HAProxy balancer using the url_param value? - hash

I have 3 different restful servers: w1, w2, w3
My clients that refer to my load balancer are providing the url parameter called "ip" (ipv4). The url parameter ip is different between a requests:
curl -XGET http://localhost:8080/api/v1/link?ip=x.x.x.x
I would like to balance with HAProxy to w1, w2, w3 according to the ip parameter using HASH algo.
HAProxy configuration below:
global
#daemon
maxconn 3000
defaults
mode http
timeout connect 5000ms
timeout client 50000ms
timeout server 50000ms
frontend http-in
bind *:80
default_backend workers
backend workers
balance url_param ip
hash-type consistent
server w1 localhost:8080 weight 1 maxconn 1000 check
server w2 localhost:8081 weight 1 maxconn 1000 check
server w3 localhost:8082 weight 1 maxconn 1000 check
listen admin
bind *:8088
stats hide-version
stats realm HAProxy\ statistics
stats enable
How can I achieve that?

With HAProxy 1.6.4 (and lower versions) choose the source balance algorithm. I think this algorithm should do your job or was there a reason for choosing balance url_param ?
balance source
hash-type consistent
The hash-type is optional but could be useful. Here some further information.

Related

Leaky bucket method with Haproxy - Rate limiting

Nginx uses the leaky bucket method to limit request rate. Nginx http_limit_req_module.
It means that if I set a limit to 100 req/sec, and then I get flooded by 120 req/sec, 100 requests will be served normally but 20 requests will be served by a 503 error.
How can I setup this with Haproxy?
I read a lot of the documentation about sc_http_req_rate but since the rate is always 120 req/sec. I am always returning 503 errors.
frontend main
bind *:80
acl foo_limited_req sc_http_req_rate(0) ge 100
http-request track-sc0 path table Abuse # Set the URI as the key of the table
use_backend bk1 if foo_limited_req
default_backend web
backend web
server web1 192.168.0.10
backend Abuse
stick-table type string len 128 size 100K expire 30m store http_req_rate(1s)
backend bk1
server listenerror 127.0.0.1:81
listen errorlistener
bind 127.0.0.1:81
mode http
errorfile 503 /etc/haproxy/errors/200-tuned.http
I want to serve the flow of 100 req/sec with web backend. And the 20 req/sec surplus with bk1 backend.
Youll want to set the maxconn setting in your global settings to "X", which is your desired rate limit.
See below for an example of mine:
global
log 127.0.0.1 syslog
maxconn 1000
user haproxy
group haproxy
daemon

how to prevent 502 status code as response by haproxy as load balancer

I have 3 server:
server (A)= a nginx(port 80) as reverse proxy to kestler (5000 port)
server (B)= a nginx(port 80) as reverse proxy to kestler (5000 port)
server (C)= a HAProxy as load balancer for port 80 of server (A) and (B)
and server A & B are quite similar.
every things works very well and haproxy forwards requests to server (A) & (B), but if kestrel in one of servers (e.g. A) be killed, nginx respond 502 bad gateway error and haproxy not detect this issue and still redirect requests to it, and this is mistake! it must redirect requests to server (B) in this time.
global
log 127.0.0.1 local2 info
chroot /var/lib/haproxy
stats socket /run/haproxy/admin.sock mode 660 level admin
stats timeout 30s
user haproxy
group haproxy
daemon
defaults
log global
mode http
option httplog
option dontlognull
option redispatch
retries 3
timeout connect 5s
timeout client 50s
timeout server 50s
stats enable
stats hide-version
stats auth admin:admin
stats refresh 10s
stats uri /stat?stats
frontend http_front
bind *:80
mode http
option httpclose
option forwardfor
reqadd X-Forwarded-Proto:\ http
default_backend http_back
backend http_back
balance roundrobin
mode http
cookie SERVERID insert indirect nocache
server ServerA 192.168.1.2:80 check cookie ServerA
server ServerB 192.168.1.3:80 check cookie ServerB
How Can I resolve this issue?
thanks very much.
You are only checking whether nginx is running, not whether the application is healthy enough to use.
In the backend, add option httpchk.
option httpchk GET /some/path HTTP/1.1\r\nHost:\ example.com
Replace some path with a path that will prove whether the application is usable on that server if it returns 200 OK (or any 2xx or 3xx response), and replace example.com with the HTTP Host header the application expects.
option httpchk
By default, server health checks only consist in trying to establish a TCP connection. When option httpchk is specified, a complete HTTP request is sent once the TCP connection is established, and responses 2xx and 3xx are
considered valid, while all other ones indicate a server failure, including the lack of any response.
This will mark the server as unhealthy if the app is not healthy, so HAProxy will stop sending traffic to it. You will want to configure a check interval for each server using inter and downinter and fastinter options on each server entey to specify how often HAProxy should perform the check.

modify http response (not header) in haproxy

i want to make one website(lets say blocked.com) that is not accessible from my country to be accessible for my clients throue the custom url like notblocked.com using haproxy.
i have my haproxy box configured on the vps outside of the country. the main problem is,that website sending url redirection on the response body using javascript function and my clients getting redirected to the original web address.
how can i intersept the response body and change the domain name in the java scrip to my domain (notblocked.com) .
haproxy configuration
global
log 127.0.0.1 local0
maxconn 4000
maxsslconn 256
tune.ssl.default-dh-param 2048
daemon
uid 99
gid 99
defaults
log global
mode http
option httplog
option dontlognull
timeout server 5s
timeout connect 5s
timeout client 5s
stats enable
stats refresh 10s
stats uri /stats
frontend https_frontend
bind *:443 ssl crt /etc/ssl/certs/kstore.pem
no option http-server-close
mode http
default_backend web_server
http-request set-header Host blocked.com
backend web_server
mode http
balance roundrobin
server srv01 1.2.3.4:443 weight 1 maxconn 100 check ssl verify none
thanks

How to configure haproxy to use a different backend for each request

I have an Haproxy 1.5.4. I would like to configure the haproxy to use a different backend for each request. This way , I want to ensure that a diffeent backend is used for each request. I curently use the following config:
global
daemon
maxconn 500000
nbproc 2
log 127.0.0.1 local0 info
defaults
mode tcp
timeout connect 50000ms
timeout client 500000ms
timeout server 500000ms
timeout check 5s
timeout tunnel 50000ms
option redispatch
listen httptat *:3310
mode http
stats enable
stats refresh 5s
stats uri /httpstat
stats realm HTTPS proxy stats
stats auth https:xxxxxxxxxxx
listen HTTPS *:5008
mode tcp
#maxconn 50000
balance leastconn
server backend1 xxx.xxx.xxx.xxx:125 check
server backend1 xxx.xxx.xxx.xxx:126 check
server backend1 xxx.xxx.xxx.xxx:127 check
server backend1 xxx.xxx.xxx.xxx:128 check
server backend1 xxx.xxx.xxx.xxx:129 check
server backend1 xxx.xxx.xxx.xxx:130 check
......
simply change the balance setting from leastconn to roundrobin
from the haproxy manual for 1.5 :
roundrobin Each server is used in turns, according to their weights.
This is the smoothest and fairest algorithm when the server's
processing time remains equally distributed. This algorithm
is dynamic, which means that server weights may be adjusted
on the fly for slow starts for instance. It is limited by
design to 4095 active servers per backend. Note that in some
large farms, when a server becomes up after having been down
for a very short time, it may sometimes take a few hundreds
requests for it to be re-integrated into the farm and start
receiving traffic. This is normal, though very rare. It is
indicated here in case you would have the chance to observe
it, so that you don't worry.
https://cbonte.github.io/haproxy-dconv/1.5/configuration.html#4-balance

Can haproxy be configured to understand SSL sessions without being sticky to time

Am using HAProxy version haproxy-1.4.24 on a SLES 11 SP3 server. I need to load balance (using least connections or round robin) between 3 servers which talk only SSL. A session from client to server starts with client/server handshake followed by a series of "chatty" messages and then close of session.
I do not want to use stick src directive since it needs a time limit argument, making my load balancing ineffective.
Below is the configuration file am using. Can someone let me know how to achieve per session stickiness (one client sticks to one server until the SSL session ends)?
global
log /dev/log local0
log /dev/log local1 notice
#chroot /var/lib/haproxy
#stats socket /run/haproxy/admin.sock mode 660 level admin
stats timeout 30s
#user haproxy
#group haproxy
daemon
defaults
log global
mode http
option httplog
option dontlognull
timeout connect 5000
timeout client 50000
timeout server 50000
frontend localnodes
bind *:80
bind *:443
mode tcp
default_backend nodes
backend nodes
mode tcp
balance roundrobin
stick-table type ip size 200k expire 30m
stick on src
server s1 s1.mydomain.com:443 check
server s2 s2.mydomain.com:443 check
server s3 s3.mydomain.com:443 check