Executive summary
Feature comparison
Node scaling
Autopilot advantage: PV-aware zone provisioning prevents the runaway scale-up problem
where pods with zonal PersistentVolumes stay unschedulable because nodes are provisioned in
the wrong zone. Autopilot resolves the PV’s zone from the PVC chain and provisions in the
correct zone automatically.
CAST AI advantage: Broad multi-cloud support (AWS, Azure, GCP) today.
Pod right-sizing (vertical optimization)
Both support in-place resizing on K8s 1.33+ via KEP-1287. The differentiators are in the
recommendation algorithm and operational transparency.
Autopilot advantage: Full algorithm transparency. Every recommendation includes the
percentiles, buffer, data source, sample count, and hysteresis decisions — so when a
recommendation oscillates or seems wrong, you can see exactly why. CAST AI’s recommendations
are opaque.
Cluster rebalancing
Autopilot advantage: Rolling drain mode doesn’t require double capacity. It drains nodes
in small batches and lets the scaler provision right-sized replacements. Provision-first
approaches require enough headroom to run the old and new fleet simultaneously.
Scheduled scaling
Autopilot advantage: CAST AI doesn’t have scheduled scaling. If you have predictable
traffic patterns (morning login surges, batch processing windows), Autopilot can pre-warm
pods before the burst arrives.
Observability & dashboard
Autopilot advantage: GCP managed-service monitoring is unique to Autopilot. It surfaces
Cloud SQL CPU, Redis memory, NAT port exhaustion, and more in the same dashboard with health
thresholds and Slack alerts.
CAST AI advantage: Their SaaS dashboard requires zero infrastructure — no Prometheus, no
port-forwarding.
Architecture differences
Data flow
Autopilot keeps everything within the cluster:Node provisioning
Autopilot (heterogeneous mode):- Provisions GCE VMs directly via the Instances API.
- Clones bootstrap metadata from existing GKE nodes.
- Kubelet uses a ServiceAccount token for initial auth, then a CSR for the node certificate.
- Autopilot handles CSR approval, pod CIDR assignment, and taint removal.
- VMs are fully integrated into the K8s cluster networking and tracked in the NodeScalingPolicy status.
- Creates empty GKE node pools as placeholders (
cast-pool,cast-pool-arm). - Provisions standalone GCE VMs named
gke-<cluster>-cast-pool-<hash>. - VMs are NOT members of the GKE node pool despite the naming.
- Deleting the
cast-poolnode pool does NOT delete the standalone VMs.
Conflict prevention
Autopilot includes a cluster-level CAST AI detector that scans every 5 minutes for CAST AI agent pods, webhooks, and CRDs. When detected, all Autopilot policies are forced to passive mode regardless of their configured mode, preventing the two systems from fighting over resource values. The dashboard shows a warning banner and the health endpoint reports the conflict.Cost comparison
Autopilot total cost
No per-node fees. No percentage-of-savings fees. Cost is fixed regardless of cluster size.
CAST AI pricing
CAST AI charges based on savings delivered — typically ~20–30% of realized savings on the Growth plan, custom for Enterprise. On a cluster spending 2,000), the fee would be ~48/mo delivers the same optimization.When to choose each
Choose Autopilot when:- Running on GKE (EKS support is being built out)
- Data residency matters — metrics must stay in-cluster
- You want full algorithm transparency and customization
- In-place pod resizing (zero-downtime) is important
- You need GCP managed-service monitoring in the same dashboard
- You have predictable traffic patterns that benefit from scheduled scaling
- You want fixed-cost optimization without savings-based fees
- Running across AWS, Azure, and GCP today
- You prefer a fully managed SaaS solution with no infrastructure to maintain
- Your team doesn’t want to operate Prometheus or manage controller upgrades