custom loki logging alerts are not being routed by the default user workload alertmanager config - which by default uses group_by namespace 

customers would need to add to the default config in order to route custom loki logging alerts...but if the label for `namespace` is added then the alerts will be routed by the default config 

~~~
$ oc exec -n openshift-user-workload-monitoring alertmanager-user-workload-0 -- amtool config show --alertmanager.url http://localhost:9093 
global:
  resolve_timeout: 5m
  http_config:
    follow_redirects: true
    enable_http2: true
  smtp_hello: localhost
  smtp_require_tls: true
  pagerduty_url: https://events.pagerduty.com/v2/enqueue
  opsgenie_api_url: https://api.opsgenie.com/
  wechat_api_url: https://qyapi.weixin.qq.com/cgi-bin/
  victorops_api_url: https://alert.victorops.com/integrations/generic/20131114/alert/
  telegram_api_url: https://api.telegram.org
  webex_api_url: https://webexapis.com/v1/messages
route:
  receiver: Default
  group_by:
  - namespace
  continue: false
receivers:
- name: Default
templates: []

~~~

always   

enable a separate alertmanager instance for UWL alert routing

~~~
apiVersion: v1
kind: ConfigMap
metadata:
  name: user-workload-monitoring-config
  namespace: openshift-user-workload-monitoring
data:
  config.yaml: |
    alertmanager:
      enabled: true 
      enableAlertmanagerConfig: true
~~~

Deploy an always firing custom loki logging alert: 
https://access.redhat.com/articles/7073775 

set up an alert notification endpoint in UWL alertmanager: 
https://docs.openshift.com/container-platform/4.16/observability/monitoring/managing-alerts.html#configuring-notifications-for-user-defined-alerts_managing-alerts 

without the namespace label the notification will not be sent  

default config routes custom loki logging alerting notifications in the same way as metric alerts