Limitations

Following are a few limitations that you can encounter while using both Public and Private Node Pools:

• The maximum number of pods supported per node is 110. It is a Kubernetes default value.

• The recommended maximum number of nodes per node pool is 20.

• The maximum number of nodes in a node pool is 100.

• A total of 500 node pools per cluster is supported.

• The recommended maximum number of node pools per cluster are 50.

• The maximum number of supported nodes per cluster is 5000.

• While a node can theoretically support a maximum of 20 volumes, the practical limit can be lower because each node has only 24 Peripheral Component Interconnect (PCI) slots shared among all peripherals.

• Managed Kubernetes clusters use Block Storage as the underlying storage system. As a result, Block Storage volume limits and performance thresholds apply to your cluster nodes. Before provisioning persistent volumes, see Limitations.

Control plane

The control plane is subject to the following resource limits:

• Each kube-apiserver replica is limited to 8 GiB of memory.

• Each cluster runs two kube-apiserver replicas, resulting in a maximum of 16 GiB of memory for the API server across the cluster. This memory is not shared between replicas; a single replica cannot exceed 8 GiB.

If the API server's memory consumption reaches this limit, the affected replica is restarted. This can cause temporary interruptions in API availability, for example, failing kubectl commands or delayed reconciliation. Workloads running on your nodes are not directly affected, but controllers and operators that depend on the Kubernetes API may be.

To stay within the limit, avoid patterns that increase API server memory consumption:

• A very high number of objects in the cluster.

• Frequent full LIST requests without pagination or field selectors.

• A large number of concurrent watch clients.

Private Node Pools

Following are a few limitations that you can encounter while using Private Node Pools:

• Managed Kubernetes clusters for Private Node Pools are bound to one region. When you create a node pool, you need to provide a data center, which has to be in the same location as defined in the cluster. You can create Private Node Pools only in a Virtual Data Center (VDC) that shares the region with the managed Kubernetes cluster.

• Kubernetes services of type LoadBalancer are currently not supported.

• The static node Internet Protocol (IP) addresses are not supported.