Chapter 3. Configuring external alertmanager instances The OpenShift Container Platform monitoring stack includes a local Alertmanager instance that routes alerts from Prometheus. You can add external Alertmanager instances by configuring the cluster-monitoring-config config map in either the openshift-monitoring project or the user-workload-monitoring-config project. If you add the same external Alertmanager configuration for multiple clusters and disable the local instance for each cluster, you can then manage alert routing for multiple clusters by using a single external Alertmanager instance. Prerequisites You have installed the OpenShift CLI ( oc ). If you are configuring core OpenShift Container Platform monitoring components in the openshift-monitoring project : You have access to the cluster as a user with the cluster-admin cluster role. You have created the cluster-monitoring-config config map. If you are configuring components that monitor user-defined projects : You have access to the cluster as a user with the cluster-admin cluster role, or as a user with the user-workload-monitoring-config-edit role in the openshift-user-workload-monitoring project. A cluster administrator has enabled monitoring for user-defined projects. Procedure Edit the ConfigMap object. To configure additional Alertmanagers for routing alerts from core OpenShift Container Platform projects : Edit the cluster-monitoring-config config map in the openshift-monitoring project: USD oc -n openshift-monitoring edit configmap cluster-monitoring-config Add an additionalAlertmanagerConfigs: section under data/config.yaml/prometheusK8s . Add the configuration details for additional Alertmanagers in this section: apiVersion: v1 kind: ConfigMap metadata: name: cluster-monitoring-config namespace: openshift-monitoring data: config.yaml: | prometheusK8s: additionalAlertmanagerConfigs: - <alertmanager_specification> For <alertmanager_specification> , substitute authentication and other configuration details for additional Alertmanager instances. Currently supported authentication methods are bearer token ( bearerToken ) and client TLS ( tlsConfig ). The following sample config map configures an additional Alertmanager using a bearer token with client TLS authentication: apiVersion: v1 kind: ConfigMap metadata: name: cluster-monitoring-config namespace: openshift-monitoring data: config.yaml: | prometheusK8s: additionalAlertmanagerConfigs: - scheme: https pathPrefix: / timeout: "30s" apiVersion: v1 bearerToken: name: alertmanager-bearer-token key: token tlsConfig: key: name: alertmanager-tls key: tls.key cert: name: alertmanager-tls key: tls.crt ca: name: alertmanager-tls key: tls.ca staticConfigs: - external-alertmanager1-remote.com - external-alertmanager1-remote2.com To configure additional Alertmanager instances for routing alerts from user-defined projects : Edit the user-workload-monitoring-config config map in the openshift-user-workload-monitoring project: USD oc -n openshift-user-workload-monitoring edit configmap user-workload-monitoring-config Add a <component>/additionalAlertmanagerConfigs: section under data/config.yaml/ . Add the configuration details for additional Alertmanagers in this section: apiVersion: v1 kind: ConfigMap metadata: name: user-workload-monitoring-config namespace: openshift-user-workload-monitoring data: config.yaml: | <component>: additionalAlertmanagerConfigs: - <alertmanager_specification> For <component> , substitute one of two supported external Alertmanager components: prometheus or thanosRuler . For <alertmanager_specification> , substitute authentication and other configuration details for additional Alertmanager instances. Currently supported authentication methods are bearer token ( bearerToken ) and client TLS ( tlsConfig ). The following sample config map configures an additional Alertmanager using Thanos Ruler with a bearer token and client TLS authentication: apiVersion: v1 kind: ConfigMap metadata: name: user-workload-monitoring-config namespace: openshift-user-workload-monitoring data: config.yaml: | thanosRuler: additionalAlertmanagerConfigs: - scheme: https pathPrefix: / timeout: "30s" apiVersion: v1 bearerToken: name: alertmanager-bearer-token key: token tlsConfig: key: name: alertmanager-tls key: tls.key cert: name: alertmanager-tls key: tls.crt ca: name: alertmanager-tls key: tls.ca staticConfigs: - external-alertmanager1-remote.com - external-alertmanager1-remote2.com Save the file to apply the changes. The pods affected by the new configuration are automatically redeployed. 3.1. Attaching additional labels to your time series and alerts You can attach custom labels to all time series and alerts leaving Prometheus by using the external labels feature of Prometheus. Prerequisites If you are configuring core OpenShift Container Platform monitoring components : You have access to the cluster as a user with the cluster-admin cluster role. You have created the cluster-monitoring-config ConfigMap object. If you are configuring components that monitor user-defined projects : You have access to the cluster as a user with the cluster-admin cluster role, or as a user with the user-workload-monitoring-config-edit role in the openshift-user-workload-monitoring project. A cluster administrator has enabled monitoring for user-defined projects. You have installed the OpenShift CLI ( oc ). Procedure Edit the ConfigMap object: To attach custom labels to all time series and alerts leaving the Prometheus instance that monitors core OpenShift Container Platform projects : Edit the cluster-monitoring-config ConfigMap object in the openshift-monitoring project: USD oc -n openshift-monitoring edit configmap cluster-monitoring-config Define a map of labels you want to add for every metric under data/config.yaml : apiVersion: v1 kind: ConfigMap metadata: name: cluster-monitoring-config namespace: openshift-monitoring data: config.yaml: | prometheusK8s: externalLabels: <key>: <value> 1 1 Substitute <key>: <value> with a map of key-value pairs where <key> is a unique name for the new label and <value> is its value. Warning Do not use prometheus or prometheus_replica as key names, because they are reserved and will be overwritten. Do not use cluster or managed_cluster as key names. Using them can cause issues where you are unable to see data in the developer dashboards. For example, to add metadata about the region and environment to all time series and alerts, use the following example: apiVersion: v1 kind: ConfigMap metadata: name: cluster-monitoring-config namespace: openshift-monitoring data: config.yaml: | prometheusK8s: externalLabels: region: eu environment: prod Save the file to apply the changes. The new configuration is applied automatically. To attach custom labels to all time series and alerts leaving the Prometheus instance that monitors user-defined projects : Edit the user-workload-monitoring-config ConfigMap object in the openshift-user-workload-monitoring project: USD oc -n openshift-user-workload-monitoring edit configmap user-workload-monitoring-config Define a map of labels you want to add for every metric under data/config.yaml : apiVersion: v1 kind: ConfigMap metadata: name: user-workload-monitoring-config namespace: openshift-user-workload-monitoring data: config.yaml: | prometheus: externalLabels: <key>: <value> 1 1 Substitute <key>: <value> with a map of key-value pairs where <key> is a unique name for the new label and <value> is its value. Warning Do not use prometheus or prometheus_replica as key names, because they are reserved and will be overwritten. Do not use cluster or managed_cluster as key names. Using them can cause issues where you are unable to see data in the developer dashboards. Note In the openshift-user-workload-monitoring project, Prometheus handles metrics and Thanos Ruler handles alerting and recording rules. Setting externalLabels for prometheus in the user-workload-monitoring-config ConfigMap object will only configure external labels for metrics and not for any rules. For example, to add metadata about the region and environment to all time series and alerts related to user-defined projects, use the following example: apiVersion: v1 kind: ConfigMap metadata: name: user-workload-monitoring-config namespace: openshift-user-workload-monitoring data: config.yaml: | prometheus: externalLabels: region: eu environment: prod Save the file to apply the changes. The pods affected by the new configuration are automatically redeployed. Additional resources See Preparing to configure the monitoring stack for steps to create monitoring config maps. Enabling monitoring for user-defined projects

Commands:
oc -n openshift-monitoring edit configmap cluster-monitoring-config
apiVersion: v1 kind: ConfigMap metadata: name: cluster-monitoring-config namespace: openshift-monitoring data: config.yaml: | prometheusK8s: additionalAlertmanagerConfigs: - <alertmanager_specification>
apiVersion: v1 kind: ConfigMap metadata: name: cluster-monitoring-config namespace: openshift-monitoring data: config.yaml: | prometheusK8s: additionalAlertmanagerConfigs: - scheme: https pathPrefix: / timeout: "30s" apiVersion: v1 bearerToken: name: alertmanager-bearer-token key: token tlsConfig: key: name: alertmanager-tls key: tls.key cert: name: alertmanager-tls key: tls.crt ca: name: alertmanager-tls key: tls.ca staticConfigs: - external-alertmanager1-remote.com - external-alertmanager1-remote2.com
oc -n openshift-user-workload-monitoring edit configmap user-workload-monitoring-config
apiVersion: v1 kind: ConfigMap metadata: name: user-workload-monitoring-config namespace: openshift-user-workload-monitoring data: config.yaml: | <component>: additionalAlertmanagerConfigs: - <alertmanager_specification>
apiVersion: v1 kind: ConfigMap metadata: name: user-workload-monitoring-config namespace: openshift-user-workload-monitoring data: config.yaml: | thanosRuler: additionalAlertmanagerConfigs: - scheme: https pathPrefix: / timeout: "30s" apiVersion: v1 bearerToken: name: alertmanager-bearer-token key: token tlsConfig: key: name: alertmanager-tls key: tls.key cert: name: alertmanager-tls key: tls.crt ca: name: alertmanager-tls key: tls.ca staticConfigs: - external-alertmanager1-remote.com - external-alertmanager1-remote2.com
oc -n openshift-monitoring edit configmap cluster-monitoring-config
apiVersion: v1 kind: ConfigMap metadata: name: cluster-monitoring-config namespace: openshift-monitoring data: config.yaml: | prometheusK8s: externalLabels: <key>: <value> 1
apiVersion: v1 kind: ConfigMap metadata: name: cluster-monitoring-config namespace: openshift-monitoring data: config.yaml: | prometheusK8s: externalLabels: region: eu environment: prod
oc -n openshift-user-workload-monitoring edit configmap user-workload-monitoring-config
apiVersion: v1 kind: ConfigMap metadata: name: user-workload-monitoring-config namespace: openshift-user-workload-monitoring data: config.yaml: | prometheus: externalLabels: <key>: <value> 1
apiVersion: v1 kind: ConfigMap metadata: name: user-workload-monitoring-config namespace: openshift-user-workload-monitoring data: config.yaml: | prometheus: externalLabels: region: eu environment: prod