Maximum Connections

You can specify the maximum number of concurrent connections through the ingress.appscode.com/max-connections annotation. When applied to ingress, this rule will be applied globally for all backends. To apply for a specific backend, you need to apply the annotation to associated pod.

Ingress Example

First create a test-server and expose it via service:

$ kubectl run test-server --image=gcr.io/google_containers/echoserver:1.8
deployment "test-server" created

$ kubectl expose deployment test-server --type=LoadBalancer --port=80 --target-port=8080
service "test-server" exposed

Then create the ingress:

$ kubectl apply -f test-ingress.yaml

apiVersion: voyager.appscode.com/v1beta1
kind: Ingress
metadata:
  name: test-ingress
  namespace: default
  annotations:
    ingress.appscode.com/max-connections: "1"
spec:
  rules:
  - host: voyager.appscode.test
    http:
      paths:
      - path: /foo
        backend:
          serviceName: test-server
          servicePort: 80

This will add maxconn 1 in global section of generated haproxy.cfg.

Generated haproxy.cfg:

# HAProxy configuration generated by https://github.com/appscode/voyager
# DO NOT EDIT!
global
	daemon
	stats socket /tmp/haproxy
	server-state-file global
	server-state-base /var/state/haproxy/
	maxconn 1
	# log using a syslog socket
	log /dev/log local0 info
	log /dev/log local0 notice
	tune.ssl.default-dh-param 2048
	ssl-default-bind-ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK
defaults
	log global
	# https://cbonte.github.io/haproxy-dconv/1.7/configuration.html#4.2-option%20abortonclose
	# https://github.com/appscode/voyager/pull/403
	option dontlognull
	option http-server-close
	# Timeout values
	timeout client 50s
	timeout client-fin 50s
	timeout connect 50s
	timeout server 50s
	timeout tunnel 50s
	# Configure error files
	# default traffic mode is http
	# mode is overwritten in case of tcp services
	mode http
frontend http-0_0_0_0-80
	bind *:80 
	mode http
	option httplog
	option forwardfor
	acl is_proxy_https hdr(X-Forwarded-Proto) https
	acl acl_voyager.appscode.test hdr(host) -i voyager.appscode.test
	acl acl_voyager.appscode.test hdr(host) -i voyager.appscode.test:80
	acl acl_voyager.appscode.test:foo path_beg /foo
	use_backend test-server.default:80 if acl_voyager.appscode.test acl_voyager.appscode.test:foo
backend test-server.default:80
	server pod-test-server-68ddc845cd-x7dtv 172.17.0.4:80

Pod Annotation

To apply it for specific backend let’s patch the deployment and add the annotation to pod template:

$ kubectl patch deployment test-server -p '{"spec":{"template":{"metadata":{"annotations":{"ingress.appscode.com/max-connections": "3"}}}}}'
deployment "test-server" patched

This will add maxconn 3 in server section of generated haproxy.cfg.

Generated haproxy.cfg:

# HAProxy configuration generated by https://github.com/appscode/voyager
# DO NOT EDIT!
global
	daemon
	stats socket /tmp/haproxy
	server-state-file global
	server-state-base /var/state/haproxy/
	maxconn 1
	# log using a syslog socket
	log /dev/log local0 info
	log /dev/log local0 notice
	tune.ssl.default-dh-param 2048
	ssl-default-bind-ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK
defaults
	log global
	# https://cbonte.github.io/haproxy-dconv/1.7/configuration.html#4.2-option%20abortonclose
	# https://github.com/appscode/voyager/pull/403
	option dontlognull
	option http-server-close
	# Timeout values
	timeout client 50s
	timeout client-fin 50s
	timeout connect 50s
	timeout server 50s
	timeout tunnel 50s
	# Configure error files
	# default traffic mode is http
	# mode is overwritten in case of tcp services
	mode http
frontend http-0_0_0_0-80
	bind *:80 
	mode http
	option httplog
	option forwardfor
	acl is_proxy_https hdr(X-Forwarded-Proto) https
	acl acl_voyager.appscode.test hdr(host) -i voyager.appscode.test
	acl acl_voyager.appscode.test hdr(host) -i voyager.appscode.test:80
	acl acl_voyager.appscode.test:foo path_beg /foo
	use_backend test-server.default:80 if acl_voyager.appscode.test acl_voyager.appscode.test:foo
backend test-server.default:80
	server pod-test-server-77b558b98-8kc2d 172.17.0.4:80  maxconn 3

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