Chapter 6. Configuring secrets for Alertmanager

Procedure

1. Open the Alertmanager YAML configuration file:

   • To open the Alertmanager configuration from the CLI:

     1. Print the currently active Alertmanager configuration from the alertmanager-main secret into alertmanager.yaml file:

        $ oc -n openshift-monitoring get secret alertmanager-main --template='{{ index .data "alertmanager.yaml" }}' | base64 --decode > alertmanager.yaml

     2. Open the alertmanager.yaml file.

   • To open the Alertmanager configuration from the OpenShift Container Platform web console:

     1. Go to the Administration Cluster Settings Configuration Alertmanager YAML page of the web console.

2. Edit the Alertmanager configuration by updating parameters in the YAML:

   global:
     resolve_timeout: 5m
   route:
     group_wait: 30s 1
     group_interval: 5m 2
     repeat_interval: 12h 3
     receiver: default
     routes:
     - matchers:
       - "alertname=Watchdog"
       repeat_interval: 2m
       receiver: watchdog
     - matchers:
       - "service=<your_service>" 4
       routes:
       - matchers:
         - <your_matching_rules> 5
         receiver: <receiver> 6
   receivers:
   - name: default
   - name: watchdog
   - name: <receiver>
     <receiver_configuration> 7

   1

   Specify how long Alertmanager waits while collecting initial alerts for a group of alerts before sending a notification.

   2

   Specify how much time must elapse before Alertmanager sends a notification about new alerts added to a group of alerts for which an initial notification was already sent.

   3

   Specify the minimum amount of time that must pass before an alert notification is repeated. If you want a notification to repeat at each group interval, set the repeat_interval value to less than the group_interval value. The repeated notification can still be delayed, for example, when certain Alertmanager pods are restarted or rescheduled.

   4

   Specify the name of the service that fires the alerts.

   5

   Specify labels to match your alerts.

   6

   Specify the name of the receiver to use for the alerts.

   7

   Specify the receiver configuration.

   Important
   • Use the matchers key name to indicate the matchers that an alert has to fulfill to match the node. Do not use the match or match_re key names, which are both deprecated and planned for removal in a future release.

   • If you define inhibition rules, use the following key names:

     • target_matchers: to indicate the target matchers
     • source_matchers: to indicate the source matchers

     Do not use the target_match, target_match_re, source_match, or source_match_re key names, which are deprecated and planned for removal in a future release.

   The following Alertmanager configuration example configures PagerDuty as an alert receiver:

   global:
     resolve_timeout: 5m
   route:
     group_wait: 30s
     group_interval: 5m
     repeat_interval: 12h
     receiver: default
     routes:
     - matchers:
       - "alertname=Watchdog"
       repeat_interval: 2m
       receiver: watchdog
     - matchers:
       - "service=example-app"
       routes:
       - matchers:
         - "severity=critical"
         receiver: team-frontend-page
   receivers:
   - name: default
   - name: watchdog
   - name: team-frontend-page
     pagerduty_configs:
     - service_key: "<your_key>"

   With this configuration, alerts of critical severity that are fired by the example-app service are sent through the team-frontend-page receiver. Typically, these types of alerts would be paged to an individual or a critical response team.

3. Apply the new configuration in the file:

   • To apply the changes from the CLI, run the following command:

     $ oc -n openshift-monitoring create secret generic alertmanager-main --from-file=alertmanager.yaml --dry-run=client -o=yaml |  oc -n openshift-monitoring replace secret --filename=-

   • To apply the changes from the OpenShift Container Platform web console, click Save.

Procedure

1. In the Administrator perspective, go to Administration Cluster Settings Configuration Alertmanager.

   Note

   Alternatively, you can go to the same page through the notification drawer. Select the bell icon at the top right of the OpenShift Container Platform web console and choose Configure in the AlertmanagerReceiverNotConfigured alert.

2. Click Create Receiver in the Receivers section of the page.
3. In the Create Receiver form, add a Receiver name and choose a Receiver type from the list.

4. Edit the receiver configuration:

   • For PagerDuty receivers:

     1. Choose an integration type and add a PagerDuty integration key.
     2. Add the URL of your PagerDuty installation.
     3. Click Show advanced configuration if you want to edit the client and incident details or the severity specification.

   • For webhook receivers:

     1. Add the endpoint to send HTTP POST requests to.
     2. Click Show advanced configuration if you want to edit the default option to send resolved alerts to the receiver.

   • For email receivers:

     1. Add the email address to send notifications to.
     2. Add SMTP configuration details, including the address to send notifications from, the smarthost and port number used for sending emails, the hostname of the SMTP server, and authentication details.
     3. Select whether TLS is required.
     4. Click Show advanced configuration if you want to edit the default option not to send resolved alerts to the receiver or edit the body of email notifications configuration.

   • For Slack receivers:

     1. Add the URL of the Slack webhook.
     2. Add the Slack channel or user name to send notifications to.
     3. Select Show advanced configuration if you want to edit the default option not to send resolved alerts to the receiver or edit the icon and username configuration. You can also choose whether to find and link channel names and usernames.

5. By default, firing alerts with labels that match all of the selectors are sent to the receiver. If you want label values for firing alerts to be matched exactly before they are sent to the receiver, perform the following steps:

   1. Add routing label names and values in the Routing labels section of the form.
   2. Click Add label to add further routing labels.
6. Click Create to create the receiver.