curl -X POST \
  --user admin:adminpwd \
  -H "Content-Type: application/json" \
  -d '{
    "name": "lololo",
    "mode": "http",
    "balance": {
      "algorithm": "roundrobin"
    },
    "default_server": {
      "alpn": "h2",
      "check": "enabled",
      "check_alpn": "h2",
      "maxconn": 30,
      "weight": 100
    }
  }' \
  "http://192.168.0.200:8080/v3/services/haproxy/configuration/backends?version=$CFGVER"