Reason
The most robust means of employing a cluster of multiple Adobe Connect Enterprise servers is with a hardware-based load-balancing device (HLD). This article offers a best-practice configuration of a Connect Server pool or cluster running the full suite of Connect Enterprise server applications: Adobe Acrobat Connect Professional, Adobe Presenter, Adobe Connect Training, and Adobe Connect Events behind a high-end, application-aware HLD such as F5 BIG-IP. This article does not exhaust the possible configurations, but offers a general working example.
Configuring DNS and port assignments
The best place to start is with a basic network diagram illustrating the desired end state of a Connect Enterprise server pool running behind a high end hardware-based load-balancing device (HLD), shown in Figure 1.
Figure 1: Adobe Connect Enterprise server pool running Adobe Acrobat Connect Professional.
Following the example in Figure 1, the virtual Internet protocol addresses (VIPs) on the HLD and the Adobe Connect Enterprise and Acrobat Connect Professional pools correspond in the following manner:
- HTTP VIP: connect.adobe.com: 10.10.10.1:80 points to Connect Enterprise servers: 192.168.0.1: 80 & 192.168.0.2: 80
- RTMP VIP: meeting1.adobe.com: 10.10.10.2:1935 points to Acrobat Connect Professional server meeting1 192.168.0.1: 1935
- RTMP VIP: meeting2.adobe.com: 10.10.10.3:1935 points to Acrobat Connect Professional server meeting2 192.168.0.2: 1935
This configuration can be confusing; it may seem odd to have a single server in a server pool, but each Acrobat Connect Professional VIP on the HLD must point to a single Professional meeting server; it is a one-to-one correspondence. The HTTP enterprise or application VIP is more conventional; it points toward a two-server Connect Enterprise pool; the HTTP application pool handles failover for the RTMP meetings. Resist any temptation to attempt using a single VIP with multiple open ports. Each VIP also needs its own unique fully qualified domain name (FQDN); the configuration above requires three unique FQDNs.
- One unique FQDN for the HTTP VIP: connect.adobe.com
- One unique FQDN for RTMP VIP: meeting1.adobe.com
- One unique FQDN for RTMP VIP: meeting2.adobe.com
The external names for each server are the VIP names: meeting1.adobe.com and meeting2.adobe.com respectively; the host name is connect.adobe.com. The only host name suffix the end users will ever see is connect.adobe.com. Still, three unique FQDNs are required on the HLD: one for each VIP pointing to each Professional meeting/RTMP server and one for both of the Enterprise/HTTP servers. From the perspective of the HLD/SSL accelerator, there are actually four servers in three pools: two Connect Enterprise application servers (connect.adobe.com) in one pool and two Acrobat Connect Professional meeting servers (meeting1.adobe.com and meeting2.adobe.com) each in a pool of its own with its own corresponding VIP. An application-level health monitor on the HLD accelerator should be associated with the HTTP VIP because the Connect Enterprise server will handle load balancing and failover of the meetings on the Acrobat Connect Professional servers (RTMP) while the HLD handles failover of HTTP.
This configuration employs a single IP address on each Connect server. The single IP address uses two ports: 80 for the Connect Enterprise server and 1935 for the Acrobat Connect Professional server.
Configuring the Adobe Connect server pool
The next step is to properly edit the Connect Enterprise server settings to match the VIP configuration on the HLD. Select Start > All Programs > Adobe Connect Enterprise Server > Configure Adobe Connect Enterprise Server > Server Settings to open the server settings in your browser (see Figure 2).
Figure 2: Editing the Adobe Connect Enterprise server settings.
The server settings depicted in Figure 2 correspond with this working example. Add the corresponding external names to match the FQDN of the Meeting VIPs on the HLD.
After your server settings are configured, stop the Adobe Connect services beginning with the Adobe Connect Enterprise Service, followed by the Flash Management Server (FMS) service on each Windows server in the pool (see Figure 3). If the HLD accelerator is properly configured, you will be able to browse the Adobe Connect server pool through the HLD accelerator after restarting the services.
Figure 3: Stopping and restarting the Adobe Connect Enterprise services.
Configuring application-level health monitors on the HLD/SSL accelerator
In order to make sure that the HLD/SSL accelerator performs failover in case one of the application servers should hang, you will want to make certain that the VIP that points to the application server pool is configured with an application level health monitor. If you simply probe the health of the Connect Enterprise servers with a default health monitor at the level of the IP stack, then there are potential cases when the HLD might send traffic to a server with a non-responsive application that seems alive to lower-level probing mechanisms such as the packet Internet groper (PING). Always set the health monitor to probe for an actual string of content on the Connect Enterprise server; all high-end HLDs offer application-level health monitoring. It may not always be intuitive how to configure the monitor because each HLD has a different interface and different means of probing an application, but the following guidance will help you get an appropriate monitor in place.
Consider that you have three server pools and three VIPs. The only VIP and pool combination that needs an application-level health monitor for failover is the enterprise/application HTTP server VIP and pool:
- HTTP VIP: connect.adobe.com: 10.10.10.1:80 points to Connect Enterprise servers: 192.168.0.1: 80 and 192.168.0.2: 80
The probe or health monitor should point to a string on each Connect Enterprise server in its pool to check the health of each server. If one of the servers in the pool becomes non-responsive, the monitor will mark the server down and the HLD will redirect all traffic to the remaining server.
The Acrobat Connect Professional server VIP/pool combinations do not need a health monitor because the Connect Enterprise server handles failover for the Professional Meeting rooms:
- RTMP VIP: meeting1.adobe.com: 10.10.10.2:1935 points to Acrobat Connect Professional server meeting1 192.168.0.1: 1935
- RTMP VIP: meeting2.adobe.com: 10.10.10.3:1935 points to Acrobat Connect Professional server meeting2 192.168.0.2: 1935
Because there is only one server in each pool, there is no place for the HLD to redirect meeting traffic should one of the Acrobat Connect Professional meeting servers fail to respond. The only reason to probe the Acrobat Connect Professional meeting server VIP/pools combination might be to trigger an e-mail message to an administrator to warn that one of the meeting servers is problematic.
The best string on the servers that you may point your application-level health monitor to is the testbuilder diagnostic page:
/servlet/testbuilder
The testbuilder page will send back the "status-ok" string.
It is best to point the health monitor to the testbuilder page rather than a simple HTML string, because testbuilder is actually probing the Connect Enterprise database to make sure there is a healthy connection. If there is any problem with the Connect Enterprise server application, then testbuilder will not report the "status-ok" string.
Each HLD has a different interface to configure these monitors and each one does the check differently. The following example works with F5 BIG-IP against testbuilder:
/servlet/testbuilder HTTP/1.0\n "status-ok"
If you have a problem getting a health monitor to work against testbuilder on your specific HLD, then there is another, less effective option. You can place an HTML file in the content directory on each Connect Enterprise server and point to that file. This option should only be used if testbuilder is problematic with your flavor of HLD. The following example shows an HTML file called healthmonitortarget.html containing the string "You are being served HTML:
common/healthmonitortarget.html HTTP/1.0\nYou are being served HTML
Conclusion
The need for redundancy, availability, and scalability is addressed by clustering Connect Enterprise servers. Although it is possible to use a software-based clustering solution, the most robust solution is to use a high-end HLD. The configuration described in this article is robust.
Where to go from here
Now that you have successfully configured a Connect Enterprise server pool to run behind an HLD, you may want to begin planning to incorporate Adobe Connect Edge Server clusters into your enterprise infrastructure; the Adobe Connect application suite is contagious; as your usage of it ramps up, you may find concentrations of users who could benefit from a local Connect Edge server. When your staff discovers how simple it is to collaborate through Acrobat Connect Professional meetings and how Adobe Presenter and Connect Training can convert a plethora of content into fully deployed presentations, courses, and curricula, you may find that further expansion is warranted. Watch for future Adobe Connect resource center articles describing how to integrate Connect Edge servers with HLDs and Connect Enterprise server clusters.
Sign in to your account