Upgrade and scale an Azure API Management instance
Customers can scale an Azure API Management (APIM) instance by adding and removing units. A unit is composed of dedicated Azure resources and has a certain load-bearing capacity expressed as a number of API calls per month. This number does not represent a call limit, but rather a maximum throughput value to allow for rough capacity planning. Actual throughput and latency vary broadly depending on factors such as number and rate of concurrent connections, the kind and number of configured policies, request and response sizes, and backend latency.
Capacity and price of each unit depends on the tier in which the unit exists. You can choose between four tiers: Developer, Basic, Standard, Premium. If you need to increase capacity for a service within a tier, you should add a unit. If the tier that is currently selected in your APIM instance does not allow adding more units, you need to upgrade to a higher-level tier.
The price of each unit and the available features (for example, multi-region deployment) depends on the tier that you chose for your APIM instance. The pricing details article, explains the price per unit and features you get in each tier.
The pricing details article shows approximate numbers of unit capacity in each tier. To get more accurate numbers, you need to look at a realistic scenario for your APIs. See the Capacity of an Azure API Management instance article.
To follow the steps from this article, you must:
Have an active Azure subscription.
Have an APIM instance. For more information, see Create an Azure API Management instance.
Understand the concept of Capacity of an Azure API Management instance.
This feature is available in the Premium, Standard, Basic and Developer tiers of API Management.
Upgrade and scale
You can choose between four tiers: Developer, Basic, Standard and Premium. The Developer tier should be used to evaluate the service; it should not be used for production. The Developer tier does not have SLA and you cannot scale this tier (add/remove units).
Basic, Standard and Premium are production tiers that have SLA and can be scaled. The Basic tier is the cheapest tier which has SLA and it can be scaled up to 2 units, Standard tier can be scaled to up to four units. You can add any number of units to the Premium tier.
The Premium tier enables you to distribute a single Azure API Management instance across any number of desired Azure regions. When you initially create an Azure API Management service, the instance contains only one unit and resides in a single Azure region. The initial region is designated as the primary region. Additional regions can be easily added. When adding a region, you specify the number of units you want to allocate. For example, you can have one unit in the primary region and five units in some other region. You can tailor the number of units to the traffic you have in each region. For more information, see How to deploy an Azure API Management service instance to multiple Azure regions.
You can upgrade and downgrade to and from any tier. Note that upgrading or downgrading can remove some features - for example, VNETs or multi-region deployment, when downgrading to Standard or Basic from the Premium tier.
The upgrade or scale process can take from 15 to 45 minutes to apply. You get notified when it is done.
API Management service in the Consumption tier scales automatically based on the traffic.
Use the Azure portal to upgrade and scale
- Navigate to your APIM instance in the Azure portal.
- Select Scale and pricing from the menu.
- Pick the desired tier.
- Specify the number of units you want to add. You can either use the slider or type the number of units.
If you choose the Premium tier, you first need to select a region.
- Press Save.
Downtime during scaling up and down
If you are scaling from or to the Developer tier, there will be downtime. Otherwise, there is no downtime.