Manage backends

In your load balancer configuration, a backend defines a pool of servers to load balance.

You can manage backends programmatically by calling the API endpoint /services/haproxy/configuration/backends.

List backends Jump to heading #

To get a list of backends, make a GET request to the backends endpoint:

nix
curl -X GET \
  --user admin:adminpwd \
  "http://127.0.0.1:5555/v2/services/haproxy/configuration/backends"

nix
curl -X GET \
  --user admin:adminpwd \
  "http://127.0.0.1:5555/v2/services/haproxy/configuration/backends"

output
json
{
   "_version":2,
   "data":[{
      "name":"webservers"
   }]
}

output
json
{
   "_version":2,
   "data":[{
      "name":"webservers"
   }]
}

List a specific backend Jump to heading #

To get information about a specific backend, add its name to the end of the URL path. Below, we get information about the backend named webservers:

nix
curl -X GET \
  --user admin:adminpwd \
  "http://127.0.0.1:5555/v2/services/haproxy/configuration/backends/webservers"

nix
curl -X GET \
  --user admin:adminpwd \
  "http://127.0.0.1:5555/v2/services/haproxy/configuration/backends/webservers"

output
json
{
   "_version":3,
   "data":{
      "balance":{
         "algorithm":"roundrobin"
      },
      "default_server":{
         "alpn":"h2",
         "check":"enabled",
         "check_alpn":"h2",
         "maxconn":30,
         "proxy-v2-options":null,
         "weight":100},
         "mode":"http",
         "name":"webservers"
      }
   }
}

output
json
{
   "_version":3,
   "data":{
      "balance":{
         "algorithm":"roundrobin"
      },
      "default_server":{
         "alpn":"h2",
         "check":"enabled",
         "check_alpn":"h2",
         "maxconn":30,
         "proxy-v2-options":null,
         "weight":100},
         "mode":"http",
         "name":"webservers"
      }
   }
}

Add a backend Jump to heading #

To add a backend, make a POST request to the backends endpoint. Send the fields to set in the body of the request. Below, we create a new backend named myservers:

nix
CFGVER=$(curl -s -u admin:adminpwd http://localhost:5555/v2/services/haproxy/configuration/version)
curl -X POST \
  --user admin:adminpwd \
  -H "Content-Type: application/json" \
  -d '{
      "name": "myservers",
      "mode":"http",
      "balance": {
          "algorithm":"roundrobin"
       },
       "default_server": {
           "alpn": "h2",
           "check": "enabled",
           "check_alpn": "h2",
           "maxconn": 30,
           "weight": 100
        }
    }' \
  "http://127.0.0.1:5555/v2/services/haproxy/configuration/backends?version=$CFGVER"

nix
CFGVER=$(curl -s -u admin:adminpwd http://localhost:5555/v2/services/haproxy/configuration/version)
curl -X POST \
  --user admin:adminpwd \
  -H "Content-Type: application/json" \
  -d '{
      "name": "myservers",
      "mode":"http",
      "balance": {
          "algorithm":"roundrobin"
       },
       "default_server": {
           "alpn": "h2",
           "check": "enabled",
           "check_alpn": "h2",
           "maxconn": 30,
           "weight": 100
        }
    }' \
  "http://127.0.0.1:5555/v2/services/haproxy/configuration/backends?version=$CFGVER"

Replace a backend Jump to heading #

To make changes to a backend, you must replace it entirely. To replace an existing backend, make a PUT request to the backends endpoint, passing the name of the backend at the end of the URL path:

nix
CFGVER=$(curl -s -u admin:adminpwd http://localhost:5555/v2/services/haproxy/configuration/version)
curl -X PUT \
  --user admin:adminpwd \
  -H "Content-Type: application/json" \
  -d '{
      "name": "myservers",
      "mode":"http",
      "balance": {
          "algorithm":"roundrobin"
       },
       "default_server": {
           "alpn": "h2",
           "check": "enabled",
           "check_alpn": "h2",
           "maxconn": 30,
           "weight": 50
        }
    }' \
  "http://127.0.0.1:5555/v2/services/haproxy/configuration/backends/myservers?version=$CFGVER"

nix
CFGVER=$(curl -s -u admin:adminpwd http://localhost:5555/v2/services/haproxy/configuration/version)
curl -X PUT \
  --user admin:adminpwd \
  -H "Content-Type: application/json" \
  -d '{
      "name": "myservers",
      "mode":"http",
      "balance": {
          "algorithm":"roundrobin"
       },
       "default_server": {
           "alpn": "h2",
           "check": "enabled",
           "check_alpn": "h2",
           "maxconn": 30,
           "weight": 50
        }
    }' \
  "http://127.0.0.1:5555/v2/services/haproxy/configuration/backends/myservers?version=$CFGVER"

Delete a backend Jump to heading #

To delete a backend, use the DELETE method:

nix
CFGVER=$(curl -s -u admin:adminpwd http://localhost:5555/v2/services/haproxy/configuration/version)
curl -X DELETE \
  --user admin:adminpwd \
  "http://127.0.0.1:5555/v2/services/haproxy/configuration/backends/myservers?version=$CFGVER"

nix
CFGVER=$(curl -s -u admin:adminpwd http://localhost:5555/v2/services/haproxy/configuration/version)
curl -X DELETE \
  --user admin:adminpwd \
  "http://127.0.0.1:5555/v2/services/haproxy/configuration/backends/myservers?version=$CFGVER"