Modern AI and data platforms are composed of many cooperating tools and clusters: a user may sign into a central portal, open a governed dataset, launch a notebook, and call an assistant that uses services in another cluster. The workflow seems unified, but identity travels across control‑plane and data‑plane boundaries — and standard single sign‑on (SSO) becomes insufficient.
SSO proves the user at entry, but platform teams need a reliable way to carry that user context into distributed execution environments. Handing raw tokens to every application increases exposure and complicates revocation; requiring each cluster to reimplement identity‑provider logic duplicates effort and creates inconsistent behavior.
This is particularly important for AI and data platforms where data and compute often remain close to where they are produced or governed — regional clusters, separate cloud accounts, on‑premises environments, or specialized execution planes. Users expect a single platform experience across notebooks, catalogs, query tools, dashboards, and assistants.
The central identity gateway pattern
The central identity gateway pattern makes a single service the owner of platform sessions. Data‑plane (regional) gateways no longer run full OIDC flows for each request; instead they call a shared identity‑validation API (for example /gateway/userinfo) to validate the platform session and receive trusted identity claims. Regional gateways enforce local policy and inject standardized identity headers for downstream applications.
Key components of the architecture:
- A central session owner that handles OIDC authorization code flow, session creation, refresh and logout
- A shared session store (e.g., Redis) holding opaque session IDs and a HTTP‑only cookie scoped to the platform domain
- Stateless regional gateways that delegate validation to the central gateway
- A small, well‑defined identity‑validation endpoint that services trust
Applications no longer need to parse tokens, refresh credentials, or integrate directly with the identity provider; they consume identity from a consistent interface returned by the central gateway.
How it works — three primary flows
Login
If the browser has no valid platform session, a regional gateway redirects the user to the central identity gateway. The central gateway performs the OIDC authorization code exchange with the organization’s identity provider, stores the session in the shared store with a TTL, and sets an HTTP‑only session cookie. That cookie becomes the user’s platform credential for the session.
Per‑request validation
On subsequent requests the regional gateway sends the session cookie to /gateway/userinfo. The central gateway looks up the session and returns identity claims (user ID, email, groups, roles, session metadata). The regional gateway injects trusted identity headers and forwards the request to the application. This keeps normal request paths lightweight: no full OIDC exchange or IdP call is required per request, only a session lookup and a gateway‑to‑gateway validation call.
Token refresh and logout
When an access token nears expiry, the central gateway refreshes it using the stored refresh token and updates the session record in the shared store; all regional gateways observe the same state. For logout, the central gateway deletes the session record — on the next request all regional gateways see an invalid session and deny access or redirect to login, making logout immediate and platform‑wide.
Why this improves on distributed session ownership
In a distributed model each gateway owns its login flow, session store, refresh logic and logout behavior. That works at small scale but creates problems as the platform grows:
- Sessions are scoped to where they were created, forcing separate logins per service
- Logout is local and may leave active sessions elsewhere
- Token refresh is uncoordinated, increasing upstream IdP load and divergent states
- Identity context is inconsistent; downstream services duplicate auth logic
- New services inherit complex, repeated integrations
Centralized session ownership reduces repeated logins, standardizes downstream identity via trusted headers or claims, coordinates refresh and logout, and simplifies adding new tools because they consume a single platform contract.
Security and reliability guardrails
Centralizing sessions makes the identity gateway a critical service, so teams should design accordingly:
- Use secure service‑to‑service authentication between regional gateways and the central gateway (mutual TLS, workload identity, or signed internal tokens) to prevent untrusted callers
- Strip inbound identity headers and only trust headers injected by the gateway layer
- Store only necessary session data; use short access‑token lifetimes, explicit TTLs, refresh‑token protection, encryption in transit and proper access controls for the session store
- Define failure behavior: some platforms should fail closed (deny requests if the identity gateway or store is unavailable), others may allow short‑lived cached validation for resilience
- Log validation, refresh and logout events to maintain an auditable trail
Operational benefits: reduced load on upstream IdP
A less obvious advantage is lower load on upstream identity systems. In a distributed model each regional gateway may perform separate token exchanges, refreshes and policy evaluations as users move across tools. With a central gateway the IdP is called once per login; regional gateways validate against the shared session. As clusters and tools multiply, upstream load scales more with active users than with the number of user‑tool‑cluster combinations.
Enabling unified AI and data workflows
Centralized session validation enables higher‑level platform capabilities: a unified platform shell can embed many tools and assistants behind one login while each embedded application validates requests through the gateway layer. AI assistants can resolve a user’s identity via the platform session and pass trusted identity context to backend tools, allowing assistant actions to inherit the user’s RBAC scope without broad service credentials or per‑tool logins.
How to apply the pattern
Start by inventorying where sessions are created now: which gateways run OIDC flows, which services parse tokens, which headers downstream apps trust, and how logout works. Define the central contract:
- Which service owns session creation?
- What claims will /gateway/userinfo return?
- Which gateway layer may inject identity headers?
- How long should platform sessions live?
- How will refresh and logout be audited?
- What happens if the session store is unavailable?
Migrate incrementally: pick one regional gateway or a related service group and replace local session validation with a central validation call. Keep the application‑facing identity interface stable so downstream services need minimal changes. Expand gateway by gateway until enforcement points read from the same source of session truth.
The pattern does not require proprietary middleware: standard OIDC libraries, Redis or other low‑latency session stores, and common Kubernetes ingress or service‑mesh integrations suffice.
Experience from practice
NVIDIA’s internal implementation of this pattern reduced repeated login events by 55% across developer platforms spanning Kubernetes clusters in AWS and OCI. It also provided a reusable foundation for unified developer portals, consistent logout, lower upstream IdP load, and AI assistants that act with delegated user identity across data planes.
Closing thought
Distributed session state is an architectural debt that often begins as repeated login prompts but grows into duplicated auth logic, inconsistent logout, unnecessary IdP load, and fragmented user context. Separating session ownership from request enforcement with a central identity gateway addresses the root cause: one service owns login, refresh, validation and logout, while regional gateways enforce policy by reading the shared session record.
