# Load Balancers

## Prerequisites

The *{config}* API parameter is discussed [here](https://waap.docs.link11.com/using-the-product/the-link11-waap-api/internal-data-structures#the-fundamental-data-structure-configuration).

Load balancer administration is discussed [here](https://waap.docs.link11.com/console-walkthrough/sites/ssl/load-balancers). The discussion below assumes familiarity with it.

## Special considerations when using the API

### Multi-regional configuration

As explained [here](https://waap.docs.link11.com/console-walkthrough/sites/ssl/load-balancers#configuring-traffic-routing), when a Link11 load balancer supports a multi-regional planet, admins can (if desired) configure traffic routing.

The API provides additional granularity beyond the configuration available in the web console: 

* In the UI, the load balancer is treated as a single instance. However, this "one" load balancer is conceptual: it represents multiple physical instances, running simultaneously in different cities. The API provides the ability to configure each city separately, if desired.
* In the UI, the *Preferred datacenter* control displays a list of datacenters where Link11 WAAP has been deployed. In the API, this list is provided in the `upstream_regions` parameter, which is returned when calling *GET /api/v4.3/conf/{config}/load-balancers/regions.*
* In the UI, one *Preferred datacenter* can be selected, which will be applied to all cities. In the API, different datacenters can be specified for different cities, by calling *POST /api/v4.3/conf/{config}/load-balancers/regions.*

{% hint style="info" %}
When calling *POST /api/v4.3/conf/{config}/load-balancers/regions*, all desired preferences should be specified. All unspecified regions will be set to the default preference of `automatic` .

If an incorrect preferred datacenter (one where L11WAAP is not running) is specified, this action will be rejected, and the previous selection will remain in effect.
{% endhint %}

## API overview

<table><thead><tr><th width="346.4755859375">Action</th><th>Operation</th></tr></thead><tbody><tr><td>To retrieve information about all load balancers</td><td>GET .../load-balancers</td></tr><tr><td>To add a certificate</td><td>PUT .../{entry_name}/certificates/{certificate_id}</td></tr><tr><td>To remove a certificate</td><td>DELETE .../{entry_name}/certificates</td></tr><tr><td>To get the list of Link11 WAAP datacenters, and each city's current preference</td><td>GET .../regions</td></tr><tr><td>To set preferred datacenters for each city</td><td>POST .../regions</td></tr></tbody></table>

## Operations

## Get Load Balancers

> Get all Load Balancers in a configuration

```json
{"openapi":"3.0.2","info":{"title":"Link11 WAAP","version":"v4.3"},"paths":{"/api/v4.3/conf/{config}/load-balancers":{"get":{"operationId":"get_load_balancers_api_v3_reblaze_config_load_balancers__get_191271472328453064","summary":"Get Load Balancers","description":"Get all Load Balancers in a configuration","parameters":[{"in":"path","name":"config","required":true,"schema":{"title":"Config","type":"string"}}],"responses":{"200":{"content":{"application/json":{"schema":{"title":"Response Get Load Balancers Api v4.3 Reblaze Load Balancers","properties":{"total":{"type":"integer"},"items":{"type":"array","items":{"$ref":"#/components/schemas/LoadBalancer"}}}}}},"description":"Load Balancers retrieved successfully"},"400":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/InputError"}}},"description":"Input Error"},"500":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/Error"}}},"description":"Internal Server Error"}},"tags":["Load Balancers"]}}},"components":{"schemas":{"LoadBalancer":{"properties":{"certificates":{"items":{"type":"string"},"title":"Certificates","type":"array"},"default_certificate":{"title":"Default Certificate","type":"string"},"dns_name":{"title":"Dns Name","type":"string"},"listener_name":{"title":"Listener Name","type":"string"},"listener_port":{"description":"Port in AWS or IP in GCP","title":"Listener Port","type":"integer"},"load_balancer_type":{"enum":["classic","application"],"title":"Load Balancer Type","type":"string"},"max_certificates":{"title":"Max Certificates","type":"integer"},"name":{"title":"Name","type":"string"},"provider":{"$ref":"#/components/schemas/CloudProviderEnum"},"region":{"title":"Region","type":"string"}},"required":["provider","name","listener_name","listener_port","dns_name","region","load_balancer_type","max_certificates","default_certificate","certificates"],"title":"LoadBalancer","type":"object"},"CloudProviderEnum":{"description":"An enumeration.","enum":["aws","gcp","link11"],"title":"CloudProviderEnum","type":"string"},"InputError":{"properties":{"code":{"title":"Code","type":"integer"},"message":{"title":"Message","type":"string"}},"required":["code","message"],"title":"InputError","type":"object"},"Error":{"properties":{"code":{"title":"Code","type":"integer"},"message":{"title":"Message","type":"string"}},"required":["code","message"],"title":"Error","type":"object"}}}}
```

## Add Certificate

> Add a certificate to a Load Balancer

```json
{"openapi":"3.0.2","info":{"title":"Link11 WAAP","version":"v4.3"},"paths":{"/api/v4.3/conf/{config}/load-balancers/{entry_name}/certificates/{certificate_id}":{"put":{"operationId":"add_certificate_to_load_balancer_api_v3_reblaze_config__config__load_balancers__load_balancer_name__certificates__certificate_id___put_162012920830018407","summary":"Add Certificate","description":"Add a certificate to a Load Balancer","parameters":[{"in":"path","name":"config","required":true,"schema":{"title":"Config","type":"string"}},{"in":"path","name":"entry_name","required":true,"schema":{"title":"Load Balancer Name","type":"string"}},{"in":"path","name":"certificate_id","required":true,"schema":{"title":"Certificate ID","type":"string"}},{"in":"query","name":"provider","required":true,"schema":{"$ref":"#/components/schemas/CloudProviderEnum"}},{"in":"query","name":"region","required":true,"schema":{"title":"Region","type":"string"}},{"in":"query","name":"default","required":false,"schema":{"default":false,"title":"Default","type":"boolean"}},{"in":"query","name":"elbv2","required":false,"schema":{"default":true,"title":"ELB v2","type":"boolean"}},{"in":"query","name":"listener","required":true,"schema":{"title":"Listener","type":"string"}},{"in":"query","name":"listener-port","required":true,"schema":{"title":"Listener Port","type":"integer"}}],"responses":{"200":{"description":"Successfully added certificate to Load Balancer"},"422":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/HTTPValidationError"}}},"description":"Validation Error"},"500":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/Error"}}},"description":"Internal Server Error"}},"tags":["Load Balancers"]}}},"components":{"schemas":{"CloudProviderEnum":{"description":"An enumeration.","enum":["aws","gcp","link11"],"title":"CloudProviderEnum","type":"string"},"HTTPValidationError":{"properties":{"detail":{"items":{"$ref":"#/components/schemas/ValidationError"},"title":"Detail","type":"array"}},"title":"HTTPValidationError","type":"object"},"ValidationError":{"properties":{"loc":{"items":{"anyOf":[{"type":"string"},{"type":"integer"}]},"title":"Location","type":"array"},"msg":{"title":"Message","type":"string"},"type":{"title":"Error Type","type":"string"}},"required":["loc","msg","type"],"title":"ValidationError","type":"object"},"Error":{"properties":{"code":{"title":"Code","type":"integer"},"message":{"title":"Message","type":"string"}},"required":["code","message"],"title":"Error","type":"object"}}}}
```

## Detach certificate

> Detach a non-default certificate from the Load Balancer

```json
{"openapi":"3.0.2","info":{"title":"Link11 WAAP","version":"v4.3"},"paths":{"/api/v4.3/conf/{config}/load-balancers/{entry_name}/certificates":{"delete":{"operationId":"remove_certificate_from_load_balancer_api_v3_reblaze_config__config__load_balancers__load_balancer_name__certificates__delete_1218194429487707258","summary":"Detach certificate","description":"Detach a non-default certificate from the Load Balancer","parameters":[{"in":"path","name":"config","required":true,"schema":{"title":"Config","type":"string"}},{"in":"path","name":"entry_name","required":true,"schema":{"title":"Load Balancer Name","type":"string"}},{"in":"query","name":"provider","required":true,"schema":{"title":"Provider","type":"string"}},{"in":"query","name":"region","required":true,"schema":{"title":"Region","type":"string"}},{"in":"query","name":"certificate-id","required":false,"schema":{"title":"Certificate ID","type":"string"}},{"in":"query","name":"elbv2","required":false,"schema":{"default":true,"title":"ELB v2","type":"boolean"}},{"in":"query","name":"listener","required":false,"schema":{"title":"Listener","type":"string"}},{"in":"query","name":"listener-port","required":false,"schema":{"title":"Listener Port","type":"string"}}],"responses":{"200":{"description":"Successfully detached certificate from Load Balancer"},"422":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/HTTPValidationError"}}},"description":"Validation Error"},"500":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/Error"}}},"description":"Internal Server Error"}},"tags":["Load Balancers"]}}},"components":{"schemas":{"HTTPValidationError":{"properties":{"detail":{"items":{"$ref":"#/components/schemas/ValidationError"},"title":"Detail","type":"array"}},"title":"HTTPValidationError","type":"object"},"ValidationError":{"properties":{"loc":{"items":{"anyOf":[{"type":"string"},{"type":"integer"}]},"title":"Location","type":"array"},"msg":{"title":"Message","type":"string"},"type":{"title":"Error Type","type":"string"}},"required":["loc","msg","type"],"title":"ValidationError","type":"object"},"Error":{"properties":{"code":{"title":"Code","type":"integer"},"message":{"title":"Message","type":"string"}},"required":["code","message"],"title":"Error","type":"object"}}}}
```

## Get available datacenters per region and Load Balancer

> Get regions with available datacenters for each Load Balancer.

```json
{"openapi":"3.0.2","info":{"title":"Link11 WAAP","version":"v4.3"},"paths":{"/api/v4.3/conf/{config}/load-balancers/regions":{"get":{"operationId":"get_load_balancers_regions_api_v4_config_load_balancers__get","summary":"Get available datacenters per region and Load Balancer","description":"Get regions with available datacenters for each Load Balancer.","parameters":[{"in":"path","name":"config","required":true,"schema":{"title":"Config","type":"string"}}],"responses":{"200":{"content":{"application/json":{"schema":{"title":"Response Get Datacenters Regions Api v4.3 Reblaze Load Balancers","$ref":"#/components/schemas/LoadBalancerRegions"}}},"description":"Load Balancers retrieved successfully"},"400":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/InputError"}}},"description":"Input Error"},"500":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/Error"}}},"description":"Internal Server Error"}},"tags":["Load Balancers"]}}},"components":{"schemas":{"LoadBalancerRegions":{"properties":{"city_codes":{"items":{"type":"string"},"title":"City Names","type":"object"},"lbs":{"title":"Load Balancers","type":"array","items":{"$ref":"#/components/schemas/LoadBalancerRegion"}}},"required":["provider","name"],"type":"object"},"LoadBalancerRegion":{"properties":{"id":{"type":"integer","title":"LoadBalancer ID"},"regions":{"type":"object","title":"Current LoadBalancer Settings","items":{"type":"string"}},"name":{"type":"string","title":"LoadBalancer Name"},"upstream_regions":{"type":"array","title":"Available Datacenter Regions","items":{"type":"string"}}}},"InputError":{"properties":{"code":{"title":"Code","type":"integer"},"message":{"title":"Message","type":"string"}},"required":["code","message"],"title":"InputError","type":"object"},"Error":{"properties":{"code":{"title":"Code","type":"integer"},"message":{"title":"Message","type":"string"}},"required":["code","message"],"title":"Error","type":"object"}}}}
```

## Set preferred datacenters for each Load Balancer

> Set preferred datacenters for each Load Balancer. "automatic" will choose the best route depending on the load balancer location.

```json
{"openapi":"3.0.2","info":{"title":"Link11 WAAP","version":"v4.3"},"paths":{"/api/v4.3/conf/{config}/load-balancers/regions":{"post":{"operationId":"set_load_balancers_regions_api_v4_config_load_balancers__set","summary":"Set preferred datacenters for each Load Balancer","description":"Set preferred datacenters for each Load Balancer. \"automatic\" will choose the best route depending on the load balancer location.","parameters":[{"in":"path","name":"config","required":true,"schema":{"title":"Config","type":"string"}}],"requestBody":{"content":{"application/json":{"schema":{"title":"LoadBalancers by ID, with LoadBalancer Region to Datacenter Region","properties":{"lbs":{"title":"LoadBalancers by ID","type":"array","items":{"type":"object","title":"LoadBalancer Region to Datacenter Region"}}},"required":["lbs"]}}}},"responses":{"200":{"content":{"application/json":{"schema":{"title":"Set Preferred Datacenters for each Load Balancers v4.3 Reblaze Load Balancers","properties":{"message":{"type":"string","title":"Message"}}}}},"description":"Load Balancers retrieved successfully"},"400":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/InputError"}}},"description":"Input Error"},"500":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/Error"}}},"description":"Internal Server Error"}},"tags":["Load Balancers"]}}},"components":{"schemas":{"InputError":{"properties":{"code":{"title":"Code","type":"integer"},"message":{"title":"Message","type":"string"}},"required":["code","message"],"title":"InputError","type":"object"},"Error":{"properties":{"code":{"title":"Code","type":"integer"},"message":{"title":"Message","type":"string"}},"required":["code","message"],"title":"Error","type":"object"}}}}
```