GTM - Lingo translated from an LTM perspective (and monitoring)
Dear experts I've set out to find typically good stuff to monitor on the GTM and to do that I had to re-evaluate some terms and things I took for granted from the LTM world. I thought I'd share what I have written down. Hopefully it will help some other poor soul coming from the LTM side to get the grip of the basics. Please do comment if (or actually rather when) I've misunderstood something? A diagram of a basic set-up Lingo Server This is the equivalent of an F5 unit (or a generic server). Data center This is more or less just a container with Servers in them. Data center availability is determined by doing an aggregate checks of virtual server statuses. If all virtual servers are down, the data-center is down, otherwise not. Virtual server These are the classical virtual servers we know from the LTM. Wide IP This is the actual dns record and it's aliases. The wide IP uses a pool containing one or more LTM virtual servers (or, a manually defined fallback server IP). The GTM uses the pool to select the best server based on criteria defined by the admin (GEO-IP based, connections, just plain round-robin, irules etc.). Link A link is a possible path to the internet. In case a GTM is connected to multiple routers it can also use multiple links in case one, or more of the routers is unavailable. If all links are down, the objects monitored via those links also goes down. If no link is specified the GTM would use the configured routing. Listeners This is where the clients would send their DNS queries. You must have at least one in order for GTM to work, but more than one is also possible. Monitoring of virtual servers The GTM would not monitor F5 devices like the LTM monitors its pool members and nodes. Instead it establishes a trust with the devices by running the bigip_add (a bit like device trust) and then the monitoring is done through iQuery. Monitoring In order to get a basic monitoring going I've thought out the following parts. Please let me know if something should be added? Availability: Server availability Data center availability Virtual server availablity Wide IP availability* Link availability Status of iQuery Statistics: Memory, CPU, throughput etc Requests per Wide IP Unhandled requests per Wide IP Total requests per GTM Total unhandled requests per GTM Any comments/feedback very much appreciated!
