Any way to provide default value when there's no data for table?

[ashiue01]

I’m a newbie with grafana so please be patient with me. I will try to fill out the template as much as I can.

• What Grafana version and what operating system are you using?
  Grafana v10.2.2

• What are you trying to achieve?
  I am using a table with the following query to get pod status and use it like an indicator:
  kube_pod_status_phase{namespace=“nuix-neo-tenant”, pod=~“investigate-deploy-.*”} == 1
  And depending on the value I set the cell colour. For example, Running is green, Failed is Red…etc.

The problem is before the pod exists, the table will show “No Data” and I want to see if there’s a way to have a default value so that I can actually colour it with some colour. Rather than just showing “No Data” with the default colour.

• How are you trying to achieve it?
  The problem is I don’t know how to achieve it. I know I can set the text with “No Value” field but that’s not really defaulting it to a value that can be used by value mapping.

I also read somewhere that some people uses “on() vector(0)” to set some default value but this didn’t work in my case.

• What happened?

• What did you expect to happen?

• Can you copy/paste the configuration(s) that you are having problems with?

• Did you receive any errors in the Grafana UI or in related logs? If so, please tell us exactly what they were.

• Did you follow any online instructions? If so, what is the URL?

[codi639]

Hello @ashiue01

I just tried using the doc and find a really easy way.
Go to value mapping, Add a mapping value then select special. From there you are able to pick up NULL value, which should work!

Regards

[ashiue01]

Hi @codi639 ,

Thanks a lot for the reply. I tried what you suggested that but it did not work for me. I even used both Null + NaN, then hit refresh button but still it shows no data and the colour is still the normal background.

[codi639]

Well, in PromQL (looks like that’s what you are using?), there’s no explicit value for an “empty value”… Can you try the last special option Empty string?

[ashiue01]

Thanks for the reply. I tried it as well, same result, nothing changed.

[codi639]

Okay, last guess I make: if it don’t work I’ll not be able to help you furthermore…

Try to put a value mapping using the string “Absent” or “absent” (something like this).
Hope it works!

[jangaraj]

[ashiue01]

Doesn’t work either, thanks a lot for your help. I will do a bit more research.

[ashiue01]

Thank you for your response but I also tried it and it’s still the same, the value mappings did not change the colour even if I set the “No value” field.

[jangaraj]

I gave you answer for your topic title “Any way to provide default value when there’s no data for table” - No value setting doesn’t change value actually (it just mask it visually), so you can’t use Value mapping setting to change color.

If you want: “Any way to provide default value AND COLOR when there’s no data for table”, then:
create promql query (*), which return some special value, which metric can’t have (e.g. -1) when metric doesn’t exist and use that value in Value mapping (-1 => text: text, color: red)

* How to write that promql is another topic - you need “if else” in promql: prometheus - PromQL if/else like expression - Stack Overflow - so develop that query for your case

[ashiue01]

Yep, sorry about my misleading title. It’s more like actually change the value rather than just showing something. I’m new to grafana so I don’t even know how to write the PromQL properly and have been just using the builder. Thanks for your response and I will check out how to write if-else expression with PromQL.

[ashiue01]

Thanks a lot for the link to the post for if-else express for PromQL. I was able to achieve what I wanted via the PromQL. I marked your answer as the solution. Thanks again.

For others who might want to do the same thing as what I’m doing. Here’s the sample PromQL that I used to set values based on the phase metric and also has a case in case there’s “no data”:

(vector(1) and on() (kube_pod_status_phase{namespace="tenant", pod=~"app-.*", phase="Running"}==1)) or
(vector(2) and on() (kube_pod_status_phase{namespace="tenant", pod=~"app-.*", phase="Pending"}==1)) or
(vector(3) and on() (kube_pod_status_phase{namespace="tenant", pod=~"app-.*", phase="Failed"}==1)) or
on() vector(0)

Then I use the value mapping to change the display text and set the background colour.

[jangaraj]

It will be nice if you post that developed PromQL query here.