Monday, 20 July 2015

iNotes Deployment in HA Mode with Multiple Clusters using Apache Reverse Proxy - Part 2

In continuation to my first post: http://xpagesera.blogspot.in/2013/03/inotes-deployment-in-ha-mode-with.html

In the last post, we tried setting up the Apache Reverse Proxy with Multiple Domino Clusters. Last week, we successfully implemented Apache Reverse Proxy in a unique way:

Cluster size: 7 servers - 6 Mail Servers and 1 Admin Server. This setup ensures that all password changes are immediately available to all Servers.

User's Mail file is available on either Server 1, 3, 5 OR Server 2, 4, 6. In this configuration 4 servers are in DC and 2 servers in DR. We want all traffic to land on Server 1 - 4 (DC). In case none of the DC Servers are available, then it should redirect request to Server 5, 6 (DR).

Instead of relying on the Domino Cluster Information, we have written Rules in Apache httpd.conf file to determine which Load Balancer Group a particular request should be redirected to.

First, the formula used for Apache field in iNotes Web Redirect database:

nodecookievalue:= @Name([CN];@NameLookup([NoUpdate];@UserName;"MailServer"));

clustercookievalue:=@DbLookup("":"";@Subset(@DbName;1):"names.nsf";"($ServersLookup)";nodecookievalue;"clustername");

nodecookie:=@SetHTTPHeader("Set-Cookie";"inotesses="+@LowerCase(nodecookievalue));

@Success

This field will write Cookie values inotesses: Mail Server Name in lowercase.

Second, Check if below modules are present & loaded in Apache Reverse Proxy

LoadModule rewrite_module modules/mod_rewrite.so

LoadModule proxy_module modules/mod_proxy.so

LoadModule proxy_balancer_module modules/mod_proxy_balancer.so

LoadModule proxy_ftp_module modules/mod_proxy_ftp.so

LoadModule proxy_http_module modules/mod_proxy_http.so

LoadModule proxy_ajp_module modules/mod_proxy_ajp.so

LoadModule proxy_connect_module modules/mod_proxy_connect.so

Third, in the httpd.conf file, add Rules to redirect user request to only that server where user's mailfile is present.

<VirtualHost *:443>

ServerName webmail.demo.com

ProxyRequests off

SSLEngine On

SSLProxyEngine On

RewriteEngine On

SSLCertificateFile    /etc/apache2/ssl/webmail.crt

SSLCertificateKeyFile /etc/apache2/ssl/webmail.key

SSLCertificateChainFile /etc/apache2/ssl/chain.crt

ProxyPreserveHost On

<Proxy balancer://Cluster1/>

# loadfactor is added to ensure equal requests are sent to server01 and server02, while server03 will have lowest priority.

BalancerMember https://server01.demo.com:443/ route=server01 loadfactor=50

BalancerMember https://server03.demo.com:443/ route=server03 loadfactor=50

 BalancerMember https://server05.demo.com:443/ route=server03 loadfactor=1

ProxySet lbmethod=byrequests

</Proxy>

<Proxy balancer://Cluster2/>

BalancerMember https://server02.demo.com:443/ route=server02 loadfactor=50

BalancerMember https://server04.demo.com:443/ route=server04 loadfactor=50

 BalancerMember https://server06.demo.com:443/ route=server03 loadfactor=1

ProxySet lbmethod=byrequests

</Proxy>

ProxyPass / balancer://Cluster1/ stickysession=inotesses nofailover=Off

ProxyPassReverse / https://server01.demo.com/

ProxyPassReverse / https://server03.demo.com/

 

ProxyPass / balancer://Cluster2/ stickysession=inotesses nofailover=Off

ProxyPassReverse / https://server02.demo.com/

ProxyPassReverse / https://server04.demo.com/

 

RewriteCond %{HTTP_COOKIE} inotesses=server01 [NC]

RewriteRule ^/((mail|iNotes|icons|domjava)/.*)$ balancer://Cluster1/$1 [P]

 

RewriteCond %{HTTP_COOKIE} inotesses=server02 [NC]

RewriteRule ^/((mail|iNotes|icons|domjava)/.*)$ balancer://Cluster2/$1 [P]

 

RewriteCond %{HTTP_COOKIE} inotesses=server03 [NC]

RewriteRule ^/((mail|iNotes|icons|domjava)/.*)$ balancer://Cluster1/$1 [P]

 

RewriteCond %{HTTP_COOKIE} inotesses=server04 [NC]

RewriteRule ^/((mail|iNotes|icons|domjava)/.*)$ balancer://Cluster2/$1 [P]

</VirtualHost>

 

Now, Stop & start httpd service.