Observe the Mesh

Enable Sidecars in All Workloads

An Istio sidecar proxy connects a workload to the control plane and enables service mesh functionality.

Sidecars automatically collect metrics, access logs, and distributed traces — a major observability benefit of the mesh.

In Join the Mesh we injected a sidecar only into the control workload. The rest of the Travel Demo still lacks full mesh visibility.

1. Open Traffic Graph.
2. Select all three Travel Demo namespaces (travel-control, travel-portal, and travel-agency).
3. Note the Graph Type menu → if necessary, set to the default: Versioned App graph.
4. Note the Display menu → if necessary, enable Missing Sidecars (under Show Badges).

The control workload reports telemetry for its traffic, but visibility is incomplete because travel-portal and travel-agency workloads still lack sidecar proxies.

In Join the Mesh we enabled injection for a single workload on purpose. For the remaining namespaces, a common pattern is to label namespaces before rollout so Istio injects sidecars automatically.

Label the namespaces and restart the deployments:

kubectl label namespace travel-agency istio-injection=enabled
kubectl label namespace travel-portal istio-injection=enabled

kubectl rollout restart deploy -n travel-portal
kubectl rollout restart deploy -n travel-agency

Verify that workloads in all three demo namespaces have sidecars. Pods should show 2/2 ready (application + istio-proxy):

kubectl get pods -n travel-portal
kubectl get pods -n travel-agency

On the Workloads page, missing-sidecar badges should be gone for the restarted pods.

Return to Traffic Graph, keep all three Travel Demo namespaces selected, and refresh if needed. You should now see traffic across the full demo topology.

Graph Walkthrough

The graph provides a powerful set of graph features to visualize service mesh traffic.

In this section we use the graph to explore the Travel Demo and identify the busiest services.

1. Open Traffic Graph.
2. Select travel-control, travel-portal, and travel-agency.
3. Open Display → under Show Edge Labels, enable Traffic Distribution.

The mesh looks healthy, but note that the hotels service carries more load than other services in travel-agency.

1. Click the hotels service node.
2. In the summary panel on the right, open the Traces tab.
3. Select a trace to inspect.

Combining telemetry and tracing shows traces that start from a portal and involve multiple services, and others that call only the hotels service.

1. Right-click the travels application node. Right-click provides shortcuts to other Kiali pages.
2. Select Node Graph.

The graph focuses on the selected element so you can study one part of the topology in detail.

Application Details

Kiali provides detail views for applications, workloads, and services.

These views show structure, health, metrics, logs, traces, and Istio configuration for each component.

In this section we examine the main travels application in travel-agency.

1. Open Applications.
2. Select the travel-agency namespace.
3. Click the travels application.

An application groups workloads and services that share the same application label. Telemetry and tracing signals are grouped by application even when multiple workloads are involved.

At this point the travels application consists of a travels-v1 workload exposed through the travels service. Click the travels-v1 workload link in the application overview.

Open the Outbound Metrics tab on the travels-v1 workload.

The metrics tab shows charts built from Istio proxy telemetry. Expand the Request volume chart for a closer look:

Use Metrics Settings to change grouping and aggregation. Enable the spans checkbox to correlate metrics with tracing spans in the same chart.

In the context of the travels application, hotels request volume is higher than the other travel-agency services. Request duration looks normal, so the asymmetry is likely part of the application business logic rather than a performance problem.

The Logs tab combines application container logs with Istio sidecar proxy logs. Enable spans for a correlated view of logs and traces.

Two main business methods appear in the application logs: GetDestinations and GetTravelQuote.

GetDestinations issues a GET /hotels request without parameters (visible in the sidecar proxy log):

GetTravelQuote calls multiple downstream services with a specific city parameter:

As described in the Travel Demo design, an initial query returns available hotels before the user selects a destination and requests quotes from the other services — which explains the higher hotels utilization.

The hotels service handles more traffic than other travel-agency services. Next, use traces to see whether any step is slower than expected.

Open the Traces tab on travels-v1. Compare individual traces with the metrics histogram to judge whether a spike is unusual relative to average latency.

Click an interesting trace to see the trace details. Individual spans can be compared in more detail to pinpoint a slow step in a larger request flow.

Explore Further

This chapter focused on the graph and on the travels-v1 workload detail. The same observability tools are available throughout Kiali — browse the list pages and open any component to explore its detail view.

• Namespaces — open travel-portal or travel-agency for namespace health and shortcuts to filtered list views.
• Applications — compare travels in travel-agency with portal apps such as viaggi or voyages.
• Services — inspect hotels, which carried more load in the graph walkthrough.
• Workloads — open hotels-v1 or a portal workload and review the same tabs used here.
• Istio Config — browse VirtualServices, DestinationRules, and other Istio objects with validation and YAML.

Each detail page starts with an Overview tab (mini-graph, health, and links to related objects). Applications, services, and workloads also provide Traffic, Metrics, and Traces tabs. Workloads add Logs and Envoy, as you saw on travels-v1.

See Detail Views for a full description of each tab.

When you are ready to change mesh behavior — not only observe it — continue to Control the Mesh, where Kiali wizards help configure request routing and other traffic management scenarios.