Loadbalancing external mysql cluster nodes

Hi, i have a “design” question.
We have an external mysql cluster with x-nodes. I have configured one external-service in a stack with all ips of the nodes. also i configured service check ( http ) for all nodes. ( this service checks are working correct for each node)

As i want to exchange our hardware loadbalancer cluster as point of failure, i have added a rancher loadbalancer to the stack linked with the external-service mentioned above as only source destination.

a) does loadbalancing over external service works correctly, if all ips configured in on external service ?
b) for testing i have stopped all mysql nodes, but i don´t see in rancher any warning ? must be the stack shown unhealthy ?

my stack config:

version: '2'
services:
  lb-mysql-cluster-2:
    image: rancher/lb-service-haproxy:v0.6.2
    ports:
    - 3307:3307/tcp
    labels:
      io.rancher.container.agent.role: environmentAdmin
      io.rancher.container.create_agent: 'true'
      io.rancher.scheduler.global: 'true'
  lb-mysql-cluster-1:
    image: rancher/lb-service-haproxy:v0.6.2
    ports:
    - 3306:3306/tcp
    labels:
      io.rancher.container.agent.role: environmentAdmin
      io.rancher.container.create_agent: 'true'
      io.rancher.scheduler.global: 'true'
  mysql-cluster-1:
    image: rancher/external-service
  mysql-cluster-2:
    image: rancher/external-service

version: '2’
services:
lb-mysql-cluster-2:
start_on_create: true
lb_config:
certs: []
port_rules:
- priority: 1
protocol: tcp
service: mysql-cluster-2
source_port: 3307
target_port: 3306
health_check:
healthy_threshold: 2
response_timeout: 2000
port: 42
unhealthy_threshold: 3
interval: 2000
lb-mysql-cluster-1:
start_on_create: true
lb_config:
certs: []
port_rules:
- priority: 1
protocol: tcp
service: mysql-cluster-1
source_port: 3306
target_port: 3306
health_check:
response_timeout: 2000
healthy_threshold: 2
port: 42
unhealthy_threshold: 3
interval: 2000
mysql-cluster-1:
external_ips:
- 10.100.0.x1
- 10.100.0.x2
- 10.100.0.x2
- 10.100.0.x3
start_on_create: true
health_check:
response_timeout: 2000
healthy_threshold: 2
port: 9200
unhealthy_threshold: 1
initializing_timeout: 60000
interval: 2000
strategy: recreate
request_line: GET “/” "HTTP/1.0"
reinitializing_timeout: 60000
mysql-cluster-2:
external_ips:
- 10.110.0.x1
- 10.110.0.x2
- 10.110.0.x3
start_on_create: true
health_check:
healthy_threshold: 2
response_timeout: 2000
port: 9200
unhealthy_threshold: 1
initializing_timeout: 60000
interval: 2000
strategy: recreate
request_line: GET “/” "HTTP/1.0"
reinitializing_timeout: 60000