Understanding the FAS cluster address

The cluster address is a single address that targets the FAS cluster. By default this is the value that FCSDK will use as the external address for signalling in outbound sip messages to populate Contact and Record-Route headers, directing subsequent sip messages back to the correct cluster. Because of this the cluster address must be either a DNS resolvable FQDN targeting one or more load balancers in the cluster or a Virtual IP address targeting a load balancer cluster or single load balancer.

Example SIP Headers.

Contact: <sip: 1001@cluster.address:<port>>

Record-Route: <sip: 1001@cluster.address>

Setting the cluster address.

The cluster address is set during the installation of FAS on line 144 of the as-installer-X.X.X.advanced-installer.properties in the Master Node Configuration section.

Setting this to a FQDN such as cluster.example.com will result in the following sip headers:

Contact: “User” <sip:user@cluster.example.com:5060>

Setting this as an IP address would result in the following sip headers:

Contact: “User” <sip:user@192.168.1.1:5060>

Problems with cluster address.

If the cluster address is set incorrectly it will cause an error with routing outgoing SIP messages. These errors will likely appear in the console as:

Errors will also show in the calls.log file (found in /opt/cafex/FAS-X.X.X/domain/servers/appserver/log) you can also see a 5XX error linked to this problem indicating the contact address cannot be resolved using DNS as a FQDN has not been used.

SIP/2.0 500 Contact in INVITE cannot be resolved

Resolving Issues with the cluster address.

To resolve these issues there are three main options.

1. Changing the SIP and HTTP External Address Modes

Firstly in instances where only one load balancer is in use the cluster address can be changed to the IP of the load balancer:

1. Launch the Management Console (https://<FAS>:9990).
2. Select Profiles from the top-right menu.
3. Select the ha profile.
4. Expand Sip and select Sip Servlet.
5. Select the Configuration tab.
6. Click Edit.
7. In the HTTP External Address Mode and SIP External Address Mode drop-down lists, select load-balancer.
8. Click Save.
9. Restart FAS via service fas restart
10. Restart the Media Broker via service fusion_media_broker restart
11. Test a SIP call

This will change the 'Contact' address in outbound sip INVITE messages from the hostname, to the machines IP address.

i.e. from: "Contact: “User” <sip:user@cluster.address:5060>" to "Contact: “User” <sip:user@192.168.1.1:5060>"

You may be required to re-accept the HTTPS certificates on your browser depending on your setup.

For more information on the External Address mode please see the FAS Architecture Guide v2.5, External address mode section on page 17.

 2. Reinstallation of FAS

Secondly, if more than one load balancers are in use a reinstall of the FAS server is the suggested route.

1) Stop the FAS and media broker services using:

 # service fas stop

# service fusion_media_broker stop

2) Check for any remaining running process to confirm fas server and media broker is stopped using

# ps -fC |grep java

3) Move the current installation to a backup location

# mv /opt/cafex/FAS-X.X.X /opt/cafexOld/FAS-X.X.X

4) Now reinstall your FAS server as per FAS Installation Guide Silent Install section, ensuring the entry in as-installer-X.X.X.advanced-install.properties for cluster address is set to a FQDN or IP. e.g.

5) Check the status of FAS and FCSDK server through command

# service fas status

# service fusion_media_broker status

 3. Changing the cluster address - Not Recommended.

Finally, the cluster address can be changed. This is not the suggested route as it will normally require changes to ensure the trust subsystem contains valid identity certificates. Where possible we would recommend following reinstalling FAS (as per instructions above) instead of changing the cluster address.

To change the cluster address using the Management Console

1. Launch the Management Console.
2. Select Profiles from the top-right menu.
3. Select the ha profile.
4. Expand Sip and select Sip Servlet.
5. Select the Configuration tab.
6. Click Edit.
7. In the Cluster Address field, enter the new address.
8. Click Save.

Please see FAS Administration Guide v2.5, Changing the cluster address on page 54.