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Chapter 10. Managing alerts
In OpenShift Dedicated 4, the Alerting UI enables you to manage alerts, silences, and alerting rules.
- Alerting rules. Alerting rules contain a set of conditions that outline a particular state within a cluster. Alerts are triggered when those conditions are true. An alerting rule can be assigned a severity that defines how the alerts are routed.
- Alerts. An alert is fired when the conditions defined in an alerting rule are true. Alerts provide a notification that a set of circumstances are apparent within an OpenShift Dedicated cluster.
- Silences. A silence can be applied to an alert to prevent notifications from being sent when the conditions for an alert are true. You can mute an alert after the initial notification, while you work on resolving the issue.
The alerts, silences, and alerting rules that are available in the Alerting UI relate to the projects that you have access to. For example, if you are logged in as a user with the cluster-admin
role, you can access all alerts, silences, and alerting rules.
10.1. Accessing the Alerting UI in the Administrator and Developer perspectives
The Alerting UI is accessible through the Administrator perspective and the Developer perspective of the OpenShift Dedicated web console.
-
In the Administrator perspective, go to Observe
Alerting. The three main pages in the Alerting UI in this perspective are the Alerts, Silences, and Alerting rules pages.
-
In the Developer perspective, go to Observe
<project_name> Alerts. In this perspective, alerts, silences, and alerting rules are all managed from the Alerts page. The results shown in the Alerts page are specific to the selected project.
In the Developer perspective, you can select from core OpenShift Dedicated and user-defined projects that you have access to in the Project: <project_name> list. However, alerts, silences, and alerting rules relating to core OpenShift Dedicated projects are not displayed if you are not logged in as a cluster administrator.
10.2. Searching and filtering alerts, silences, and alerting rules
You can filter the alerts, silences, and alerting rules that are displayed in the Alerting UI. This section provides a description of each of the available filtering options.
Understanding alert filters
In the Administrator perspective, the Alerts page in the Alerting UI provides details about alerts relating to default OpenShift Dedicated and user-defined projects. The page includes a summary of severity, state, and source for each alert. The time at which an alert went into its current state is also shown.
You can filter by alert state, severity, and source. By default, only Platform alerts that are Firing are displayed. The following describes each alert filtering option:
State filters:
-
Firing. The alert is firing because the alert condition is true and the optional
for
duration has passed. The alert continues to fire while the condition remains true. - Pending. The alert is active but is waiting for the duration that is specified in the alerting rule before it fires.
- Silenced. The alert is now silenced for a defined time period. Silences temporarily mute alerts based on a set of label selectors that you define. Notifications are not sent for alerts that match all the listed values or regular expressions.
-
Firing. The alert is firing because the alert condition is true and the optional
Severity filters:
- Critical. The condition that triggered the alert could have a critical impact. The alert requires immediate attention when fired and is typically paged to an individual or to a critical response team.
- Warning. The alert provides a warning notification about something that might require attention to prevent a problem from occurring. Warnings are typically routed to a ticketing system for non-immediate review.
- Info. The alert is provided for informational purposes only.
- None. The alert has no defined severity.
- You can also create custom severity definitions for alerts relating to user-defined projects.
Source filters:
- Platform. Platform-level alerts relate only to default OpenShift Dedicated projects. These projects provide core OpenShift Dedicated functionality.
- User. User alerts relate to user-defined projects. These alerts are user-created and are customizable. User-defined workload monitoring can be enabled postinstallation to provide observability into your own workloads.
Understanding silence filters
In the Administrator perspective, the Silences page in the Alerting UI provides details about silences applied to alerts in default OpenShift Dedicated and user-defined projects. The page includes a summary of the state of each silence and the time at which a silence ends.
You can filter by silence state. By default, only Active and Pending silences are displayed. The following describes each silence state filter option:
State filters:
- Active. The silence is active and the alert will be muted until the silence is expired.
- Pending. The silence has been scheduled and it is not yet active.
- Expired. The silence has expired and notifications will be sent if the conditions for an alert are true.
Understanding alerting rule filters
In the Administrator perspective, the Alerting rules page in the Alerting UI provides details about alerting rules relating to default OpenShift Dedicated and user-defined projects. The page includes a summary of the state, severity, and source for each alerting rule.
You can filter alerting rules by alert state, severity, and source. By default, only Platform alerting rules are displayed. The following describes each alerting rule filtering option:
Alert state filters:
-
Firing. The alert is firing because the alert condition is true and the optional
for
duration has passed. The alert continues to fire while the condition remains true. - Pending. The alert is active but is waiting for the duration that is specified in the alerting rule before it fires.
- Silenced. The alert is now silenced for a defined time period. Silences temporarily mute alerts based on a set of label selectors that you define. Notifications are not sent for alerts that match all the listed values or regular expressions.
- Not Firing. The alert is not firing.
-
Firing. The alert is firing because the alert condition is true and the optional
Severity filters:
- Critical. The conditions defined in the alerting rule could have a critical impact. When true, these conditions require immediate attention. Alerts relating to the rule are typically paged to an individual or to a critical response team.
- Warning. The conditions defined in the alerting rule might require attention to prevent a problem from occurring. Alerts relating to the rule are typically routed to a ticketing system for non-immediate review.
- Info. The alerting rule provides informational alerts only.
- None. The alerting rule has no defined severity.
- You can also create custom severity definitions for alerting rules relating to user-defined projects.
Source filters:
- Platform. Platform-level alerting rules relate only to default OpenShift Dedicated projects. These projects provide core OpenShift Dedicated functionality.
- User. User-defined workload alerting rules relate to user-defined projects. These alerting rules are user-created and are customizable. User-defined workload monitoring can be enabled postinstallation to provide observability into your own workloads.
Searching and filtering alerts, silences, and alerting rules in the Developer perspective
In the Developer perspective, the Alerts page in the Alerting UI provides a combined view of alerts and silences relating to the selected project. A link to the governing alerting rule is provided for each displayed alert.
In this view, you can filter by alert state and severity. By default, all alerts in the selected project are displayed if you have permission to access the project. These filters are the same as those described for the Administrator perspective.
10.3. Getting information about alerts, silences, and alerting rules
The Alerting UI provides detailed information about alerts and their governing alerting rules and silences.
Prerequisites
- You have access to the cluster as a developer or as a user with view permissions for the project that you are viewing alerts for.
Procedure
To obtain information about alerts in the Administrator perspective:
-
Open the OpenShift Dedicated web console and go to the Observe
Alerting Alerts page. - Optional: Search for alerts by name by using the Name field in the search list.
- Optional: Filter alerts by state, severity, and source by selecting filters in the Filter list.
- Optional: Sort the alerts by clicking one or more of the Name, Severity, State, and Source column headers.
Click the name of an alert to view its Alert details page. The page includes a graph that illustrates alert time series data. It also provides the following information about the alert:
- A description of the alert
- Messages associated with the alert
- Labels attached to the alert
- A link to its governing alerting rule
- Silences for the alert, if any exist
To obtain information about silences in the Administrator perspective:
-
Go to the Observe
Alerting Silences page. - Optional: Filter the silences by name using the Search by name field.
- Optional: Filter silences by state by selecting filters in the Filter list. By default, Active and Pending filters are applied.
- Optional: Sort the silences by clicking one or more of the Name, Firing alerts, State, and Creator column headers.
Select the name of a silence to view its Silence details page. The page includes the following details:
- Alert specification
- Start time
- End time
- Silence state
- Number and list of firing alerts
To obtain information about alerting rules in the Administrator perspective:
-
Go to the Observe
Alerting Alerting rules page. - Optional: Filter alerting rules by state, severity, and source by selecting filters in the Filter list.
- Optional: Sort the alerting rules by clicking one or more of the Name, Severity, Alert state, and Source column headers.
Select the name of an alerting rule to view its Alerting rule details page. The page provides the following details about the alerting rule:
- Alerting rule name, severity, and description.
- The expression that defines the condition for firing the alert.
- The time for which the condition should be true for an alert to fire.
- A graph for each alert governed by the alerting rule, showing the value with which the alert is firing.
- A table of all alerts governed by the alerting rule.
To obtain information about alerts, silences, and alerting rules in the Developer perspective:
-
Go to the Observe
<project_name> Alerts page. View details for an alert, silence, or an alerting rule:
- Alert details can be viewed by clicking a greater than symbol (>) next to an alert name and then selecting the alert from the list.
Silence details can be viewed by clicking a silence in the Silenced by section of the Alert details page. The Silence details page includes the following information:
- Alert specification
- Start time
- End time
- Silence state
- Number and list of firing alerts
- Alerting rule details can be viewed by clicking the menu next to an alert in the Alerts page and then clicking View Alerting Rule.
Only alerts, silences, and alerting rules relating to the selected project are displayed in the Developer perspective.
Additional resources
- See the Cluster Monitoring Operator runbooks to help diagnose and resolve issues that trigger specific OpenShift Dedicated monitoring alerts.
10.4. Managing silences
You can create a silence for an alert in the OpenShift Dedicated web console in both the Administrator and Developer perspectives. After you create a silence, you will not receive notifications about an alert when the alert fires.
Creating silences is useful in scenarios where you have received an initial alert notification, and you do not want to receive further notifications during the time in which you resolve the underlying issue causing the alert to fire.
When creating a silence, you must specify whether it becomes active immediately or at a later time. You must also set a duration period after which the silence expires.
After you create silences, you can view, edit, and expire them.
When you create silences, they are replicated across Alertmanager pods. However, if you do not configure persistent storage for Alertmanager, silences might be lost. This can happen, for example, if all Alertmanager pods restart at the same time.
Additional resources
10.4.1. Silencing alerts
You can silence a specific alert or silence alerts that match a specification that you define.
Prerequisites
-
If you are a cluster administrator, you have access to the cluster as a user with the
dedicated-admin
role. If you are a non-administrator user, you have access to the cluster as a user with the following user roles:
-
The
cluster-monitoring-view
cluster role, which allows you to access Alertmanager. -
The
monitoring-alertmanager-edit
role, which permits you to create and silence alerts in the Administrator perspective in the web console. -
The
monitoring-rules-edit
cluster role, which permits you to create and silence alerts in the Developer perspective in the web console.
-
The
Procedure
To silence a specific alert in the Administrator perspective:
-
Go to Observe
Alerting Alerts in the OpenShift Dedicated web console. - For the alert that you want to silence, click and select Silence alert to open the Silence alert page with a default configuration for the chosen alert.
Optional: Change the default configuration details for the silence.
NoteYou must add a comment before saving a silence.
- To save the silence, click Silence.
To silence a specific alert in the Developer perspective:
-
Go to Observe
<project_name> Alerts in the OpenShift Dedicated web console. - If necessary, expand the details for the alert by selecting a greater than symbol (>) next to the alert name.
- Click the alert message in the expanded view to open the Alert details page for the alert.
- Click Silence alert to open the Silence alert page with a default configuration for the alert.
Optional: Change the default configuration details for the silence.
NoteYou must add a comment before saving a silence.
- To save the silence, click Silence.
To silence a set of alerts by creating a silence configuration in the Administrator perspective:
-
Go to Observe
Alerting Silences in the OpenShift Dedicated web console. - Click Create silence.
On the Create silence page, set the schedule, duration, and label details for an alert.
NoteYou must add a comment before saving a silence.
- To create silences for alerts that match the labels that you entered, click Silence.
To silence a set of alerts by creating a silence configuration in the Developer perspective:
-
Go to Observe
<project_name> Silences in the OpenShift Dedicated web console. - Click Create silence.
On the Create silence page, set the duration and label details for an alert.
NoteYou must add a comment before saving a silence.
- To create silences for alerts that match the labels that you entered, click Silence.
10.4.2. Editing silences
You can edit a silence, which expires the existing silence and creates a new one with the changed configuration.
Prerequisites
-
If you are a cluster administrator, you have access to the cluster as a user with the
dedicated-admin
role. If you are a non-administrator user, you have access to the cluster as a user with the following user roles:
-
The
cluster-monitoring-view
cluster role, which allows you to access Alertmanager. -
The
monitoring-alertmanager-edit
role, which permits you to create and silence alerts in the Administrator perspective in the web console. -
The
monitoring-rules-edit
cluster role, which permits you to create and silence alerts in the Developer perspective in the web console.
-
The
Procedure
To edit a silence in the Administrator perspective:
-
Go to Observe
Alerting Silences. For the silence you want to modify, click and select Edit silence.
Alternatively, you can click Actions and select Edit silence on the Silence details page for a silence.
- On the Edit silence page, make changes and click Silence. Doing so expires the existing silence and creates one with the updated configuration.
To edit a silence in the Developer perspective:
-
Go to Observe
<project_name> Silences. For the silence you want to modify, click and select Edit silence.
Alternatively, you can click Actions and select Edit silence on the Silence details page for a silence.
- On the Edit silence page, make changes and click Silence. Doing so expires the existing silence and creates one with the updated configuration.
10.4.3. Expiring silences
You can expire a single silence or multiple silences. Expiring a silence deactivates it permanently.
You cannot delete expired, silenced alerts. Expired silences older than 120 hours are garbage collected.
Prerequisites
-
If you are a cluster administrator, you have access to the cluster as a user with the
dedicated-admin
role. If you are a non-administrator user, you have access to the cluster as a user with the following user roles:
-
The
cluster-monitoring-view
cluster role, which allows you to access Alertmanager. -
The
monitoring-alertmanager-edit
role, which permits you to create and silence alerts in the Administrator perspective in the web console. -
The
monitoring-rules-edit
cluster role, which permits you to create and silence alerts in the Developer perspective in the web console.
-
The
Procedure
To expire a silence or silences in the Administrator perspective:
-
Go to Observe
Alerting Silences. - For the silence or silences you want to expire, select the checkbox in the corresponding row.
Click Expire 1 silence to expire a single selected silence or Expire <n> silences to expire multiple selected silences, where <n> is the number of silences you selected.
Alternatively, to expire a single silence you can click Actions and select Expire silence on the Silence details page for a silence.
To expire a silence in the Developer perspective:
-
Go to Observe
<project_name> Silences. - For the silence or silences you want to expire, select the checkbox in the corresponding row.
Click Expire 1 silence to expire a single selected silence or Expire <n> silences to expire multiple selected silences, where <n> is the number of silences you selected.
Alternatively, to expire a single silence you can click Actions and select Expire silence on the Silence details page for a silence.
10.5. Managing alerting rules for user-defined projects
OpenShift Dedicated monitoring ships with a set of default alerting rules. As a cluster administrator, you can view the default alerting rules.
In OpenShift Dedicated 4, you can create, view, edit, and remove alerting rules in user-defined projects.
Managing alerting rules for user-defined projects is only available in OpenShift Dedicated version 4.11 and later.
Alerting rule considerations
- The default alerting rules are used specifically for the OpenShift Dedicated cluster.
- Some alerting rules intentionally have identical names. They send alerts about the same event with different thresholds, different severity, or both.
- Inhibition rules prevent notifications for lower severity alerts that are firing when a higher severity alert is also firing.
10.5.1. Optimizing alerting for user-defined projects
You can optimize alerting for your own projects by considering the following recommendations when creating alerting rules:
- Minimize the number of alerting rules that you create for your project. Create alerting rules that notify you of conditions that impact you. It is more difficult to notice relevant alerts if you generate many alerts for conditions that do not impact you.
- Create alerting rules for symptoms instead of causes. Create alerting rules that notify you of conditions regardless of the underlying cause. The cause can then be investigated. You will need many more alerting rules if each relates only to a specific cause. Some causes are then likely to be missed.
- Plan before you write your alerting rules. Determine what symptoms are important to you and what actions you want to take if they occur. Then build an alerting rule for each symptom.
- Provide clear alert messaging. State the symptom and recommended actions in the alert message.
- Include severity levels in your alerting rules. The severity of an alert depends on how you need to react if the reported symptom occurs. For example, a critical alert should be triggered if a symptom requires immediate attention by an individual or a critical response team.
Additional resources
- See the Prometheus alerting documentation for further guidelines on optimizing alerts
10.5.2. About creating alerting rules for user-defined projects
If you create alerting rules for a user-defined project, consider the following key behaviors and important limitations when you define the new rules:
A user-defined alerting rule can include metrics exposed by its own project in addition to the default metrics from core platform monitoring. You cannot include metrics from another user-defined project.
For example, an alerting rule for the
ns1
user-defined project can use metrics exposed by thens1
project in addition to core platform metrics, such as CPU and memory metrics. However, the rule cannot include metrics from a differentns2
user-defined project.To reduce latency and to minimize the load on core platform monitoring components, you can add the
openshift.io/prometheus-rule-evaluation-scope: leaf-prometheus
label to a rule. This label forces only the Prometheus instance deployed in theopenshift-user-workload-monitoring
project to evaluate the alerting rule and prevents the Thanos Ruler instance from doing so.ImportantIf an alerting rule has this label, your alerting rule can use only those metrics exposed by your user-defined project. Alerting rules you create based on default platform metrics might not trigger alerts.
10.5.3. Creating alerting rules for user-defined projects
You can create alerting rules for user-defined projects. Those alerting rules will trigger alerts based on the values of the chosen metrics.
- When you create an alerting rule, a project label is enforced on it even if a rule with the same name exists in another project.
- To help users understand the impact and cause of the alert, ensure that your alerting rule contains an alert message and severity value.
Prerequisites
- You have enabled monitoring for user-defined projects.
-
You are logged in as a user that has the
monitoring-rules-edit
cluster role for the project where you want to create an alerting rule. -
You have installed the OpenShift CLI (
oc
).
Procedure
-
Create a YAML file for alerting rules. In this example, it is called
example-app-alerting-rule.yaml
. Add an alerting rule configuration to the YAML file. The following example creates a new alerting rule named
example-alert
. The alerting rule fires an alert when theversion
metric exposed by the sample service becomes0
:apiVersion: monitoring.coreos.com/v1 kind: PrometheusRule metadata: name: example-alert namespace: ns1 spec: groups: - name: example rules: - alert: VersionAlert 1 for: 1m 2 expr: version{job="prometheus-example-app"} == 0 3 labels: severity: warning 4 annotations: message: This is an example alert. 5
Apply the configuration file to the cluster:
$ oc apply -f example-app-alerting-rule.yaml
Additional resources
- See Monitoring overview for details about OpenShift Dedicated 4 monitoring architecture.
10.5.4. Accessing alerting rules for user-defined projects
To list alerting rules for a user-defined project, you must have been assigned the monitoring-rules-view
cluster role for the project.
Prerequisites
- You have enabled monitoring for user-defined projects.
-
You are logged in as a user that has the
monitoring-rules-view
cluster role for your project. -
You have installed the OpenShift CLI (
oc
).
Procedure
To list alerting rules in
<project>
:$ oc -n <project> get prometheusrule
To list the configuration of an alerting rule, run the following:
$ oc -n <project> get prometheusrule <rule> -o yaml
10.5.5. Listing alerting rules for all projects in a single view
As a dedicated-admin
, you can list alerting rules for core OpenShift Dedicated and user-defined projects together in a single view.
Prerequisites
-
You have access to the cluster as a user with the
dedicated-admin
role. -
You have installed the OpenShift CLI (
oc
).
Procedure
-
In the Administrator perspective, navigate to Observe
Alerting Alerting rules. Select the Platform and User sources in the Filter drop-down menu.
NoteThe Platform source is selected by default.
10.5.6. Removing alerting rules for user-defined projects
You can remove alerting rules for user-defined projects.
Prerequisites
- You have enabled monitoring for user-defined projects.
-
You are logged in as a user that has the
monitoring-rules-edit
cluster role for the project where you want to create an alerting rule. -
You have installed the OpenShift CLI (
oc
).
Procedure
To remove rule
<foo>
in<namespace>
, run the following:$ oc -n <namespace> delete prometheusrule <foo>
Additional resources
- See the Alertmanager documentation
10.6. Sending notifications to external systems
In OpenShift Dedicated 4, firing alerts can be viewed in the Alerting UI. Alerts are not configured by default to be sent to any notification systems. You can configure OpenShift Dedicated to send alerts to the following receiver types:
- PagerDuty
- Webhook
- Slack
- Microsoft Teams
Routing alerts to receivers enables you to send timely notifications to the appropriate teams when failures occur. For example, critical alerts require immediate attention and are typically paged to an individual or a critical response team. Alerts that provide non-critical warning notifications might instead be routed to a ticketing system for non-immediate review.
Checking that alerting is operational by using the watchdog alert
OpenShift Dedicated monitoring includes a watchdog alert that fires continuously. Alertmanager repeatedly sends watchdog alert notifications to configured notification providers. The provider is usually configured to notify an administrator when it stops receiving the watchdog alert. This mechanism helps you quickly identify any communication issues between Alertmanager and the notification provider.
10.6.1. Configuring different alert receivers for default platform alerts and user-defined alerts
You can configure different alert receivers for default platform alerts and user-defined alerts to ensure the following results:
- All default platform alerts are sent to a receiver owned by the team in charge of these alerts.
- All user-defined alerts are sent to another receiver so that the team can focus only on platform alerts.
You can achieve this by using the openshift_io_alert_source="platform"
label that is added by the Cluster Monitoring Operator to all platform alerts:
-
Use the
openshift_io_alert_source="platform"
matcher to match default platform alerts. -
Use the
openshift_io_alert_source!="platform"
or'openshift_io_alert_source=""'
matcher to match user-defined alerts.
This configuration does not apply if you have enabled a separate instance of Alertmanager dedicated to user-defined alerts.
10.6.2. Creating alert routing for user-defined projects
If you are a non-administrator user who has been given the alert-routing-edit
cluster role, you can create or edit alert routing for user-defined projects.
Prerequisites
- Alert routing has been enabled for user-defined projects.
-
You are logged in as a user that has the
alert-routing-edit
cluster role for the project for which you want to create alert routing. -
You have installed the OpenShift CLI (
oc
).
Procedure
-
Create a YAML file for alert routing. The example in this procedure uses a file called
example-app-alert-routing.yaml
. Add an
AlertmanagerConfig
YAML definition to the file. For example:apiVersion: monitoring.coreos.com/v1beta1 kind: AlertmanagerConfig metadata: name: example-routing namespace: ns1 spec: route: receiver: default groupBy: [job] receivers: - name: default webhookConfigs: - url: https://example.org/post
NoteFor user-defined alerting rules, user-defined routing is scoped to the namespace in which the resource is defined. For example, a routing configuration defined in the
AlertmanagerConfig
object for namespacens1
only applies toPrometheusRules
resources in the same namespace.- Save the file.
Apply the resource to the cluster:
$ oc apply -f example-app-alert-routing.yaml
The configuration is automatically applied to the Alertmanager pods.
10.7. Configuring Alertmanager to send notifications
You can configure Alertmanager to send notifications by editing the alertmanager-user-workload
secret for user-defined alerts.
All features of a supported version of upstream Alertmanager are also supported in an OpenShift Alertmanager configuration. To check all the configuration options of a supported version of upstream Alertmanager, see Alertmanager configuration.
10.7.1. Configuring notifications for user-defined alerts
If you have enabled a separate instance of Alertmanager that is dedicated to user-defined alert routing, you can customize where and how the instance sends notifications by editing the alertmanager-user-workload
secret in the openshift-user-workload-monitoring
namespace.
Prerequisites
-
You have access to the cluster as a user with the
dedicated-admin
role. -
You have installed the OpenShift CLI (
oc
).
Procedure
Print the currently active Alertmanager configuration into the file
alertmanager.yaml
:$ oc -n openshift-user-workload-monitoring get secret alertmanager-user-workload --template='{{ index .data "alertmanager.yaml" }}' | base64 --decode > alertmanager.yaml
Edit the configuration in
alertmanager.yaml
:route: receiver: Default group_by: - name: Default routes: - matchers: - "service = prometheus-example-monitor" 1 receiver: <receiver> 2 receivers: - name: Default - name: <receiver> <receiver_configuration> 3
Apply the new configuration in the file:
$ oc -n openshift-user-workload-monitoring create secret generic alertmanager-user-workload --from-file=alertmanager.yaml --dry-run=client -o=yaml | oc -n openshift-user-workload-monitoring replace secret --filename=-