Yes, but have you configured the prometheus (the one which has alerting
rules) to have all four alertmanagers as its destination?
On Friday, 13 January 2023 at 12:55:49 UTC LukaszSz wrote:
> Yes Brian. As I mentioned in my post the Alertmangers are in cluster and
> this event is visible on my 4 alertmanagers.
> Problem which I described is that an alerts are firing twice and it
> generates duplication.
>
> On Friday, January 13, 2023 at 1:34:52 PM UTC+1 Brian Candler wrote:
>
>> Are the alertmanagers clustered? Then you should configure prometheus to
>> deliver the alert to *all* alertmanagers.
>>
>> On Friday, 13 January 2023 at 11:08:37 UTC LukaszSz wrote:
>>
>>> Hi guys,
>>>
>>> I have Prometheus in HA mode - 4 nodes - Prometheus+Aletmanager on each.
>>> Everything works fine but very often I experience issue that an alert is
>>> firing again even the event is already resolved by alertmanager.
>>>
>>> Below logs from example event(Chrony_Service_Down) recorded by
>>> alertmanager:
>>>
>>>
>>> ############################################################################################################
>>> (1) Jan 10 10:48:48 prometheus-01 alertmanager[1213219]:
>>> ts=2023-01-10T10:48:48.746Z caller=dispatch.go:165 level=debug
>>> component=dispatcher msg="Received alert"
>>> alert=Chrony_Service_Down[d8c020a][active]
>>>
>>> (2) Jan 10 10:49:19 prometheus-01 alertmanager[1213219]:
>>> ts=2023-01-10T10:49:19.460Z caller=nflog.go:553 level=debug component=nflog
>>> msg="gossiping new entry"
>>> entry="entry:<group_key:\"{}/{severity=\\\"page\\\"}:{alertname=\\\"Chrony_Service_Down\\\",
>>>
>>> datacenter=\\\"dc01\\\", exporter=\\\"node\\\", fqdn=\\\"
>>> server.example.com\\\", instance=\\\"server.example.com\\\",
>>> job=\\\"node\\\", monitoring_infra=\\\"prometheus-mon\\\",
>>> puppet_certname=\\\"server.example.com\\\", service=\\\"chrony\\\",
>>> severity=\\\"page\\\"}\" receiver:<group_name:\"opsgenie\"
>>> integration:\"opsgenie\" > timestamp:<seconds:1673347759 nanos:262824014 >
>>> firing_alerts:10151928354614242630 > expires_at:<seconds:1673779759
>>> nanos:262824014 > "
>>>
>>> (3) Jan 10 10:50:48 prometheus-01 alertmanager[1213219]:
>>> ts=2023-01-10T10:50:48.745Z caller=dispatch.go:165 level=debug
>>> component=dispatcher msg="Received alert"
>>> alert=Chrony_Service_Down[d8c020a][resolved]
>>>
>>> (4) Jan 10 10:51:29 prometheus-01 alertmanager[1213219]:
>>> ts=2023-01-10T10:51:29.183Z caller=nflog.go:553 level=debug component=nflog
>>> msg="gossiping new entry"
>>> entry="entry:<group_key:\"{}/{severity=\\\"page\\\"}:{alertname=\\\"Chrony_Service_Down\\\",
>>>
>>> datacenter=\\\"dc01\\\", exporter=\\\"node\\\", fqdn=\\\"
>>> server.example.com\\\", instance=\\\"server.example.com\\\",
>>> job=\\\"node\\\", monitoring_infra=\\\"prometheus-mon\\\",
>>> puppet_certname=\\\"server.example.com\\\", service=\\\"chrony\\\",
>>> severity=\\\"page\\\"}\" receiver:<group_name:\"opsgenie\"
>>> integration:\"opsgenie\" > timestamp:<seconds:1673347888 nanos:897562679 >
>>> resolved_alerts:10151928354614242630 > expires_at:<seconds:1673779888
>>> nanos:897562679 > "
>>>
>>> (5) Jan 10 10:51:49 prometheus-01 alertmanager[1213219]:
>>> ts=2023-01-10T10:51:49.745Z caller=nflog.go:553 level=debug component=nflog
>>> msg="gossiping new entry"
>>> entry="entry:<group_key:\"{}/{severity=\\\"page\\\"}:{alertname=\\\"Chrony_Service_Down\\\",
>>>
>>> datacenter=\\\"dc01\\\", exporter=\\\"node\\\", fqdn=\\\"
>>> server.example.com\\\", instance=\\\"server.example.com\\\",
>>> job=\\\"node\\\", monitoring_infra=\\\"prometheus-mon\\\",
>>> puppet_certname=\\\"server.example.com\\\", service=\\\"chrony\\\",
>>> severity=\\\"page\\\"}\" receiver:<group_name:\"opsgenie\"
>>> integration:\"opsgenie\" > timestamp:<seconds:1673347909 nanos:649205670 >
>>> firing_alerts:10151928354614242630 > expires_at:<seconds:1673779909
>>> nanos:649205670 > "
>>>
>>> (6) Jan 10 10:51:59 prometheus-01 alertmanager[1213219]:
>>> ts=2023-01-10T10:51:59.312Z caller=nflog.go:553 level=debug component=nflog
>>> msg="gossiping new entry"
>>> entry="entry:<group_key:\"{}/{severity=\\\"page\\\"}:{alertname=\\\"Chrony_Service_Down\\\",
>>>
>>> datacenter=\\\"dc01\\\", exporter=\\\"node\\\", fqdn=\\\"
>>> server.example.com\\\", instance=\\\"server.example.com\\\",
>>> job=\\\"node\\\", monitoring_infra=\\\"prometheus-mon\\\",
>>> puppet_certname=\\\"server.example.com\\\", service=\\\"chrony\\\",
>>> severity=\\\"page\\\"}\" receiver:<group_name:\"opsgenie\"
>>> integration:\"opsgenie\" > timestamp:<seconds:1673347919 nanos:137020780 >
>>> resolved_alerts:10151928354614242630 > expires_at:<seconds:1673779919
>>> nanos:137020780 > "
>>>
>>> (7) Jan 10 10:54:58 prometheus-01 alertmanager[1213219]:
>>> ts=2023-01-10T10:54:58.744Z caller=dispatch.go:165 level=debug
>>> component=dispatcher msg="Received alert"
>>> alert=Chrony_Service_Down[d8c020a][resolved]
>>>
>>> #############################################################################################################
>>>
>>> Interesting is line number 5 (Jan 10 10:51:49) where alertmanager fired
>>> alert second time even minute ago (Jan 10 10:50:48) the alert was marked as
>>> resolved.
>>> Such behavior generates duplicate alert in our system which is quite
>>> annoying in our scale.
>>>
>>> What is worth to mention:
>>> - For test purpose the event is scrapped by 4 Promethues
>>> servers(default) but alert rule is evaluated by one Promethues.
>>> - The event occurres only once so there is no flapping which might cause
>>> another alert firing.
>>>
>>> Thanks
>>>
>>
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