This webcast covers the theoretical introduction to Web Farms and how to build Drupal Web Farms with IIS. Don't miss the second part of the webcast (also part of this series) where a full demo on creating Drupal Web Farms with 4 virtual machines will be presented. If you are already familiar with Web Farms, Application Request Router, Web Farm Framework you can skip to part 2. Otherwise, this webcast is highly recommended and propaedeutic to grasp all the basic knowledge that you might need later.

1. Building Drupal Web
Farms with IIS - Part 1
Alessandro Pilotti
@alexpilotti
MVP ASP.NET / IIS
MCSD, MCAD, MCSE, MCDBA, MCT
Red Hat Certified Engineer

2. Application Request Routing
2.5
 IIS 7.x add-on installable via WebPI or setup available on
http://iis.NET
 Features
 HTTP based routing decisions
 Load balance algorithms
 Health monitoring
 Client affinity
 Host name Affinity
 Multiple server groups
 Managing and monitoring by using the UI
 Caching
 SSL offloading
 Failed Request Tracing rules

3. Web Farm Framework 2.1
 Features
 Integration with ARR
 Platform provisioning
 Including frameworks (PHP, etc)
 Application provisioning via WebDeploy
 Simplified farm management
 Rich UI for monitoring and management

4. Architecture

5. Create a Server Farm
After installing ARR and/or WFF the node “Server
Farms” shows up in the tree

6. Server Farm
 You can enable independently
 Load balancing
 Server farm provisioning
 Enabling server farm provisioning only means that an alternative
load balancing solution is planned, e.g.:
 Hardware NLB
 Varnish
 Apache + HAProxy
 WFF requires administrator credentials valid on all the hosts
belonging to the farm
 Creating an ARR farm via GUI creates also URL rewrite rules

7. Server Farm Details

8. WFF Server Roles
 WFF is based on the concept of a primary host and multiple
secondary hosts
 Primary host
 Is the master
 Platform and applications get provisioned to secondary hosts
 Secondary hosts
 Are “clones” of the primary host
 Roles can be switched
 A secondary host can become primary
 Provisioning is customizable

9. Adding Servers

10. CLI
 To achieve the same result as seen before:
 appcmd.exe set config -section:webFarms /+"[name='myServerFarm']"
/commit:apphost
 appcmd.exe set config -section:webFarms
/+"[name='myServerFarm'].[address=’DrupalWeb1']" /commit:apphost
 URL Rewrite rules:
 appcmd.exe set config -section:system.webServer/rewrite/globalRules
/+"[name='ARR_myServerFarm_loadbalance', patternSyntax='Wildcard',stopProces
sing='True']" /commit:apphost
 appcmd.exe set config -section:system.webServer/rewrite/globalRules
/[name='ARR_myServerFarm_loadbalance',patternSyntax='Wildcard',stopProcessin
g='True'].match.url:"*" /commit:apphost
 appcmd.exe set config -section:system.webServer/rewrite/globalRules
/[name='ARR_myServerFarm_loadbalance',patternSyntax='Wildcard',stopProcessin
g='True'].action.type:"Rewrite"
/[name='ARR_myServerFarm_loadbalance',patternSyntax='Wildcard',stopProcessin
g='True'].action.url:"http://myServerFarm/{R:0}" /commit:apphost

11. ARR Configuration

12. Health Test

13. Load Balance

14. Routing Rules

15. Server Affinity

16. Caching
Primary and secondary disk caches are
configured at the server level

17. Add Drives

18. Cache Configuration

19. Cache Warm-up

20. Cache Rules

21. Enable Caching in the Farm

22. Platform Provisioning

23. Application Provisioning

24. Failed Request Tracing
 Detailed requests log
 Excellent troubleshooting
tool
 Launch IIS Manager
 Select web site
 e.g. Default Web Site
 Select Failed Request
Tracing…

25. Enable Failed Request
Tracing

26. Tracing Rules
 Select Failed Request Tracing Rules in the features
pane
 Add…

27. Trace Conditions

28. Select Providers

29. Analyze Traces
 Traces are located by default in
 %SystemDrive%inetpubLogsFailedReqLogFiles
 Sections to check:
 GENERAL_REQUEST_HEADERS
 ARR_REQUEST_ROUTED
 ARR_SERVER_STATS
 GENERAL_RESPONSE_HEADERS
 GENERAL_RESPONSE_ENTITY_BUFFER

30. CLI
 To obtain what we did via GUI:
 appcmd set site "Default Web Site" -
traceFailedRequestsLogging.enabled:"true" /commit:apphost
 appcmd.exe set config "Default Web Site" -
section:system.webServer/tracing/traceFailedRequests
/+"[path='*']”
 appcmd.exe set config "Default Web Site" -
section:system.webServer/tracing/traceFailedRequests
/+"[path='*'].traceAreas.[provider='WWW
Server',areas='Rewrite,RequestRouting',verbosity='Verbose']”
 appcmd.exe set config "Default Web Site" -
section:system.webServer/tracing/traceFailedRequests
/[path='*'].failureDefinitions.statusCodes:"200-399"

31. Shared Config
 Share the same IIS server configuration among two or
more hosts
 Obtained by saving the configuration files on a network
share
 An encryption key is set to protect sensitive data
 Web sites reside on shared paths

32. Export Config

33. Enable Shared Config

34. Shared Config

35. Scenario

36. Roles
 Load balancer / Farm controller (DrupalARR)
 Web Server 1 (DrupalWeb1)
 Web Server 2 (DrupalWeb2)
 File Server (DrupalFileServer)
 MySQL Server (DrupalDB)
 Note: In our demo and lab, we will install MySQL on DrupalFileServer
to limit the number of required VMs

37. DBMS
 Install MySQL on the DBMS server
 Can be Windows, Linux, etc
 CREATE DATABASE MyNewDrupalSite2;
 Enable access to the MySQL database from the web
servers. E.g.:
 CREATE USER 'MyNewDrupalSite2'@'%' IDENTIFIED BY
'Passw0rd';
 GRANT ALL On MyNewDrupalSite2.* TO
'MyNewDrupalSite2'@'%’;
 Note: in the Drupal web apps, connecting to MySQL using
an IP address is preferred
 Avoid name resolution

38. Web Farm Hosts
 Web farm hosts (DrupalWeb1 and
DrupalWeb2)
 Install Web Deploy via WebPI, if not already
installed
 Disable UAC (User Account Control)
 Enable the following feature through the local
firewall
 Core Networking
 File And Printer Sharing
 Remote Administration

39. Web Farm Hosts
 We need a common account with administrator rights
on the hosts. It can be:
 A domain user
 A user with same username/password on all hosts
 Must be a member of the “Administrators” group
 Check that the user password is not set to expire
 net user wfadmin Passw0rd /add
 wmic path Win32_UserAccount where
Name='wfadmin' set PasswordExpires=false
 net localgroup administrators wfadmin /add

40. Drupal Web Site
 Create a Drupal web site on the primary server
(DrupalWeb1)
 Via WebPI or manually
 As seen in the previous lessons
 Install all necessary components
 PHP 5.3, PHP Manager, WinCache, URL Rewrite
 Point the Drupal DB configuration to the database on the
DBMS server
 For performance reasons, consider using an IP address
instead of name resolution
 WFF will later use WebDeploy to replicate the site to
the secondary servers (DrupalWeb2 in our case)

41. Load Balancer ARR
 Install ARR 2.5 and WFF 2.1 via WebPI

42. ARR
 Open IIS Manager and create Web Farm.
 Note: if IIS Manager was open during the setup of ARR, it
needs to be closed and reopened to be able to access
the installed features.


43. Server Farm Details
 Set the wfadmin user you created in the previous steps

44. Add Primary Host to the Farm
 In our case, DrupalWeb1 will become the primary
server
 This host contains the Drupal web site(s) to be served
by the farm (can be added later)

45. Add Secondary Hosts to the
Farm

46. URL Rewrite Rules
 Create local URL Rewrite rules. This is the base of the
redirection process!

47. Platform Provisioning
 At this point, platform and application synchronization
between the hosts takes place.
 Platform tools and frameworks that are available on the
primary server get installed on the other servers.
 Afterwards, application pools, sites and applications will
be synchronized
 Provisoning can be started manually
 Check secondary web farm hosts afterwards

48. Platform Provisioning

49. ARR – Configure Health Test

50. ARR – Check Health Test

51. ARR – Set Affinity Cookie
Note: a distributed session management should
also be evaluated.

52. The “drupalwp” User
 Create a common user on:
 DrupalFileServer
 DrupalWeb1
 DrupalWeb2
 No privileges required
 net user drupalwp Passw0rd /add
 wmic path Win32_UserAccount where
Name=’drupalwp' set PasswordExpires=false
 Check that the user password is not set to expire
 Repeat on all the above hosts

53. WP Identity
 On the primary server, in IIS Manager, open the server
node, click on Application Pools and on the Drupal web
site application pool.
 Click on “Advanced Settings…”
 Change the Identity to the drupalwp user and set it to
“drupalwp”
 In the PHP.ini configuration file on the PHP version
used by the Drupal web site, set
 fastcgi.impersonate = 0
 For performance, make sure also that WinCache is
enabled.

54. Shared Storage Access
 Drupal requires a shared “files” directory accessed by the
web farm hosts
 Can be hosted on a SMB share
 As an alternative FS sync solutions could be applied
 DFS, rsync, WebDeploy, etc
 A valid user must exist on the web farm hosts and on the file
server. It can be:
 A domain account
 A local user with same username and password
 Proper permissions need to be set on the SMB share

55. Folder Permissions
 Create a directory where you want to store your Drupal
shared data
 E.g: C:DataMyNewDrupalSite
 Add write permissions for the user “drupalwp”

56. SMB Share
 Create an SMB share for the directory and add
read/write permissions for the user “drupalwp”

57. CLI
 md C:DataMyNewDrupalSite
 icacls C:DataMyNewDrupalSite /grant
drupalwp:(OI)(CI)(RX,W)
 net share
MyNewDrupalSite=C:DataMyNewDrupalSite
/grant:wpuser,Change

58. Troubleshoot SMB Access
 From the web farm hosts (DrupalWeb1, DrupalWeb2) try to access
the shared folder with the identity of the WP user:
 Runas /u:drupalwp cmd
 In the drupalwp command prompt:
 net use drupaltest05MyNewDrupalSite
 echo test > drupaltest05MyNewDrupalSitetest.txt
 dir drupaltest05MyNewDrupalSite
 File exists: ok
 del drupaltest05MyNewDrupalSitetest.txt

59. Drupal Configuration
 Log on the drupal web site as administrator and go to:
 Administer -> Site Configuration -> File System
 Set the “File System”, “Temp” path on the shared
storage area.
 Create a separate share on the file server for the “Private”
path if necessary

60. Drupal Configuration

61. Drupal 6 Caveat
 Drupal 6.19 published on WebPI doesn’t support UNC
paths. This can be easily solved with the following code
patch:
File includes/file.inc
Line 126
Original if (!is_writable($directory)) {
Modified if (!touch($directory)) {