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how to represent status of something not associated with a single host?

3 messages in this thread

list Richard L. Hamilton · Fri, 21 Aug 2020 13:17:09 -0400 · 
Let's say I have something, in this case DHCP server failover status, that although the parts of it run on two or more hosts, isn't strictly associated with either one (ideally if both DHCP servers are up, they'd both show the same failover status for each other). It could be some other distributed processing state that doesn't depend on any single system to still be available.

Let's say even that I can write a server-side script for it.  Where the heck should I show the information? Maybe make up a fake host for global state like that, suppress display of all the usual probes for it, and only show the ones I want?
list Damien Martins · Fri, 21 Aug 2020 19:24:31 +0200 · 
Hi Richard,

I use to think that when several hosts are bond together for providing a specific service, I would consider this is a cluster. Hence, I invite you to create a fake host that could embed all of your clustered services, and design some tests.

Le 21/08/2020 ? 19:17, Richard L. Hamilton a ?crit?:
▸ quoted from Richard L. Hamilton
Let's say I have something, in this case DHCP server failover status, that although the parts of it run on two or more hosts, isn't strictly associated with either one (ideally if both DHCP servers are up, they'd both show the same failover status for each other). It could be some other distributed processing state that doesn't depend on any single system to still be available.

Let's say even that I can write a server-side script for it.  Where the heck should I show the information? Maybe make up a fake host for global state like that, suppress display of all the usual probes for it, and only show the ones I want?
list Andy Smith · Fri, 21 Aug 2020 18:48:51 +0100 · 
Hi,

I have used the combo test to great effect in these circumstances.? Configure a standard network test (eg smtp) on each server, but exclude the smtp column from the row for that server.? Then configure a combo test for some made-up server name on separate row, you can play with NAME in hosts.cfg to display something useful on the page instead of your made-up name. ? My combo.cfg may contain something like this:

MyImportantService.SMTP_PRD.smtp = ( \
server1.smtp && \
server2.smtp \
)

Just a couple of things that caught me out that you may want to beware of ...

1) Test names are stored internally by first usage and subsequent matches are done ignoring case, so if for example, dbcheck.pl has defined a test called "Cluster" then all the following will match :-
 ???? cluster -> Cluster
 ???? CLUSTER -> Cluster
 ???? CluSter -> Cluster
so even if you define your column names in lower case, they will appear on the display in original case.
2) host names with dashes must be escaped because My-Important-Service will be interpreted as algebra if it appears on the RHS of any rule.

-- 
Andy
▸ quoted from Richard L. Hamilton

On 21/08/2020 18:17, Richard L. Hamilton wrote:

Let's say I have something, in this case DHCP server failover status, that although the parts of it run on two or more hosts, isn't strictly associated with either one (ideally if both DHCP servers are up, they'd both show the same failover status for each other). It could be some other distributed processing state that doesn't depend on any single system to still be available.

Let's say even that I can write a server-side script for it.  Where the heck should I show the information? Maybe make up a fake host for global state like that, suppress display of all the usual probes for it, and only show the ones I want?