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I need to add server name in response HTTP headers X-Servedby. Is there any way to replace [server] with name of server that has served request?
frontend front x.x.x.x:80
default_backend balancing
rspadd X-Servedby:\ [server] #I need to replace [server]
backend balancing
server srv1 x.x.x.x:80 check
server srv2 x.x.x.x:80 check
To achieve this, change the frontend stanza to the following:
frontend front x.x.x.x:80
default_backend balancing
acl srv1 srv_id 1
acl srv2 srv_id 2
rspadd X-Servedby:\ srv1 if srv1
rspadd X-Servedby:\ srv2 if srv2
However, a better scaling alternative would be to use cookie in the backend stanza:
backend balancing
cookie SRVNAME insert
server srv1 x.x.x.x:80 cookie srv1 check
server srv2 x.x.x.x:80 cookie srv2 check
Hope this helps!
rspadd X-Servedby:\ srv1 if srv1 is causing error detected while parsing a 'rspadd' condition. I suppose that srv1 in this condition should be defined as ACL, but it seems impossible to define ACL depending on server name. About cookies - this method will cause all requests that have cookie SRVNAME=srv1 to be served by srv1 server isn't it?
We should use srv_id which provides id value defined for server
frontend front x.x.x.x:80
acl serve_us1 url_beg /west
acl serve_us2 url_beg /east
#defining acl for srv_id
acl served_by_us1 srv_id 1 #look at srv_id
acl served_by_us2 srv_id 2 #look at srv_id
use_backend us1 if serve_us1
use_backend us2 if serve_us2
default_backend balancing
rspadd X-ServedBy:\ us1 if served_by_us1
rspadd X-ServedBy:\ us2 if served_by_us2
backend us1
server srv1 1.1.1.1:80 check id 1 #look at id
backend us2
server srv2 2.2.2.2:80 check id 2 #look at id
backend balancing
server srv1 1.1.1.1:80 check id 1 #look at id
server srv2 2.2.2.2:80 check id 2 #look at id