Hi
I’m trying to pull some metrics from a Prometheus data source using a query which requires nested variables.
I have defined three Custom Variables in my dashboard:
site = siteA,siteB
siteAhosts = server1,server2,server3
siteBhosts = server4,server5,server6
My panel query is simply calculating the cpu usage for the hosts selected:
(100 - cpu_usage_idle{host=~“$host”})
Note that this is just an indication of how I was using this query in the past when I had a single variable defined called “host”. Now I want to use nested variables in this query.
If siteA is selected as the “site”, then the query needs to be…
(100 - cpu_usage_idle{host=~“$siteAhosts”})
With the variable expanding to “server1,server2,server3”
If siteB is selected, then then the query needs to be…
(100 - cpu_usage_idle{host=~“$siteBhosts”})
With the variable expanding to “server4,server5,server6”
I’ve tried something like this…
(100 - cpu_usage_idel{host=~“${site}hosts”})
Which expands the site variable to siteA, but it fails to then expand the resulting siteAhosts variable and just treats it as a value.
Any ideas how I can achieve this? It’s driving me nuts 