Load Balancing Notes

Quick Setup for Gateway Failsafe

Nicholas Zurfluh — Fri, 03 Feb 2012 17:18:23 +0000

I found this in my notes…

The gateway fail-safe feature allows further redundancy between a failover pair of BIG-IP systems that point to different gateways. The gateway fail-safe feature allows each BIG-IP system to monitor the upstream gateway to which they are connected. If the gateway is marked down, the BIG-IP system can failover to its partner system to prevent further disruption to traffic.

Copy and paste the following commands:

b monitor ICMP_GWFailsafe ‘{

   defaults from gateway_icmp

   interval 2

   timeout 7

}’

b pool gateway_pool_unit1 ‘{

   min up members enable

   min up members 1

   min up members failover

   unit 1

   monitor all ICMP_GWFailsafe

   members x.x.x.x:any {}

}’

b pool gateway_pool_unit2 ‘{

   min up members enable

   min up members 1

   min up members failover

   unit 2

   monitor all ICMP_GWFailsafe

   members x.x.x.x:any {}

}’

Note: Replace x.x.x.x with the IP address of your egress interface of your upstream router.

Save the gateway fail-safe pool configurations by typing the following command:

bigpipe save

Synchronize the configuration between the systems by typing the following command:

bigpipe config sync min

Reload the system configuration by typing the following command:

bigpipe load

To verify that the gateway fail-safe is now enabled, type the following command:

bigpipe ha table

You should see the pool min up member line, which indicates that the gateway fail-safe feature is enabled on the system.

Importing and Exporting Configurations

Nicholas Zurfluh — Fri, 20 Jan 2012 21:34:32 +0000

Starting in, if I recall correctly, version 9.4.3 F5 introduced binary stores for configuration files. For those of us who enjoyed the access of files such as bigip.conf bigip_base.conf this made modifying these files impossible. Here is a technique that will allow you to modify and load both bigip.conf and bigip_base.conf.

If you were not aware /config/bigip.conf was the original configuration file that contains configuration elements that are shared between redundant devices (unit 1 and unit 2).

bigip_base.conf originally contained the configuration elements that are unique to a single device, such as VLANs, self IPs, default route for the management interface, etc…

Here are the commands for loading configuration from the command line:
This command dumps the configuration from memory:

b export filename.ext

This command parses the target file to prove that it is compatible with the running configuration:

b verify load filename.ext

This command saves the newly loaded configuration into the memory resident database:

b save all

This command loads the target file into the running configuration:

b import filename.ext

This command merges the target file into a running configuration without altering existing configuration elements:

b merge filename.ext

Renaming VLANs BIG-IP (LTM)

Nicholas Zurfluh — Fri, 20 Jan 2012 20:53:42 +0000

I find it difficult to rename VLANs or to instruct customers how to rename VLANs for BIG-IP. So in an effort to make it easier I created this script. This intereactive script will replace the name of an existing VLAN with any valid name you choose.

#!/bin/bash

Pause()

{

   key=”"

   echo -n Hit any key to continue…

   stty -icanon

   key=`dd count=1 2>/dev/null`

   stty icanon

}

echo “Enter target VLAN name you wish to change”

read old_VLAN

echo “Enter new replacement VLAN name”

read new_VLAN

echo “Replacing VLAN “${old_VLAN?} “with VLAN “${new_VLAN?}

Pause

b export /var/tmp/bigipconfiguration

sed “s/^vlan $old_VLAN “‘{‘”$/vlan $new_VLAN “‘{‘”/” /var/tmp/newbigipconfiguration.scf

b import /var/tmp/newbigipconfiguration.scf