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Variable Dependencies in Dashboards

OpenObserve Dashboards support dynamic filtering through variables. Variables enable users to interactively select values that filter and control what data is displayed in Panels.

Variable dependencies allow you to model parent-child relationships between variables. When a user selects a value for the parent variable, the child variable is updated to reflect only the relevant options associated with that selection.

This is useful when dealing with hierarchical data structures, where a logical relationship exists between fields, such as Kubernetes resources or application modules.

Example: Kubernetes Monitoring

Kubernetes Monitoring

Consider an observability scenario involving Kubernetes:

  • A namespace contains multiple pods.
  • Each pod hosts multiple containers.

To visualize and inspect logs at the container level, users must select:

  • A namespace,
  • Then a pod within that namespace,
  • And finally, a container within that pod.

This forms a three-level dependency chain:

Namespace > Pod > Container

In the above image:

  • $a_k8s_namespace_name (Namespace) is the top-level variable.
  • $b_k8s_pod_name (Pod) depends on the selected namespace.
  • $c_k8s_container_name (Container) depends on the selected pod.

How to Configure Variable Dependencies

Step 1: Navigate to Variables Configuration Page

  1. From the Dashboard toolbar, select Dashboard Settings. Dashboard Settings

  2. Click Add Variable. Add Variable

Step 2: Define the Parent Variable

This is the top-level variable that other variables will depend on. For instance, Kubernetes Namespace.
Configure the parent variable (k8s_namespace_name) in the Add Variable form:

  • Name: a_k8s_namespace_name
  • Type: Query Values
  • Stream Type: logs
  • Stream: default
  • Field: k8s_namespace_name
  • Filters: None

parent variable

Step 3: Configure the First-Level Dependent Variable

This variable uses the value of the parent variable to filter its own values. For instance, Kubernetes Pod.

Configure the dependent variable (k8s_pod_name) as shown below:

  • Name: b_k8s_pod_name
  • Type: Query Values
  • Field: k8s_pod_name

  • Filters:

    • Field: k8s_namespace_name
    • Value: $a_k8s_namespace_name

This setup ensures that only pods from the selected namespace are shown.
first-dependent-variable

Step 4: Configure the Second-Level Dependent Variable

This variable depends on the first-level dependent variables. For example, Kubernetes Container.
Configure the second-level dependent variable (k8s_container_name) as shown below:

  • Name: c_k8s_container_name
  • Type: Query Values
  • Field: k8s_container_name

  • Filters:

    • Field: k8s_pod_name
    • Value: $b_k8s_pod_name

second-dependent-variable

Note:

  • $ Prefix: Use the $ symbol when referencing other variables in the filter values.
  • Use the Hide on Dashboard toggle to hide the variable from the dashboard UI.

Variable Dependency Graph

The Variable Dependency Graph visually maps these relationships, showing how each variable is linked.
Variable Dependency Graph