# Helathcheck on multiple backends with virtual hostnames
**URL:** https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413
**Category:** Help!
**Created:** [April 25, 2018, 8:57pm UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413 "2018-04-25T20:57:12Z")
**Posts on this page:** 15
**Page:** 1
### Author:  [@senattcs](https://discourse.haproxy.org/u/senattcs)
#### Post date: [April 25, 2018, 8:57pm UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/1 "2018-04-25T20:57:12Z")
I have 2 backends which are running on two different virtual host names and need to perform healthchecks on them to loadbalance the traffic.
issue is : only the last healthcheck (prd03) works , not prd02. How I can do healthcheck against 2 virtual hostnames?
here is my config:
backend xxxx.searchCustomer
mode http
balance roundrobin
option httpchk GET /env HTTP/1.1\r\nHost:\ [customerlookup.xxx.px-prd02.cf.xxxx.com:443](http://customerlookup.xxx.px-prd02.cf.xxxx.com:443)\r\n
option httpchk GET /env HTTP/1.1\r\nHost:\ [customerlookup.xxx.px-prd03.cf.xxxx.com:443](http://customerlookup.xxx.px-prd03.cf.xxxx.com:443)\r\n
http-check expect rstatus ^200
option httplog
timeout server 60s
default-server inter 10s fall 3 rise 2
server s\_CustomerLookupService.searchCustomer2 [customerlookup.xxx.px-prd02.cf.xxxx.com:443](http://customerlookup.xxx.px-prd02.cf.xxxx.com:443) check resolvers dns ssl verify none
server s\_CustomerLookupService.searchCustomer3 [customerlookup.xxx.px-prd03.cf.xxxx.com:443](http://customerlookup.xxx.px-prd03.cf.xxxx.com:443) check resolvers dns ssl verify none
---
### Author:  [@senattcs](https://discourse.haproxy.org/u/senattcs)
#### Post date: [April 27, 2018, 1:49am UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/2 "2018-04-27T01:49:34Z")
any help please? or point in right direction? basically , I should be able to pass the different hostnames in HK calls
---
### Author:  [@ghp](https://discourse.haproxy.org/u/ghp)
#### Post date: [April 27, 2018, 6:46am UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/3 "2018-04-27T06:46:14Z")
Are you sure “:443” can be part of a hostname?
---
### Author:  [@senattcs](https://discourse.haproxy.org/u/senattcs)
#### Post date: [April 27, 2018, 11:17pm UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/4 "2018-04-27T23:17:25Z")
Yes- we have this working when i have one server in backend server list- but when we added one more server, we are unable to do healthcheck.
---
### Author:  [@txalamar](https://discourse.haproxy.org/u/txalamar)
#### Post date: [April 28, 2018, 9:49am UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/5 "2018-04-28T09:49:06Z")
In my case I have multiple backends (Tomcats) all configured with the same virtual hosts and:
backend app1
option http
…
option httpchk GET /rest/util/setting HTTP/1.0\r\nHost:\ app1.virtualhosttomcat.local:8080\r\n
…
server talaiaclu01-app1 192.168.211.13:8080 cookie server1 maxconn 1000 check inter 5000
server talaiaclu02-app1 192.168.211.14:8080 cookie server2 maxconn 1000 check inter 5000
Behaviour seems to send this check with same header to each server. So in my scenario, different than yours, it’s working. Maybe you can achieve this approache in your scenario.
Reards,
---
### Author:  [@lukastribus](https://discourse.haproxy.org/u/lukastribus)
#### Post date: [April 28, 2018, 12:49pm UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/6 "2018-04-28T12:49:16Z")
It’s a strange requirement to use different Host headers for the backend servers, when they are serving in the same backend and the same services.
How does your customer connect to the backend application, when your backend server requires different Host header and haproxy load-balances?
You could probably workaround this by not health checking in the actual backend but outsource the healthcheck to dedicated backends (with the [track](https://cbonte.github.io/haproxy-dconv/1.7/configuration.html#5.2-track) directive).
---
### Author:  [@senattcs](https://discourse.haproxy.org/u/senattcs)
#### Post date: [April 28, 2018, 10:26pm UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/7 "2018-04-28T22:26:32Z")
My Backend servers are deployed in cloudfoundry and as per cloudfoundry- only way to route traffic to an app is using the virtual hostname:
In Cloud Foundry, a hostname is the label that indicates a subdomain of the domain associated with the route. Given a domain [shared-domain.example.com](http://shared-domain.example.com), a developer can create the route [myapp.shared-domain.example.com](http://myapp.shared-domain.example.com) in space my-space by specifying the hostname myapp with the cf create-route command as shown in this example:
$ cf create-route my-space [shared-domain.example.com](http://shared-domain.example.com) --hostname myapp
Creating route [myapp.shared-domain.example.com](http://myapp.shared-domain.example.com) for org my-org / space my-space as [username@example.com](mailto:username@example.com)…
OK
This command instructs Cloud Foundry to only route requests to apps mapped to this route for the following URLs:
[http://myapp.shared-domain.example.com](http://myapp.shared-domain.example.com)
[https://myapp.shared-domain.example.com](https://myapp.shared-domain.example.com)
Any path under either of the above URLs, such as [http://myapp.shared-domain.example.com/bar](http://myapp.shared-domain.example.com/bar)
@lukastribus- I didn’t understand how to outsource the HK to dedicated backend. would appreciate if you can share a sample.
Thanks in advance.
---
### Author:  [@senattcs](https://discourse.haproxy.org/u/senattcs)
#### Post date: [April 28, 2018, 10:46pm UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/8 "2018-04-28T22:46:42Z")
I think this thread could help my requirement- trying to understand it 🙂
[https://www.mail-archive.com/haproxy@formilux.org/msg17321.html](https://www.mail-archive.com/haproxy@formilux.org/msg17321.html)
---
### Author:  [@ghp](https://discourse.haproxy.org/u/ghp)
#### Post date: [April 30, 2018, 10:25am UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/9 "2018-04-30T10:25:45Z")
Perhaps there can only be one healthcheck per backend, and HAProxy is using the last one you defined. I wonder why, if you have two backends, you don’t define two backends, iso. one backend with two servers.
---
### Author:  [@senattcs](https://discourse.haproxy.org/u/senattcs)
#### Post date: [May 4, 2018, 4:22am UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/10 "2018-05-04T04:22:34Z")
If I create two backends- all my request goto first backend- because I’m routing based on SOAP Action in acl.
Is it really a strange requirement? pivotal Cloudfoundry routes traffic based on virtual hostname and this is a big issue we are facing in production.
---
### Author:  [@ghp](https://discourse.haproxy.org/u/ghp)
#### Post date: [May 4, 2018, 6:35am UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/11 "2018-05-04T06:35:57Z")
> I’m routing based on SOAP Action in acl.
Show that part of your config.
---
### Author:  [@lukastribus](https://discourse.haproxy.org/u/lukastribus)
#### Post date: [May 4, 2018, 6:57am UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/12 "2018-05-04T06:57:44Z")
> [@senattcs](#):
>
> This command instructs Cloud Foundry to only route requests to apps mapped to this route for the following URLs:
>
> [http://myapp.shared-domain.example.com](http://myapp.shared-domain.example.com)
>
> [https://myapp.shared-domain.example.com](https://myapp.shared-domain.example.com)
>
> Any path under either of the above URLs, such as [http://myapp.shared-domain.example.com/bar](http://myapp.shared-domain.example.com/bar)
That I understood. What I do not understand is how you expect your customers host header to be different for one server as opposed to another when haproxy is load balancing to different servers?
More specifically, how is the browser/app-client/customer supposed to send `customerlookup.xxx.px-prd02.cf.xxxx.com:443` for one server and `customerlookup.xxx.px-prd03.cf.xxxx.com:443` for the other?
I’m sure you have a valid use-case, I just not understand it yet.
> [@senattcs](#):
>
> I didn’t understand how to outsource the HK to dedicated backend. would appreciate if you can share a sample.
It would look like this for example:
```
backend check_customerlookup.xxx.px-prd02.cf.xxxx.com
option httpchk GET /env HTTP/1.1\r\nHost:\ customerlookup.xxx.px-prd02.cf.xxxx.com:443\r\n
server prd02 192.168.211.13:8080 cookie server1 maxconn 1000 check inter 5000
backend check_customerlookup.xxx.px-prd03.cf.xxxx.com
option httpchk GET /env HTTP/1.1\r\nHost:\ customerlookup.xxx.px-prd03.cf.xxxx.com:443\r\n
server prd03 192.168.211.14:8080 cookie server1 maxconn 1000 check inter 5000
backend app1
server talaiaclu01-app1 192.168.211.13:8080 cookie server1 maxconn 1000 track check_customerlookup.xxx.px-prd02.cf.xxxx.com/prd02
server talaiaclu02-app1 192.168.211.14:8080 cookie server2 maxconn 1000 track check_customerlookup.xxx.px-prd03.cf.xxxx.com/prd03
```
---
### Author:  [@senattcs](https://discourse.haproxy.org/u/senattcs)
#### Post date: [May 4, 2018, 10:44pm UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/13 "2018-05-04T22:44:37Z")
here is my config , when i have one server in backend.
Clients talk to https://:8003 and if SOAPAction is “searchCustomer”- it will be routed to searchCustomer backend and then routed to server “[customerlookup.xxx.px-prd02.cf.xxxx.com:443](http://customerlookup.xxx.px-prd02.cf.xxxx.com:443)”.
Notice, I’m doing healthcheck using virtual hostname. Now my requirement is to add another server to same backend ([customerlookup.xxx.px-prd02.cf.xxxx.com:443](http://customerlookup.xxx.px-prd02.cf.xxxx.com:443)).
listen http\_frontend
mode http
option http-buffer-request
bind \*:8003 ssl crt /var/prod/data/esp/HAProxy/xxx.pem
acl CustomerLookupService.searchCustomer hdr\_sub(SOAPAction) “searchCustomer”
use\_backend CustomerLookupService.searchCustomer if CustomerLookupService.searchCustomer
backend CustomerLookupService.searchCustomer
mode http
balance roundrobin
option httpchk GET /env HTTP/1.1\r\nHost:\ [customerlookup-xxx.apps.px-prd02.cf.xxx.com:443](http://customerlookup-xxx.apps.px-prd02.cf.xxx.com:443)\r\n
http-check expect rstatus ^200
default-server inter 1s fall 3 rise 1
http-request set-header Host [customerlookup-xxx.apps.px-prd02.cf.xxx.com:443](http://customerlookup-xxx.apps.px-prd02.cf.xxx.com:443)
server s\_CustomerLookupService.searchCustomer2 [customerlookup.xxx.px-prd02.cf.xxxx.com:443](http://customerlookup.xxx.px-prd02.cf.xxxx.com:443) check resolvers dns ssl verify none
---
### Author:  [@lukastribus](https://discourse.haproxy.org/u/lukastribus)
#### Post date: [May 4, 2018, 11:30pm UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/14 "2018-05-04T23:30:49Z")
You didn’t actually respond to my question, but the snippet I shared above already shows how you can achieve healthchecks in this way.
---
### Author:  [@senattcs](https://discourse.haproxy.org/u/senattcs)
#### Post date: [May 5, 2018, 5:18pm UTC](https://discourse.haproxy.org/t/helathcheck-on-multiple-backends-with-virtual-hostnames/2413/15 "2018-05-05T17:18:18Z")
Thank You @lukastribus. Your solution is working for me. Thank you for all the help. here is the latest config, which solved the issue. but I do have a curious question (no complains though!). We can close this issue for now.
Thank you @lukastribus, @ghp and @txalamar for your insights.
1. is there an opportunity to concise this configuration? now for each backend, I have to write two additional healthcheck backends ( and this might go up, if my infra adds another environment). ?
# 68 Opertaion: CustomerLookupService.searchCustomer
```
acl CustomerLookupService.searchCustomer hdr_sub(SOAPAction) "searchCustomer"
use_backend CustomerLookupService.searchCustomer if CustomerLookupService.searchCustomer
```
backend check\_CustomerLookupService.searchCustomer\_02
option httpchk GET /env HTTP/1.1\r\nHost:\ [customerlookup-xxx.apps.px-prd02.cf.xxxx.com:443](http://customerlookup-xxx.apps.px-prd02.cf.xxxx.com:443)\r\n
http-check expect rstatus ^200
default-server inter 1s fall 3 rise 1
http-request set-header Host [customerlookup-xxx.apps.px-prd02.cf.xxx.com:443](http://customerlookup-xxx.apps.px-prd02.cf.xxx.com:443)
server prd02 [customerlookup-xxx.apps.px-prd02.cf.xxxx.com:443](http://customerlookup-xxx.apps.px-prd02.cf.xxxx.com:443) check ssl verify none
backend check\_CustomerLookupService.searchCustomer\_03
option httpchk GET /env HTTP/1.1\r\nHost:\ [customerlookup-xxx.apps.px-prd03.cf.xxxx.com:443](http://customerlookup-xxx.apps.px-prd03.cf.xxxx.com:443)\r\n
http-check expect rstatus ^200
default-server inter 1s fall 3 rise 1
http-request set-header Host [customerlookup-xxx.apps.px-prd03.cf.xxxx.com:443](http://customerlookup-xxx.apps.px-prd03.cf.xxxx.com:443)
server prd03 [customerlookup-xxx.apps.px-prd03.cf.xxxx.com:443](http://customerlookup-xxx.apps.px-prd03.cf.xxxx.com:443) check ssl verify none
backend CustomerLookupService.searchCustomer
mode http
balance roundrobin
default-server inter 1s fall 3 rise 1
option forwardfor
http-send-name-header Host
http-request set-uri /xxx/CustomerLookupService
server [customerlookup-xxx.apps.px-prd02.cf.xxxx.com](http://customerlookup-xxx.apps.px-prd02.cf.xxxx.com) [customerlookup-xxx.apps.px-prd02.cf.xxxx.com:443](http://customerlookup-xxx.apps.px-prd02.cf.xxxx.com:443) track check\_CustomerLookupService.searchCustomer\_02/prd02 ssl verify none
server [customerlookup-xxx.apps.px-prd03.cf.xxxx.com](http://customerlookup-xxx.apps.px-prd03.cf.xxxx.com) [customerlookup-xxx.apps.px-prd03.cf.xxxx.com:443](http://customerlookup-xxx.apps.px-prd03.cf.xxxx.com:443) track check\_CustomerLookupService.searchCustomer\_03/prd03 ssl verify none