Configure Prometheus Email Alert Notifications

Configure an email alert notification for all Prometheus Postgres replication alerts: PostgresReplicationLagSMA, PostgresReplicationServices, PostgresqlFollowerReplicationLagSMA, and PostgresqlFollowerReplicationLagServices.

System domain name

The SYSTEM_DOMAIN_NAME value found in some of the URLs on this page is expected to be the system’s fully qualified domain name (FQDN).

(ncn-mw#) The FQDN can be found by running the following command on any Kubernetes NCN.

kubectl get secret site-init -n loftsman -o jsonpath='{.data.customizations\.yaml}' | base64 -d | yq r - spec.network.dns.external

Example output:

system.hpc.amslabs.hpecorp.net

Be sure to modify the example URLs on this page by replacing SYSTEM_DOMAIN_NAME with the actual value found using the above command.

Procedure

This procedure can be performed on any master or worker NCN.

  1. (ncn-mw#) Save the current alert notification configuration, in case a rollback is needed.

    kubectl get secret -n sysmgmt-health alertmanager-config \
        -ojsonpath='{.data.alertmanager\.yaml}' | base64 --decode > /tmp/alertmanager-default.yaml

  2. (ncn-mw#) Create a secret and an alert configuration that will be used to add email notifications for the alerts.

    1. Create the secret file.

      Create a file named /tmp/alertmanager-secret.yaml with the following contents:

      apiVersion: v1
data:
  alertmanager.yaml: ALERTMANAGER_CONFIG
kind: Secret
metadata:
  labels:
    app.kubernetes.io/component: monitoring
    app.kubernetes.io/instance: vms
    app.kubernetes.io/name: vmalertmanager
  name: alertmanager-config
  namespace: sysmgmt-health
type: Opaque

    2. Create the alert configuration file.

      In the following example file, the Gmail SMTP server is used in this example to relay the notification to receiver-email@yourcompany.com. Update the fields under email_configs: to reflect the desired configuration.

      Create a file named /tmp/alertmanager-new.yaml with the following contents:

      global:
  resolve_timeout: 5h
route:
  group_by:
  - group
  group_interval: 5m
  group_wait: 30s
  receiver: "null"
  repeat_interval: 12h
  routes:
  - match:
      alertname: Watchdog
    receiver: "null"
  - match:
      alertname: PostgresqlReplicationLagSMA
    receiver:  email-alert
  - match:
      alertname: PostgresqlReplicationLagServices
    receiver:  email-alert
  - match:
      alertname: PostgresqlFollowerReplicationLagSMA
    receiver:  email-alert
  - match:
      alertname: PostgresqlFollowerReplicationLagServices
    receiver:  email-alert
receivers:
- name: "null"
- name: email-alert
  email_configs:
  - to: receiver-email@yourcompany.com
    from: sender-email@gmail.com
    # Your smtp server address
    require_tls: false
    smarthost: smtp.gmail.com:587
    auth_username: sender-email@gmail.com
    auth_identity: sender-email@gmail.com
    auth_password: xxxxxxxxxxxxxxxx

NOTE: set require_tls: false per receiver, if tls needs to be disabled.

  1. (ncn-mw#) Replace the alert notification configuration based on the files created in the previous steps.

    sed "s/ALERTMANAGER_CONFIG/$(cat /tmp/alertmanager-new.yaml \
            | base64 -w0)/g" /tmp/alertmanager-secret.yaml \
            | kubectl replace --force -f -

  2. (ncn-mw#) Validate the configuration changes.

    1. View the current configuration.

      kubectl exec vmalertmanager-vms-0 \
        -n sysmgmt-health -c alertmanager -- cat /etc/alertmanager/config/alertmanager.yaml

    2. If the configuration does not look accurate, check the logs for errors.

      kubectl logs -f -n sysmgmt-health pod/vmalertmanager-vms-0 alertmanager

An email notification will be sent once either of the alerts set in this procedure is FIRING in Prometheus. See https://vmselect.cmn.SYSTEM_DOMAIN_NAME/select/0/prometheus/vmalert/api/v1/alerts for more information.

If an alert is received, then refer to Troubleshoot Postgres Database for more information about recovering replication.