Chapter 1. Observability service

Observability service uses open source observability tools from community. View the following descriptions of the tools that are apart of the product observability service:

The following diagram shows the components of observability:

The components of the observability architecture include the following items:

Important: Do not use the local storage operator or a storage class that uses local volumes for persistent storage. You can lose data if the pod relaunched on a different node after a restart. When this happens, the pod can no longer access the local storage on the node. Be sure that you can access the persistent volumes of the receive and rules pods to avoid data loss.

When you install Red Hat Advanced Cluster Management the following persistent volumes (PV) must be created so that Persistent Volume Claims (PVC) can attach to it automatically. As a reminder, you must define a storage class in the MultiClusterObservability custom resource when there is no default storage class specified or you want to use a non-default storage class to host the PVs. It is recommended to use Block Storage, similar to what Prometheus uses. Also each replica of alertmanager, thanos-compactor, thanos-ruler, thanos-receive-default and thanos-store-shard must have its own PV. View the following table:

Note: The time series historical data is stored in object stores. Thanos uses object storage as the primary storage for metrics and metadata related to them. For more details about the object storage and downsampling, see Enabling observability service.

To learn more about observability and the integrated components, see the following topics:

By default, OpenShift Container Platform sends metrics to Red Hat using the Telemetry service. The acm_managed_cluster_info is available with Red Hat Advanced Cluster Management and is included with telemetry, but is not displayed on the Red Hat Advanced Cluster Management Observe environments overview dashboard.

View the following table of metric types that are supported by the framework:

Observability components require 2701mCPU and 11972Mi memory to install the observability service. The following table is a list of the pod capacity requests for five managed clusters with observability-addons enabled:

Enable the observability service by creating a MultiClusterObservability custom resource instance. Before you enable observability, see Observability pod capacity requests for more information.

Note:

Complete the following steps to enable the observability service:

Optionally, you can enable observability from the Red Hat OpenShift Container Platform console by creating a project named open-cluster-management-observability. Complete the following steps:

thanos --version

You can disable observability, which stops data collection on the Red Hat Advanced Cluster Management hub cluster.

spec:
  imagePullPolicy: Always
  imagePullSecret: multiclusterhub-operator-pull-secret
  observabilityAddonSpec: # The ObservabilityAddonSpec defines the global settings for all managed clusters which have observability add-on enabled
    enableMetrics: false #indicates the observability addon push metrics to hub server

When you remove the MultiClusterObservability custom resource, you are disabling and uninstalling the observability service. From the OpenShift Container Platform console navigation, select Operators > Installed Operators > Advanced Cluster Manager for Kubernetes. Remove the MultiClusterObservability custom resource.

Create custom rules for the observability installation by adding Prometheus recording rules and alerting rules to the observability resource.

To precalculate expensive expressions, use the recording rules abilities with Prometheus to create alert conditions and send notifications based on how you want to send an alert to an external service. The results are saved as a new set of time series. View the following examples to create a custom alert rule within the observability-thanos-rule-custom-rules config map:

To verify that the alert rules are functioning correctly, go to the Grafana dashboard, select the Explore page, and query ALERTS. The alert is only available in Grafana if you created the alert.

Add metrics to the metrics_list.yaml file to collect from managed clusters. Complete the following steps:

To update the retention for each observability component according to your need, add the advanced configuration section. Complete the following steps:

Dynamic metrics collection supports automatic metric collection based on certain conditions. By default, a single-node OpenShift cluster does not collect pod and container resource metrics. Once a single-node OpenShift cluster reaches a specific level of resource consumption, the defined granular metrics are collected dynamically. When the cluster resource consumption is consistently less than the threshold for a period of time, granular metric collection stops.

The metrics are collected dynamically based on the conditions on the managed cluster specified by a collection rule. Because these metrics are collected dynamically, the following Red Hat Advanced Cluster Management Grafana dashboards do not display any data. When a collection rule is activated and the corresponding metrics are collected, the following panels display data for the duration of the time that the collection rule is initiated:

By default, collection rules are evaluated continuously on managed clusters every 30 seconds, or at a specific time interval. The lowest value between the collection interval and time interval takes precedence. Once the collection rule condition persists for the duration specified by the for attribute, the collection rule starts and the metrics specified by the rule are automatically collected on the managed cluster. Metrics collection stops automatically after the collection rule condition no longer exists on the managed cluster, at least 15 minutes after it starts.

The collection rules are grouped together as a parameter section named collect_rules, where it can be enabled or disabled as a group. Red Hat Advanced Cluster Management installation includes the collection rule group, SNOResourceUsage with two default collection rules: HighCPUUsage and HighMemoryUsage. The HighCPUUsage collection rule begins when the node CPU usage exceeds 70%. The HighMemoryUsage collection rule begins if the overall memory utilization of the single-node OpenShift cluster exceeds 70% of the available node memory. Currently, the previously mentioned thresholds are fixed and cannot be changed. When a collection rule begins for more than the interval specified by the for attribute, the system automatically starts collecting the metrics that are specified in the dynamic_metrics section.

View the list of dynamic metrics that from the collect_rules section, in the following YAML file:

collect_rules:
  - group: SNOResourceUsage
    annotations:
      description: >
        By default, a {sno} cluster does not collect pod and container resource metrics. Once a {sno} cluster
        reaches a level of resource consumption, these granular metrics are collected dynamically.
        When the cluster resource consumption is consistently less than the threshold for a period of time,
        collection of the granular metrics stops.
    selector:
      matchExpressions:
        - key: clusterType
          operator: In
          values: ["{sno}"]
    rules:
    - collect: SNOHighCPUUsage
      annotations:
        description: >
          Collects the dynamic metrics specified if the cluster cpu usage is constantly more than 70% for 2 minutes
      expr: (1 - avg(rate(node_cpu_seconds_total{mode=\"idle\"}[5m]))) * 100 > 70
      for: 2m
      dynamic_metrics:
        names:
          - container_cpu_cfs_periods_total
          - container_cpu_cfs_throttled_periods_total
          - kube_pod_container_resource_limits
          - kube_pod_container_resource_requests
          - namespace_workload_pod:kube_pod_owner:relabel
          - node_namespace_pod_container:container_cpu_usage_seconds_total:sum_irate
          - node_namespace_pod_container:container_cpu_usage_seconds_total:sum_rate
    - collect: SNOHighMemoryUsage
      annotations:
        description: >
          Collects the dynamic metrics specified if the cluster memory usage is constantly more than 70% for 2 minutes
      expr: (1 - sum(:node_memory_MemAvailable_bytes:sum) / sum(kube_node_status_allocatable{resource=\"memory\"})) * 100 > 70
      for: 2m
      dynamic_metrics:
        names:
          - kube_pod_container_resource_limits
          - kube_pod_container_resource_requests
          - namespace_workload_pod:kube_pod_owner:relabel
        matches:
          - __name__="container_memory_cache",container!=""
          - __name__="container_memory_rss",container!=""
          - __name__="container_memory_swap",container!=""
          - __name__="container_memory_working_set_bytes",container!=""

A collect_rules.group can be disabled in the custom-allowlist as shown in the following example. When a collect_rules.group is disabled, metrics collection reverts to the previous behavior. These metrics are collected at regularly, specified intervals:

collect_rules:
  - group: -SNOResourceUsage

The data is only displayed in Grafana when the rule is initiated.

If your workload increases, increase the number of replicas of your observability pods. Navigate to the Red Hat OpenShift Container Platform console from your hub cluster. Locate the MultiClusterObservability custom resource, and update the replicas parameter value for the component where you want to change the replicas. Your updated YAML might resemble the following content:

spec:
   advanced:
      receive:
         replicas: 6

For more information about the parameters within the mco observability custom resource, see the Observability API documentation.

Increase and decrease the persistent volume and persistent volume claims to change the amount of storage in your storage class. Complete the following steps:

If you want to customize the OpenShift Container Platform route certification, you must add the routes in the alt_names section. To ensure your OpenShift Container Platform routes are accessible, add the following information: alertmanager.apps.<domainname>, observatorium-api.apps.<domainname>, rbac-query-proxy.apps.<domainname>.

For more details, see Replacing certificates for alertmanager route in the Governance documentation.

Note: Users are responsible for certificate rotations and updates.

You can configure secure connections with the observability object store by creating a Secret resource that contains the certificate authority and configuring the MultiClusterObservability custom resource. Complete the following steps:

Configure the proxy settings to allow the communications from the managed cluster to access the hub cluster through a HTTP and HTTPS proxy server. Typically, add-ons do not need any special configuration to support HTTP and HTTPS proxy servers between a hub cluster and a managed cluster. But if you enabled the observability add-on, you must complete the proxy configuration.

If your development needs change, you might need to disable the proxy setting for the observability add-ons you configured for the hub cluster and managed cluster. You can disable the proxy settings for the observability add-on at any time. Complete the following steps:

You can customize the Observatorium API and Alertmanager URLs that the managed cluster uses to communicate with the hub cluster to maintain all Red Hat Advanced Cluster Management functions when you use a load balancer or reserve proxy. To customize the URLs, complete the following steps:

To restrict metric access to specific namespaces within the cluster, use fine-grain role-based access control (RBAC). Using fine-grain RBAC, you can allow application teams to only view the metrics for the namespaces that you give them permission to access.

You must configure metric access control on the hub cluster for the users of that hub cluster. On this hub cluster, a ManagedCluster custom resource represents every managed cluster. To configure RBAC and to select the allowed namespaces, use the rules and action verbs specified in the ManagedCluster custom resources.

For example, you have an application named, my-awesome-app, and this application is on two different managed clusters, devcluster1 and devcluster2. Both clusters are in the AwesomeAppNS namespace. You have an admin user group named, my-awesome-app-admins, and you want to restrict this user group to only have access to metrics from only these two namespaces on the hub cluster.

In this example, to use fine-grain RBAC to restrict the user group access, complete the following steps:

After completing these steps, when the users in the my-awesome-app-admins log into the Grafana console, they have the following restrictions:

To set up different types of user access, define separate ClusterRoles and ClusterRoleBindings resources to represent the different managed clusters in the namespaces.

Observability provides an external API for metrics to be queried through the OpenShift route, rbac-query-proxy. See the following options to get your queries for the rbac-query-proxy route:

Complete the following steps to create proxy-byo-cert secrets for observability:

Export metrics to external endpoints, which support the Prometheus Remote-Write specification in real time. Complete the following steps to export metrics to external endpoints:

View the data from your managed clusters by accessing Grafana from the hub cluster. You can query specific alerts and add filters for the query.

For example, to explore the cluster_infrastructure_provider alert from a single-node OpenShift cluster, use the following query expression: cluster_infrastructure_provider{clusterType="SNO"}

Note: Do not set the ObservabilitySpec.resources.CPU.limits parameter if observability is enabled on single node managed clusters. When you set the CPU limits, it causes the observability pod to be counted against the capacity for your managed cluster. See the reference for Management Workload Partitioning in the Additional resources section.

Use Grafana dashboards to view hub cluster and managed cluster metrics. The data displayed in the Grafana alerts dashboard relies on alerts metrics, originating from managed clusters. The alerts metric does not affect managed clusters forwarding alerts to Red Hat Advanced Cluster Management alert manager on the hub cluster. Therefore, the metrics and alerts have distinct propagation mechanisms and follow separate code paths.

Even if you see data in the Grafana alerts dashboard, that does not guarantee that the managed cluster alerts are successfully forwarding to the Red Hat Advanced Cluster Management hub cluster alert manager. If the metrics are propagated from the managed clusters, you can view the data displayed in the Grafana alerts dashboard.

To use the Grafana dashboards for your development needs, complete the following:

grafana-cli

./generate-dashboard-configmap-yaml.sh "Your Dashboard Name"
Save dashboard <your-dashboard-name> to ./your-dashboard-name.yaml

oc apply -f demo-dashboard.yaml

./setup-grafana-dev.sh --clean
secret "grafana-dev-config" deleted
deployment.apps "grafana-dev" deleted
serviceaccount "grafana-dev" deleted
route.route.openshift.io "grafana-dev" deleted
persistentvolumeclaim "grafana-dev" deleted
oauthclient.oauth.openshift.io "grafana-proxy-client-dev" deleted
clusterrolebinding.rbac.authorization.k8s.io "open-cluster-management:grafana-crb-dev" deleted

Enable managed cluster labels to use them with Grafana dashboards. When observability is enabled in the hub cluster, the observability-managed-cluster-label-allowlist ConfigMap is created in the open-cluster-management-observability namespace. The ConfigMap contains a list of managed cluster labels maintained by the observabilty-rbac-query-proxy pod, to populate a list of label names to filter from within the ACM - Cluster Overview Grafana dashboard. By default, observability ignores a subset of labels in the observability-managed-cluster-label-allowlist ConfigMap.

When a cluster is imported into the managed cluster fleet or modified, the observability-rbac-query-proxy pod watches for any changes in reference to the managed cluster labels and automatically updates the observability-managed-cluster-label-allowlist ConfigMap to reflect the changes. The ConfigMap contains only unique label names, which are either included in the ignore_labels or labels list. Your observability-managed-cluster-label-allowlist ConfigMap might resemble the following YAML file:

data:
  managed_cluster.yaml: |
    ignore_labels: 1
      - clusterID
      - cluster.open-cluster-management.io/clusterset
      - feature.open-cluster-management.io/addon-application-manager
      - feature.open-cluster-management.io/addon-cert-policy-controller
      - feature.open-cluster-management.io/addon-cluster-proxy
      - feature.open-cluster-management.io/addon-config-policy-controller
      - feature.open-cluster-management.io/addon-governance-policy-framework
      - feature.open-cluster-management.io/addon-iam-policy-controller
      - feature.open-cluster-management.io/addon-observability-controller
      - feature.open-cluster-management.io/addon-search-collector
      - feature.open-cluster-management.io/addon-work-manager
      - installer.name
      - installer.namespace
      - local-cluster
      - name
    labels: 2
      - cloud
      - vendor

+ <1> Any label that is listed in the ignore_labels keylist of the ConfigMap is removed from the drop-down filter on the ACM - Clusters Overview Grafana dashboard. <2> The labels that are enabled are displayed in the drop-down filter on the ACM - Clusters Overview Grafana dashboard. The values are from the acm_managed_cluster_labels metric, depending on the label key value that is selected.

Continue reading how to use managed cluster labels in Grafana:

data:
  managed_cluster.yaml: |
    ignore_labels:
      - clusterID
      - cluster.open-cluster-management.io/clusterset
      - feature.open-cluster-management.io/addon-application-manager
      - feature.open-cluster-management.io/addon-cert-policy-controller
      - feature.open-cluster-management.io/addon-cluster-proxy
      - feature.open-cluster-management.io/addon-config-policy-controller
      - feature.open-cluster-management.io/addon-governance-policy-framework
      - feature.open-cluster-management.io/addon-iam-policy-controller
      - feature.open-cluster-management.io/addon-observability-controller
      - feature.open-cluster-management.io/addon-search-collector
      - feature.open-cluster-management.io/addon-work-manager
      - installer.name
      - installer.namespace
      - local-cluster
      - name
    labels:
      - cloud
      - department
      - vendor

data:
  managed_cluster.yaml: |
    ignore_labels:
      - clusterID
      - installer.name
      - installer.namespace
    labels:
      - cloud
      - vendor
      - local-cluster
      - name

enabled managedcluster labels: <label>

data:
  managed_cluster.yaml: |
    ignore_labels:
      - clusterID
      - installer.name
      - installer.namespace
      - local-cluster
      - name
    labels:
      - cloud
      - vendor

disabled managedcluster label: <label>

Integrate external messaging tools such as email, Slack, and PagerDuty to receive notifications from Alertmanager. You must override the alertmanager-config secret in the open-cluster-management-observability namespace to add integrations, and configure routes for Alertmanager. Complete the following steps to update the custom receiver rules:

Your changes are applied immediately after it is modified. For an example of Alertmanager, see prometheus/alertmanager.

After you enable observability, alerts from your OpenShift Container Platform managed clusters are automatically sent to the hub cluster. You can use the alertmanager-config YAML file to configure alerts with an external notification system.

View the following example of the alertmanager-config YAML file:

global:
  slack_api_url: '<slack_webhook_url>'

route:
  receiver: 'slack-notifications'
  group_by: [alertname, datacenter, app]

receivers:
- name: 'slack-notifications'
  slack_configs:
  - channel: '#alerts'
    text: 'https://internal.myorg.net/wiki/alerts/{{ .GroupLabels.app }}/{{ .GroupLabels.alertname }}'

If you want to configure a proxy for alert forwarding, add the following global entry to the alertmanager-config YAML file:

global:
  slack_api_url: '<slack_webhook_url>'
  http_config:
    proxy_url: http://****

metadata:
      annotations:
        mco-disable-alerting: "true"

Add alerts that you do not want to receive. You can silence alerts by the alert name, match label, or time duration. After you add the alert that you want to silence, an ID is created. Your ID for your silenced alert might resemble the following string, d839aca9-ed46-40be-84c4-dca8773671da.

Continue reading for ways to silence alerts:

Suppress Red Hat Advanced Cluster Management alerts across your clusters globally that are less severe. Suppress alerts by defining an inhibition rule in the alertmanager-config in the open-cluster-management-observability namespace.

An inhibition rule mutes an alert when there is a set of parameter matches that match another set of existing matchers. In order for the rule to take effect, both the target and source alerts must have the same label values for the label names in the equal list. Your inhibit_rules might resemble the following:

global:
  resolve_timeout: 1h
inhibit_rules:1
  - equal:
      - namespace
    source_match:2
      severity: critical
    target_match_re:
      severity: warning|info