As DNS admin it is useful to know how to both view and clear the cache of a Bind server. This can be for a number of reasons but for me its often down to slow DNS lookup, which leads to a sluggish web experience. This is often caused by an issue with the cache,... Continue Reading →
Skipping tags in Puppet
Most people know about the --tags argument to puppet agent execute specific parts of the manifest. '--tags' allows you to specify what portions of a configuration you want to apply. Puppet elements are tagged with all of the class or definition names that contain them, and you can use the 'tags' flag to specify one... Continue Reading →
Diff'ing Cisco IOS Startup-config and running-config
How many times have you needed to know what you are about to commit to your startup-config. The following should help you work out if you are storing what you think you are, or at least show you whats changed from your startup config. show archive config differences If there is nothing pending you will... Continue Reading →
Adding / Removing Secondary IP Cisco IOS
There are many reasons to add additional IPs to an interface, you can use the commands below as an example of how to achieve this. en router# configure terminal router(config)#interface gigabitEthernet 0/2 router(config-if)#ip address 10.10.10.10 255.255.255.0 secondary router(config-if)#end To remove it you simply use the 'no' expression. Using the full command you used to add... Continue Reading →
Importing ISOs to Apache CloudStack
This is something that catches me out every time I build a CloudStack instance (you would think I would know better by now.) You build your cloud and import some ISOs directly from vendor web sites then you remember Oracle Linux is only available via authenticated link. So you drop the ISO onto an internal... Continue Reading →
XenServer Monitoring
Problem: We want to monitor XenServer health in Opsview. Overview: Because installing unapproved software on XenServer / Citrix Hypervisor can impact your support arrangement with Citrix we have to look for other means of monitoring our hypervisor estate. There are a number of options, the one I am going to cover here is for basic... Continue Reading →
WillowSphere 