Node pool scale-out may fail when instance inventory is insufficient or an ECS instance type is unavailable in a zone. Use elastic strength to evaluate node pool configuration availability and instance supply health, and follow the configuration recommendations ACK shows for node pools with poor elastic strength.
How it works
Not every theoretical resource pool can provision nodes. Inventory shortages, resource constraints, and configuration mismatches reduce the available count below the theoretical maximum. For example, the c6e instance family supports enterprise SSDs but not standard SSDs.
The following figure shows a node pool with two zones, two instance types, and a specific disk type. Although multiple resource pools exist in theory, only one is available due to inventory shortages, instance deployment status, and disk constraints.
View scalability details
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Log on to the Container Service Management Console. In the left navigation pane, click Clusters.
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On the Clusters page, click the target cluster name. In the left navigation pane, choose Nodes > Node Pools.
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On the Node Pools page, check the Status column. A Scalability Level: Weak label indicates an elastic strength score of 0 or less.
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Click Scalability Level: Weak to open the Scalability Details dialog box.
Understand and fix scalability issues
The Scalability Details dialog box shows unavailable resource pools and their causes. Issues fall into two categories.
Resource constraint issues
Configuration mismatches that invalidate a resource pool. Fix by adjusting your node pool configuration.
| Result | Recommended fix |
|---|---|
| Image and instance type mismatch | Adjust the instance types in the node pool |
| System disk and instance type mismatch | Adjust the instance types or system disk type in the node pool |
| Data disk and instance type mismatch | Adjust the instance types or data disk type in the node pool |
| Instance type does not support IPv6 | Adjust the instance types in the node pool |
| vSwitch does not exist | Adjust the vSwitches in the node pool |
Instance inventory issues
The instance type is valid in the zone but temporarily out of stock. Add more zones or instance types to increase available resource pools.
| Result | Recommended fix |
|---|---|
| Instance type not deployed | Adjust the instance types in the node pool |
| Instance type is out of stock | Adjust the instance types in the node pool |
Improving elastic strength
Each valid zone–instance type combination adds one resource pool. To improve elastic strength, configure vSwitches across multiple zones and specify instance types with sufficient inventory.
Adjust your node pool in Create and manage a node pool.
Next steps
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ECS instance type configuration recommendations — choose instance types widely available across zones to maximize resource pool count.