This page describes best practices for allocating network addresses to Kubernetes Pods and Services running on your Google Distributed Cloud Edge installation.
For Cloud control plane clusters, Distributed Cloud Edge Pod and
Distributed Cloud Edge Service address blocks must not overlap
with the reserved CIDR blocks for the
corresponding region. For example, you must not assign the 10.128.0.0/20 CIDR
block in the us-central1 region.
When creating a Distributed Cloud Edge cluster, you can specify an IPv4 CIDR block for your Distributed Cloud Edge Pods and Distributed Cloud Edge Services. For IPv4, use the RFC 1918 address range.
Each Distributed Cloud Edge cluster accepts a single contiguous Distributed Cloud Edge Pod CIDR block and a single contiguous Distributed Cloud Edge Service CIDR block. The Distributed Cloud Edge Service CIDR block covers only ClusterIP Services running within the target Distributed Cloud Edge cluster. For external-facing Distributed Cloud Edge Services, see Load balancing.
You must ensure the following:
- The Distributed Cloud Edge Pod CIDR block and the Distributed Cloud Edge Service CIDR block must not conflict with each other or with any other CIDR blocks on your local network.
- The Distributed Cloud Edge node CIDR block must not conflict with the Distributed Cloud Edge management CIDR blocks.
- Distributed Cloud Edge load balancer virtual IP pools must not conflict across Distributed Cloud Edge clusters.
- If you are connecting to a Virtual Private Cloud (VPC) network by using Cloud VPN, the Pod and Service CIDR blocks must not conflict with any CIDR blocks on your VPC network.
- To prevent indeterministic behavior, the CIDR blocks for Distributed Cloud Edge clusters, your private network, and VPC subnetworks used for Distributed Cloud Edge connectivity must not overlap.
Distributed Cloud Edge automatically allocates portions of the
specified Distributed Cloud Edge Pod CIDR block as fixed-size Pod
sub-CIDR blocks for each node in the zone based on the node's configured maximum
Pod count. By default, Distributed Cloud Edge sets the maximum
Pod count per node to 128, which results in the allocation
of a /24 CIDR block per node. You can change this count by using the
default-max-pods-per-node flag. Distributed Cloud Edge
automatically scales the Pod CIDR size based on the value that you specify.
The following table lists the Pods-per-node counts and their corresponding CIDR sizes:
| Maximum Pods per node | IPv4 Pod CIDR block size |
|---|---|
| 32 | /26 |
| 33-64 | /25 |
| 65-128 | /24 |
| 129-256 | /23 |
After you create the Distributed Cloud Edge cluster, you cannot modify the CIDR block and Pods-per-node values described in this section. You must delete and re-create the cluster with the new values.