BTW, there is an online PromQL pretty-printer
here: https://jiacai2050.github.io/promql-prettier/
This formats your expression as:
* ( ( kubelet_volume_stats_used_bytes * on
(namespace, persistentvolumeclaim) group_left (storageclass, provisioner)
( kube_persistentvolumeclaim_info * on
(storageclass) group_left (provisioner)
kube_storageclass_info{provisioner=~"(.*rbd.csi.ceph.com)|(.*cephfs.csi.ceph.com)"}
) ) / ( kubelet_volume_stats_capacity_bytes
* on (namespace, persistentvolumeclaim) group_left (storageclass,
provisioner) ( kube_persistentvolumeclaim_info
* on (storageclass) group_left (provisioner)
kube_storageclass_info{provisioner=~"(.*rbd.csi.ceph.com)|(.*cephfs.csi.ceph.com)"}
) ) )> 0.75*
I think this makes it much easier to understand and break down - for
example, you can remove the ( .. ) > 0.75 wrapper easily.
Aside: you can use this format inside your alerting rules, using the YAML
multi-line syntax (|): just make sure the whole expression is indented
below the starting line.
expr: |
(
(
kubelet_volume_stats_used_bytes
* on (namespace, persistentvolumeclaim) group_left (storageclass,
provisioner)
(
kube_persistentvolumeclaim_info
* on (storageclass) group_left (provisioner)
kube_storageclass_info{provisioner=~"(.*rbd.csi.ceph.com)|(.*cephfs.csi.ceph.com)"}
)
)
/
(
kubelet_volume_stats_capacity_bytes
* on (namespace, persistentvolumeclaim) group_left (storageclass,
provisioner)
(
kube_persistentvolumeclaim_info
* on (storageclass) group_left (provisioner)
kube_storageclass_info{provisioner=~"(.*rbd.csi.ceph.com)|(.*cephfs.csi.ceph.com)"}
)
)
)
>
0.75
Anyway, I would proceed by testing this expression:
* kube_persistentvolumeclaim_info * on
(storageclass) group_left (provisioner)
kube_storageclass_info{provisioner=~"(.*rbd.csi.ceph.com)|(.*cephfs.csi.ceph.com)"}*
Then this one:
* kubelet_volume_stats_used_bytes * on (namespace,
persistentvolumeclaim) group_left (storageclass, provisioner) (
kube_persistentvolumeclaim_info * on (storageclass)
group_left (provisioner)
kube_storageclass_info{provisioner=~"(.*rbd.csi.ceph.com)|(.*cephfs.csi.ceph.com)"}
)*
Then if those are OK then do the same for the lower half, and then finally
combine them.
On Tuesday, 25 July 2023 at 14:58:35 UTC+1 Brian Candler wrote:
> You have lots of sub-expressions there. Try breaking them down into parts
> until you find where the error is: you can enter them into the PromQL web
> interface.
>
> A * on (uuu) group_left(vvv) B
> A * on (uuu) group_left(vvv) B * on (www) group_left(xxx) C
> A * on (uuu) group_left(vvv) B * on (www) group_left(xxx) C * on (yyy)
> group_left(zzz) D
> ... etc
>
> Then when you find the error, perform the LHS and RHS queries separately,
> and inspect the labels.
>
> The error is telling you that you have multiple instances of the same
> combination of labels on both sides of one of those operators. With an
> expression like
>
> A * on (foo,bar) group_left(...) B
>
> then every value of B must have a distinct (unique) combination of labels
> foo and bar, if there is at least one match on the A side. That is, one or
> more "A" must match exactly one "B", and the matching involves the on(...)
> labels.
>
> The solution could involve adding extra labels to the on(...) clause, but
> it really depends on what metrics you have there.
>
> On Tuesday, 25 July 2023 at 13:57:09 UTC+1 Rakesh Kollakandi wrote:
>
>> Hi,
>>
>> I have a query like below:
>>
>> (kubelet_volume_stats_used_bytes * on (namespace,persistentvolumeclaim)
>> group_left(storageclass, provisioner) (kube_persistentvolumeclaim_info * on
>> (storageclass) group_left(provisioner) kube_storageclass_info
>> {provisioner=~"(.*rbd.csi.ceph.com)|(.*cephfs.csi.ceph.com)"})) /
>> (kubelet_volume_stats_capacity_bytes * on (namespace,persistentvolumeclaim)
>> group_left(storageclass, provisioner) (kube_persistentvolumeclaim_info * on
>> (storageclass) group_left(provisioner) kube_storageclass_info
>> {provisioner=~"(.*rbd.csi.ceph.com)|(.*cephfs.csi.ceph.com)"})) > 0.75
>>
>> this query failed and report an error like below,
>>
>> many-to-many matching not allowed: matching labels must be unique on one
>> side
>>
>> Has anyone dealt with this specific error and can you recommend something?
>>
>
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