...
For each command, Shinken knows if it is global or not. If global, it just sends orders to all schedulers. For specific ones instead it searches which scheduler manages the element referred by the command (host/service) and sends the order to this scheduler. When the order is received by schedulers they just need to apply them.
Different types of Pollers: poller_tag
The current Shinken Enterprise architecture is useful for someone that uses the same type of poller for checks. But it can be useful to have different types of pollers. We already saw that all pollers talk to all schedulers. In fact, pollers can be "tagged" so that they will execute only some checks.
This is useful when the user needs to have hosts in the same scheduler (like with dependencies) but needs some hosts or services to be checked by specific pollers (see usage cases below).
These checks can in fact be tagged on 3 levels :
- Host
- Service
- Command
The parameter to tag a command, host or service, is "poller_tag". If a check uses a "tagged" or "untagged" command in a untagged host/service, it takes the poller_tag of this host/service. In a "untagged" host/service, it's the command tag that is taken into account.
The pollers can be tagged with multiple poller_tags. If they are tagged, they will only take checks that are tagged, not the untagged ones, unless they defined the tag "None".
It's mainly used when you have a DMZ network, you need to have a dedicated poller that is in the DMZ, and return results to a scheduler in LAN. With this, you can still have dependencies between DMZ hosts and LAN hosts, and still be sure that checks are done in a DMZ-only poller.