Session Management
Web applications need to track user state: login sessions, shopping carts, form progress, user preferences. Storing that state in the application itself limits your ability to scale. Infinispan externalizes session data into a shared, replicated in-memory store so your application instances stay stateless and horizontally scalable.
The problem with local sessions
When sessions live in application memory, every request from a user must reach the same instance. This creates tight coupling between users and servers:
- Sticky sessions: load balancers must route by session affinity, reducing flexibility and creating hot spots.
- Lost sessions on failure: when an instance crashes or restarts, all its sessions disappear. Users get logged out.
- Scaling friction: adding instances doesn’t help if existing sessions can’t migrate.
How Infinispan solves it
Infinispan stores session data in a distributed cache that all application instances share. Sessions are replicated across cluster nodes, surviving instance failures without user disruption.
Any instance can serve any user. No sticky sessions. No session loss. Scale application instances up and down freely. Infinispan handles the state.
What you get
- Session survival: application restarts and node failures don’t affect user sessions. Infinispan replicates data across nodes automatically.
- Automatic expiration: idle sessions are cleaned up with configurable TTL. No manual garbage collection.
- Sub-millisecond access: session reads and writes happen in memory, keeping response times low even under heavy load.
- Elastic scaling: add or remove application instances without migrating sessions. Infinispan rebalances data transparently.
Framework support
Infinispan integrates with major Java frameworks out of the box:
- Quarkus — the
quarkus-infinispan-clientextension provides session storage with minimal configuration. - Spring Boot — Spring Session with the Infinispan store. Annotate your configuration and sessions are externalized.
- WildFly — built-in Infinispan subsystem handles HTTP session clustering. No additional dependencies.
- Tomcat — session manager implementation stores sessions in a remote Infinispan cluster.
When to use this pattern
Session externalization is the right choice when your application needs to:
- Scale horizontally without session affinity constraints.
- Survive rolling deployments and instance failures without logging users out.
- Share session state across multiple application instances or data centers (via cross-site replication).
