> ## Documentation Index > Fetch the complete documentation index at: https://docs.xloud.tech/llms.txt > Use this file to discover all available pages before exploring further. # Load Balancer Pools > Create and manage backend member pools, configure traffic distribution algorithms, and handle session persistence in Xloud Load Balancer. ## Overview A pool is a collection of backend member instances that receive traffic from a listener. Pools define how traffic is distributed across members (algorithm), whether sessions are sticky (persistence), and which protocol the pool uses internally. Each listener has a default pool; additional pools can be used for L7 policy-based routing. **Prerequisites** * An active Xloud account with appropriate permissions * Access to the **Xloud Dashboard** or CLI configured with credentials * API credentials sourced (`source openrc.sh`) *** ## Distribution Algorithms | Algorithm | Description | Best For | | ------------------- | --------------------------------------------------------------- | ---------------------------------------------------------- | | `ROUND_ROBIN` | Distributes requests evenly across all UP members | Stateless applications with equal capacity members | | `LEAST_CONNECTIONS` | Sends new requests to the member with fewest active connections | Long-lived connections with variable request duration | | `SOURCE_IP` | Routes requests from the same client IP to the same member | Stateful applications without cookie-based persistence | | `SOURCE_IP_PORT` | Routes based on client IP + port combination | Symmetric NAT environments requiring deterministic mapping | *** ## Create a Pool Open your load balancer in **Network > Load Balancers** and select the **Pools** tab. Click **Create Pool**. | Field | Description | | ----------------------- | ------------------------------------------------------ | | **Name** | Pool display name | | **Protocol** | Must match or be compatible with the listener protocol | | **Algorithm** | Traffic distribution method | | **Session Persistence** | Sticky session configuration (optional) | After pool creation, select the pool and click the **Members** sub-tab. Click **Add Member** to register backend instances. | Field | Description | | ------------------------ | ------------------------------------------------------------- | | **IP Address** | Backend instance IP | | **Protocol Port** | Port your application listens on | | **Weight** | Relative traffic weight (default: 1) | | **Monitor Address/Port** | Override health check target if different from member address | ```bash title="Create pool linked to listener" theme={null} openstack loadbalancer pool create \ --name pool-http \ --lb-algorithm ROUND_ROBIN \ --listener listener-http \ --protocol HTTP ``` ```bash title="Create standalone pool (for L7 routing)" theme={null} openstack loadbalancer pool create \ --name pool-api \ --lb-algorithm LEAST_CONNECTIONS \ --loadbalancer prod-web-lb \ --protocol HTTP ``` *** ## Manage Pool Members Navigate to your pool and click the **Members** sub-tab. Use **Add Member** to register instances and **Delete** to remove members that are decommissioned. ```bash title="Add a member" theme={null} openstack loadbalancer member create \ --subnet-id \ --address \ --protocol-port 8080 \ pool-http ``` ```bash title="List pool members with health status" theme={null} openstack loadbalancer member list pool-http \ -c name -c address -c protocol_port -c operating_status ``` ```bash title="Update member weight" theme={null} openstack loadbalancer member set pool-http \ --weight 2 ``` ```bash title="Remove a member" theme={null} openstack loadbalancer member delete pool-http ``` *** ## Session Persistence Session persistence routes subsequent requests from the same client to the same backend member, enabling stateful applications to work behind the load balancer. The load balancer inserts a session cookie. Clients are routed to the member that served their first request: ```bash title="Create pool with HTTP cookie persistence" theme={null} openstack loadbalancer pool create \ --name pool-stateful \ --lb-algorithm ROUND_ROBIN \ --listener listener-http \ --protocol HTTP \ --session-persistence type=HTTP_COOKIE ``` Routes requests from the same client IP to the same member. Works at Layer 4 but breaks when clients are behind NAT with shared IP addresses: ```bash title="Create pool with source IP persistence" theme={null} openstack loadbalancer pool create \ --name pool-sourceip \ --lb-algorithm ROUND_ROBIN \ --listener listener-http \ --protocol HTTP \ --session-persistence type=SOURCE_IP ``` The load balancer reads an existing cookie set by your application: ```bash title="Create pool with application cookie persistence" theme={null} openstack loadbalancer pool create \ --name pool-appcookie \ --lb-algorithm ROUND_ROBIN \ --listener listener-http \ --protocol HTTP \ --session-persistence "type=APP_COOKIE,cookie_name=JSESSIONID" ``` *** ## Update Pool Settings ```bash title="Change distribution algorithm" theme={null} openstack loadbalancer pool set pool-http \ --lb-algorithm LEAST_CONNECTIONS ``` ```bash title="Remove session persistence" theme={null} openstack loadbalancer pool set pool-http \ --no-session-persistence ``` *** ## Next Steps Configure health probes to automatically remove unhealthy members from pools. Configure the listeners that route traffic to your pools. Full walkthrough for creating a load balancer with pool and health monitor. Resolve member OFFLINE status and pool connectivity issues.