# Create a load balancer > Answer a hostname from your origin pools, steered by the client's location, with a fallback pool when the others are down. Source: https://docs.coritan.com/websites/load-balancing/create-a-load-balancer/ In the dashboard: - /dashboard/websites/…/load-balancing: https://www.coritan.com/dashboard/websites A load balancer answers `A` and `AAAA` queries for one hostname in the zone from your origin pools. Create one when a name should resolve to whichever of your servers is healthy, or to the servers nearest each client. ## Before you begin - Create at least one [origin pool](/websites/load-balancing/create-an-origin-pool/) in the zone. **New load balancer…** is available once the zone has one. - The hostname must have no `A`, `AAAA` or `CNAME` records. If it has some, create the pools first, then delete the records on the **DNS** tab just before you create the load balancer, so the name is without answers for as short a time as possible. ## Create the load balancer 1. In the dashboard, go to [Websites](https://www.coritan.com/dashboard/websites), open the domain and select the **Load balancing** tab. 2. Under **Load balancers**, select **New load balancer…**. 3. Enter a **Name** for your own use, such as `api-global`. 4. Enter the **Hostname**: a name under the zone, such as `api` or `eu.api`, or `@` for the domain itself. The hint under the field shows the full name the load balancer answers for. 5. Set the **TTL (s)**, from 5 to 3,600 seconds. Resolvers ask again after this time, so a short TTL moves clients off an unhealthy origin sooner. 6. Choose the **Session affinity**: **None**, or **By client IP** to give each resolver the same origin while it stays healthy. 7. Choose the **Steering**, and for **Geographic** or **Proximity**, how to **Locate the client by** ([Steering](/websites/load-balancing/#steering)). 8. Under **Default pools**, select the pools in the order to try them. Each selected pool shows its place in the order; select it again to take it out. 9. Optionally, choose a **Fallback pool** to answer when no pool above has a healthy origin. The load balancer needs at least one default pool or a fallback pool. 10. For **Geographic** steering, add rules under **By region**, **By country** and **By PoP**. For each, select **Add rule**, choose the region or PoP, or type a two-letter country code such as `DE`, then select the rule's pools in order. 11. Select **Create load balancer**. A **Geographic** load balancer uses the most specific rule that matches: PoP, then country, then region. A client that matches no rule gets the default pools. ## Preview the answer Check what a client in a given place would get before you rely on the load balancer. 1. Open the load balancer's actions menu and select **Preview answers**. 2. Choose a Coritan PoP under **From PoP**, or leave it at **Any (use resolver IP)** and enter a resolver's address under **Resolver IP**. 3. Choose the **Type**, `A` or `AAAA`, and select **Preview answer**. The panel shows the **Answer**, which pool and rule chose it under **Chosen by**, the **Pool order** steering produced, and where Coritan placed the client under **Client seen as**. The preview uses the origins' current health. Select **Hide preview** in the menu to close it. ## Change, turn off or delete a load balancer - To change it, open its actions menu, select **Edit load balancer…**, make the change and select **Save load balancer**. - To stop it answering, turn off its **Enabled** switch in the table, or **Load balancer enabled** in its dialog. While it is off, the name gets no `A` or `AAAA` answers. - To delete it, open its actions menu, select **Delete load balancer…**, type its full hostname, such as `api.example.com`, and select **Delete load balancer**. > [!WARNING] > A deleted load balancer stops answering at once, and the name has no `A` or `AAAA` answers until you add records for it on the **DNS** tab. Its pools and their origins stay. ## Result The dashboard confirms `Load balancer api.example.com created.`, and the load balancer appears under **Load balancers** with its **Steering** and **Pools**. Ask a Coritan nameserver from a terminal; each answer holds one origin's address: ```bash dig @ns1.coritan.com api.example.com A +short ``` ## Troubleshooting `Hostname already has A/AAAA/CNAME records; remove them before creating a load balancer` : Delete the name's `A`, `AAAA` and `CNAME` records on the **DNS** tab, then create the load balancer. `A load balancer already owns this hostname` : Another load balancer in the zone answers for that name. Edit it instead, or choose another hostname. `Choose at least one default pool or a fallback pool.` : Select a pool under **Default pools**, or choose a **Fallback pool**. `Enter a label under the zone, such as api or eu.api, or @ for the apex.` : Enter the hostname relative to the zone, without the domain: `api` for `api.example.com`. `Add a pool to the country rule for DE.` : Every rule needs at least one pool. Select one in the rule, or remove the rule. `Load balancer limit reached (50)` or `Steering entry limit reached (200)` : A zone holds up to 50 load balancers, and a load balancer up to 200 pool entries across its default pools and rules. The preview shows `No answer · no members` : No pool in the order has an enabled origin of the type you asked for. An `AAAA` query needs IPv6 origins. The preview shows `No answer · load balancer disabled` : The load balancer is off. Turn it on in the table. The page warns `Proximity steering needs a location on every pool` : A pool without a **Primary location** cannot be ranked by distance, so it answers only when no closer pool can. Set one on each pool. ## Related - [How DNS load balancing works](/websites/load-balancing/) - [Create an origin pool](/websites/load-balancing/create-an-origin-pool/) - [Load balancing reference](/websites/load-balancing/reference/) ## With the API Create a load balancer in zone `42` from pools `7` and `8`, with pool `9` as the fallback. `hostname` is relative to the zone, and the default pools are tried in the order you list them: ```bash curl -X POST https://api.coritan.com/api/v1/dns/zones/42/load-balancers \ -H "Authorization: Bearer $CORITAN_TOKEN" \ -H "Content-Type: application/json" \ -d '{ "name": "api-global", "hostname": "api", "ttl": 30, "steering_policy": "geo", "location_strategy": "pop", "default_pools": [7, 8], "fallback_pool_id": 9, "region_pools": {"WEU": [7], "ENAM": [8]}, "country_pools": {"DE": [7]} }' ``` The answer is `201` with the load balancer: ```json { "id": 5, "zone_id": 42, "name": "api-global", "hostname": "api", "enabled": true, "ttl": 30, "session_affinity": "none", "steering_policy": "geo", "location_strategy": "pop", "fallback_pool_id": 9, "default_pools": [7, 8], "location_pools": {}, "country_pools": {"DE": [7]}, "region_pools": {"WEU": [7], "ENAM": [8]}, "created_at": "2026-09-25T09:30:00Z", "updated_at": "2026-09-25T09:30:00Z" } ``` Region codes are listed in the [reference](/websites/load-balancing/reference/#region-codes). Country codes are two-letter ISO codes, and PoP codes are the location codes the **From PoP** list shows. List a zone's load balancers with `GET /api/v1/dns/zones/42/load-balancers`, sorted by hostname, and read one with `GET /api/v1/dns/zones/42/load-balancers/5`. `PATCH` changes the fields you send; a list or map you send, such as `default_pools` or `country_pools`, replaces the old one whole. `DELETE` answers `204`. Preview an answer. Send `from_location` with a PoP code, or `from_ip` with a resolver's address, and `qtype`: ```bash curl -X POST https://api.coritan.com/api/v1/dns/zones/42/load-balancers/5/preview \ -H "Authorization: Bearer $CORITAN_TOKEN" \ -H "Content-Type: application/json" \ -d '{"qtype": "A", "from_ip": "198.51.100.53"}' ``` ```json { "load_balancer_id": 5, "hostname": "api", "context": {"location_code": null, "country_code": "DE", "region_code": "WEU", "latitude": null, "longitude": null, "source": "resolver_ip"}, "pool_order": [7], "cascade_hit": "country", "selected_pool_id": 7, "member": {"id": 31, "pool_id": 7, "address": "203.0.113.10", "address_type": "A", "weight": 10, "priority": 0, "enabled": true, "health_status": "healthy"}, "servfail": false, "reason": "ok" } ``` `member` is the origin chosen, with the fields of an origin in its pool (the example leaves some out), or `null` when there is no answer. The [reference](/websites/load-balancing/reference/#preview-results) lists the values of `cascade_hit` and `reason`. ## API - `GET /api/v1/dns/zones/{zone_id}/load-balancers`: List load balancers (https://docs.coritan.com/api/reference/client/dns/#op-get-api-v1-dns-zones-zone-id-load-balancers) - `POST /api/v1/dns/zones/{zone_id}/load-balancers`: Create load balancer (https://docs.coritan.com/api/reference/client/dns/#op-post-api-v1-dns-zones-zone-id-load-balancers) - `GET /api/v1/dns/zones/{zone_id}/load-balancers/{lb_id}`: Get load balancer (https://docs.coritan.com/api/reference/client/dns/#op-get-api-v1-dns-zones-zone-id-load-balancers-lb-id) - `PATCH /api/v1/dns/zones/{zone_id}/load-balancers/{lb_id}`: Update load balancer (https://docs.coritan.com/api/reference/client/dns/#op-patch-api-v1-dns-zones-zone-id-load-balancers-lb-id) - `DELETE /api/v1/dns/zones/{zone_id}/load-balancers/{lb_id}`: Delete load balancer (https://docs.coritan.com/api/reference/client/dns/#op-delete-api-v1-dns-zones-zone-id-load-balancers-lb-id) - `POST /api/v1/dns/zones/{zone_id}/load-balancers/{lb_id}/preview`: Preview load balancer (https://docs.coritan.com/api/reference/client/dns/#op-post-api-v1-dns-zones-zone-id-load-balancers-lb-id-preview)