Real-Time Logging for Failed Server Selection

This chapter contains the following topics:


     Using the GUI to Configuring Real-Time Logging

     Using the CLI to Configure Real-Time Logging


ACOS provides real-time notifications for when the system has detected a failed server selection. Log entries include the cause of the event and users are immediately notified of the instance. In addition to the system log entry, you can configure alerts using SNMP traps, enabling you to immediately respond to server selection failure.

To implement this feature, perform the following steps:

1.     Within a server template, enable alerts for failed server selection and apply to the SLB server, if necessary.

2.     Apply the template to one or more real servers.

3.     Add these servers to a service group, and apply the service group to a virtual server.

4.     Configure SNMP traps for immediate event notifications of failed server selection. The SNMP trap notification will include information such as the server name, IP address, server port, partition name, and known cause for server selec­tion failure.

Using the GUI to Configuring Real-Time Logging

Perform the following procedures to configure real-time alerts with the GUI:

     Configure Logging

     Configure SNMP Traps

Configure Logging

To configure logging:

1.     Hover over ADC in the menu bar, then select Templates. The SLB tab should be selected by default; if not, select it.

2.     Click Create and select Server from the drop-down menu.

3.     Enter a name and other basic information for the template. (See the online help for details on mandatory fields.)

4.     Select checkbox in the Log Selection Failure field.

FIGURE 147      ADC > Templates > SLB > Server


This option enables real-time logging for the server selection failure event.

5.     Optionally, modify the template configuration.

6.     Click OK, or click Update if you are modifying an existing template.

Configure SNMP Traps

To configure SNMP traps:

7.     Hover over System in the menu bar, then select Getting Started.

8.     In the SNMP section, click the Edit (Pencil) button.

9.     For System SNMP Service, select the Enable radio button.

10.  In the Trap List section, select the Server Selection Failure trap in the “SLB Group” section.



Using the CLI to Configure Real-Time Logging

Enter the following command to send SNMP traps if server selection fails:

ACOS(config)# snmp-server enable traps slb server-selection-failure


The following example shows the configuration of a server with enabled logging of failed server selection and SNMP notifi­cation alerts.

ACOS(config)# slb template server svtemp1

ACOS(config-rserver)# conn-rate-limit 1

ACOS(config-rserver)# log-selection-failure


Create a server and apply the template with logging enabled for failed server selection.

ACOS(config)# slb server srv266

ACOS(config-real server)# template server svtemp1

ACOS(config-real server)# port 80 tcp


Create a service group and add the srv266 server.

ACOS(config)# slb service-group fail-servers tcp

ACOS(config-slb svc group)# member srv266 80

ACOS(config-slb svc group-member:80)# exit 


Create a virtual server:

ACOS(config)# slb virtual-server fail-233

ACOS(config-slb vserver)# port 80 http

ACOS(config-slb vserver-vport)# name _1.1.1.1_HTTP_80

ACOS(config-slb vserver-vport)# service-group fail-servers

ACOS(config-slb vserver-vport)# exit 


Enable SNMP notifications for failed server selection:

ACOS(config)# snmp-server enable traps slb server-selection-failure

ACOS(config)# snmp-server host version v2c public udp-port 162


The following is an example of show command output after an instance of failed server selection:

ACOS# show log

Log Buffer: 30000

Dec 28 2012 07:09:15 Warning [ACOS]:Server srv266(port:80) selection failure(exceeded_re­al_server_connection_rate_limit)

Dec 28 2012 07:09:15 Warning [ACOS]:Server srv266(port:80) selection failure(exceeded_re­al_server_connection_rate_limit)


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