtual Network, there are two major options for migrating from STV10 to STV02: either new subnet or existing subnet. A. New Subnet Advantages: Isolation: The new APIM instance is totally isolated from the old instance, and isolation helps in minimizing the disruption during migration. Clean Slate: It's a fresh opportunity to reconfigure network security settings and further polish the subnet for new workload. 

Migration Steps:

1. Create a new subnet

b. Do the following step on Azure Portal: Create a new subnet inside the existing VNet for your existing APIM instance.

 2. New STV02 Instance Provisioning: a. Need to create a new instance of APIM with the required tier STV02 and ensure to use the latest subnet.

3. APIs and Configurations Migration:

a. Export the APIs and Policies: APIs, Policies, and Configurations from STV01 should be exported using the Azure portal or some PowerShell scripts.

4.Network Security Group Update: Network Security Groups and firewall rules enable access between the new STV02 instance and your backend services.

5.Test and Validate: Ensure that all API's are working as expected and similarly network integration established correctly.

6.Switch Over: Update DNS records to point to the new STV02 endpoint and ensure the old STV01 instance is left unused

Existing Subnet 

Easier Configuration: There is no need to provision a new subnet and configure NSGs in the subnets

Migration is Faster: Migration time is minimal as all your existing settings and policies with respect to your network are retained.

Create New STV02 Instance:

1. Add a new instance of APIM with the appropriate tier, STV02, under the same subnet.

2. Switch APIs and configurations:

3.Export APIs and Policies: Export all APIs, policies, and configurations from the old STV01 or instance with Azure Portal or with the use of PowerShell scripts.

o Import to STV02: Import all the exported settings to the new instance.

o Ensure NSGs and firewall rules are properly configured for the new instance on the old subnet.

4.Verification and Validation:

o Ensure all APIs are working fine, and the network is configured as expected.

5.Switch Over:

o Update DNS entries to point to the new STV02 endpoint and ensure that the old STV01 instance is not reachable anymore.


Automatic Deletion Options:
1. 15-Minute Deletion Option:

o Quick Cleanup: This retains the STV01 instance for just 15 minutes after the switch-over. This best works for a user who wants to dispose of the old instance as fast as possible to save costs that could be unnecessary.

o Immediate Impact: This option should work well only when you are convinced that the new STV02 instance has been fully tested. This is because you are allocated very little time in case you want to reverse.

2. 48-Hour Deletion Option:

o Grace Period: This option would make sure that STV01 instance would get automatically deleted after 48 hours of switch-over. This option gives grace period in which the new STV02 instance can be tested and verified for any misconfigurations.

o Safety Net: This option provides window to check that new STV02 instance does not face any critical issues during initial usage, at which time the old instance could be reverted.

Auto-delete option can be configured as given below:

• As we are following through the migration steps in the Azure portal, select the preferred time of deletion when you are performing risk and confident in your testing—either 15 minutes or 48 hours.


(Optional) Migrate back to original subnet

If you migrated and changed to a new subnet, optionally migrate back to the original subnet you used in each region. To do so, update the VNet configuration again, this time specifying the original VNet and subnet in each region. As in the preceding migration, expect a long-running operation, and expect the VIP address to change.



Non-VNet Injected Migration

For such APIM instances that are not directly injected with a Virtual Network, migration is less critical:

1.  Create a New STV02 Instance:

o From Azure portal, create a new API Management instance with STV02 tier.

2. Migrate APIs and Configurations:

Export APIs and Policies: Export all APIs, policies, and configurations from STV01.

o Import to STV02: Import the exported configurations into the new STV02 instance.

3.Test and Validate:

o Ensure that all APIs are working fine without any connectivity problem from backend services.

4. Switch Over:

o Update DNS records to point to the new endpoint, STV02, and ensure that the old endpoint, STV01, is eventually not accessed.

5. Automatically Remove the Old STV01 Compute Resources

When it is confirmed that the migrated resources are operational in STV02 and the new instance of it functions normally, then the old compute resources of STV01 will be scheduled to get automatically deleted. 

Post Migration Activities

  • Steps after Migration check on the status of the APIM should be Online and Platform Version should be stv02 or stv02.1



  • Test on the API are communicating with the backends as expected after the network dependencies are reverted.


Additional Checks

a. Monitor Performance

• Monitor the performance of new APIM using Azure Monitor and Insights.

b. Update Documentation

•  Ensure all team members and other stakeholders are aware of the changes and update documentation

c. Review Security settings

• Review security set up and policies and ensure they are aligned with the policies of the organization






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