That looks correct to me. What were you expecting to see instead?
Alerts trigger when the expression returns one or more timeseries, with
*any* value. Even an expression with value 0 will trigger an alert. So to
prevent triggering the alert, the expression has to return an empty set of
timeseries (i.e. no result).
You should find that
foo and on () (day_of_week() == 0 or day_of_week() == 6)
masks the expression foo so that the result is empty except for those two
days of the week.
Try comparing the graphs of:
datapipeline_coordinator_status{...blah...} == 1
datapipeline_coordinator_status{...blah...} == 1 and on () (day_of_week()
== 0 or day_of_week() == 6)
Does it make sense now?
(You didn't describe the meaning of the datapipeline_coordinator_status
metric, but I'm presuming from that expression that you want it to alert
when the value is 1)
On Friday, 6 August 2021 at 12:58:54 UTC+1 [email protected] wrote:
> Hello Brian,
>
> Thank you so much for your input. I have already tried with that option
> below, but not sure if the output is expected.
> > up == 1 and on () (day_of_week() == 4 or day_of_week() == 5) # correct.
>
> Please find the attachment.
>
> Thanks,
> Kishore
>
> On Thu, Aug 5, 2021 at 2:05 PM Brian Candler <[email protected]> wrote:
>
>> Correction:
>>
>> *I suspect that*
>> *foo and on() bar or baz*
>> *will be parsed as*
>> *(foo and on() bar) or baz*
>> *which is not what you require.*
>>
>> On Thursday, 5 August 2021 at 09:34:22 UTC+1 Brian Candler wrote:
>>
>>> Please don't just say "it doesn't work". Say what happened. Did you
>>> see an error message? Did the alert fire when you were not expecting it,
>>> or not fire when you were expecting it?
>>>
>>> Adding "if: ..." to an alerting rule shouldn't work - I cannot see that
>>> syntax anywhere in the documentation
>>> <https://prometheus.io/docs/prometheus/latest/configuration/recording_rules/>.
>>>
>>> You need to put the logic into the expr: and you can debug your expr using
>>> the prometheus query GUI (*).
>>>
>>> Adding parentheses might help. I suspect that
>>> foo and on() bar or baz
>>> will be parsed as
>>> (foo and (on() bar)) or baz
>>> which is not what you require.
>>>
>>> Because you're using on() I think you're already aware that "and", "or"
>>> and "==" don't work the way that newcomers expect. To summarize:
>>>
>>> Comparison operators
>>> <https://prometheus.io/docs/prometheus/latest/querying/operators/#comparison-binary-operators>
>>> foo : is a set of timeseries.
>>> foo{bar="baz"} : is the same set of timeseries, filtered down to only
>>> those with label bar="baz".
>>> foo{bar="baz"} == 1 : is the same set of timeseries, filtered down to
>>> only those with label bar="baz" and whose value is 1.
>>>
>>> Logical operators
>>> <https://prometheus.io/docs/prometheus/latest/querying/operators/#logical-set-binary-operators>
>>> foo and bar : is the set of timeseries from foo, filtered to only those
>>> where bar exists with the exact same set of labels (but any value). Given
>>> that *day_of_week() == 6* is a scalar value (6) it has no labels.
>>>
>>> (*) You can test your expression in the PromQL browser like this: try
>>> selecting the graph view and scrolling out so you display 2 weeks.
>>>
>>> up == 1 # ok
>>> up == 1 and day_of_week() == 4 # no results
>>> up == 1 and on() day_of_week() == 4 # works
>>> up == 1 and on () day_of_week() == 4 or day_of_week() == 5 #
>>> unexpected: gives value 1 or value 5
>>> up == 1 and on () (day_of_week() == 4 or day_of_week() == 5) # correct
>>>
>>> I think this confirms that your problem is lack of parentheses.
>>>
>>> On Thursday, 5 August 2021 at 05:22:47 UTC+1 [email protected] wrote:
>>>
>>>> Hello All,
>>>>
>>>> I want to set up an alert monitoring for a job/service which is running
>>>> only on weekends.
>>>> Alerts should trigger during weekend if the service is not running or
>>>> goes down.
>>>>
>>>> Tried with below query (just for testing, in actual query value would
>>>> be 0). PFA
>>>>
>>>> *d********_status{job="targets",name="d*-*******ise-*****re-coord"} ==
>>>> 1 and on() day_of_week() == 6 or day_of_week() == 0*
>>>>
>>>> Also in alert rules applied if condition
>>>> - alert: "[EMR]: Java coordinator is down"
>>>> *if: day_of_week() == 0 OR day_of_week() == 6*
>>>>
>>>> But neither of them working*.*
>>>>
>>>> Thanks,
>>>> Kishore
>>>>
>>> --
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>>
>
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