mirror of https://github.com/hashicorp/consul
266 lines
8.5 KiB
Markdown
266 lines
8.5 KiB
Markdown
---
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layout: docs
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page_title: Service Mesh Distributed Tracing
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description: >-
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Distributed tracing tracks the path of a request as it traverses the service mesh. Consul supports distributed tracing for applications that have it implemented. Learn how to integrate tracing libraries in your application and configure Consul to participate in that tracing.
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---
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# Distributed Tracing
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Distributed tracing is a way to track and correlate requests across microservices. Distributed tracing must first
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be implemented in each application, it cannot be added by Consul. Once implemented in your applications, adding
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distributed tracing to Consul will add the sidecar proxies as spans in the request path.
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## Application Changes
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Consul alone cannot implement distributed tracing for your applications. Each application must propagate the required
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headers. Typically this is done using a tracing library such as:
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- https://github.com/opentracing/opentracing-go
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- https://github.com/DataDog/dd-trace-go
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- https://github.com/openzipkin/zipkin-go
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## Configuration
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Once your applications have been instrumented with a tracing library, you are ready to configure Consul to add sidecar
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proxy spans to the trace. Your eventual config will look something like:
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<CodeTabs tabs={[ "HCL", "Kubernetes YAML", "JSON" ]}>
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```hcl
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Kind = "proxy-defaults"
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Name = "global"
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Config {
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protocol = "http"
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envoy_tracing_json = <<EOF
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{
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"http":{
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"name":"envoy.tracers.zipkin",
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"typedConfig":{
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"@type":"type.googleapis.com/envoy.config.trace.v3.ZipkinConfig",
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"collector_cluster":"collector_cluster_name",
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"collector_endpoint_version":"HTTP_JSON",
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"collector_endpoint":"/api/v2/spans",
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"shared_span_context":false
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}
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}
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}
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EOF
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envoy_extra_static_clusters_json = <<EOF
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{
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"connect_timeout":"3.000s",
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"dns_lookup_family":"V4_ONLY",
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"lb_policy":"ROUND_ROBIN",
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"load_assignment":{
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"cluster_name":"collector_cluster_name",
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"endpoints":[
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{
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"lb_endpoints":[
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{
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"endpoint":{
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"address":{
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"socket_address":{
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"address":"collector-url",
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"port_value":9411,
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"protocol":"TCP"
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}
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}
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}
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}
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]
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}
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]
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},
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"name":"collector_cluster_name",
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"type":"STRICT_DNS"
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}
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EOF
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}
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```
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```yaml
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apiVersion: consul.hashicorp.com/v1alpha1
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kind: ProxyDefaults
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metadata:
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name: global
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spec:
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config:
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protocol: http
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envoy_tracing_json: |
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{
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"http":{
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"name":"envoy.tracers.zipkin",
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"typedConfig":{
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"@type":"type.googleapis.com/envoy.config.trace.v3.ZipkinConfig",
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"collector_cluster":"collector_cluster_name",
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"collector_endpoint_version":"HTTP_JSON",
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"collector_endpoint":"/api/v2/spans",
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"shared_span_context":false
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}
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}
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}
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envoy_extra_static_clusters_json: |
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{
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"connect_timeout":"3.000s",
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"dns_lookup_family":"V4_ONLY",
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"lb_policy":"ROUND_ROBIN",
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"load_assignment":{
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"cluster_name":"collector_cluster_name",
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"endpoints":[
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{
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"lb_endpoints":[
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{
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"endpoint":{
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"address":{
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"socket_address":{
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"address":"collector-url",
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"port_value":9411,
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"protocol":"TCP"
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}
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}
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}
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}
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]
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}
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]
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},
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"name":"collector_cluster_name",
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"type":"STRICT_DNS"
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}
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```
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```json
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{
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"Kind": "ProxyDefaults",
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"Name": "global",
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"Config": {
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"protocol": "http",
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"envoy_tracing_json": "{\"http\":{\"name\":\"envoy.tracers.zipkin\",\"typedConfig\":{\"@type\":\"type.googleapis.com/envoy.config.trace.v3.ZipkinConfig\",\"collector_cluster\":\"collector_cluster_name\",\"collector_endpoint_version\":\"HTTP_JSON\",\"collector_endpoint\":\"/api/v2/spans\",\"shared_span_context\":false}}}",
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"envoy_extra_static_clusters_json": "{\"connect_timeout\":\"3.000s\",\"dns_lookup_family\":\"V4_ONLY\",\"lb_policy\":\"ROUND_ROBIN\",\"load_assignment\":{\"cluster_name\":\"collector_cluster_name\",\"endpoints\":[{\"lb_endpoints\":[{\"endpoint\":{\"address\":{\"socket_address\":{\"address\":\"collector-url\",\"port_value\":9411,\"protocol\":\"TCP\"}}}}]}]},\"name\":\"collector_cluster_name\",\"type\":\"STRICT_DNS\"}"
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}
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}
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```
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</CodeTabs>
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-> **NOTE:** This example uses a [proxy defaults](/consul/docs/connect/config-entries/proxy-defaults) config entry which will apply to all proxies
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but you can also apply this config in the
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[proxy service registration](/consul/docs/connect/registration/service-registration#proxy-parameters) (not supported on Kubernetes).
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Within the config there are two keys you need to customize:
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1. [`envoy_tracing_json`](/consul/docs/connect/proxies/envoy#envoy_tracing_json): Sets the tracing configuration for your specific tracing type.
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See the [Envoy tracers documentation](https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/trace/trace) for your
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specific collector's configuration. This configuration will reference the cluster name defined in `envoy_extra_static_clusters_json`.
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1. [`envoy_extra_static_clusters_json`](/consul/docs/connect/proxies/envoy#envoy_extra_static_clusters_json): Defines the address
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of your tracing collector where Envoy will send its spans. In this example the URL was `collector-url:9411`.
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## Applying the configuration
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This configuration only applies when proxies are _restarted_ since it changes the _bootstrap_ config for Envoy
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which can only be applied on startup. This means you must restart all your proxies for changes to this
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config to take effect.
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-> **Note:** On Kubernetes this is a matter of restarting your deployments, e.g. `kubectl rollout restart deploy/deploy-name`.
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## Considerations
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1. Distributed tracing is only supported for HTTP and gRPC services. You must specify the protocol either globally
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via a proxy defaults config entry:
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<CodeTabs tabs={[ "HCL", "Kubernetes YAML", "JSON" ]}>
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```hcl
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Kind = "proxy-defaults"
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Name = "global"
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Config {
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protocol = "http"
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}
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```
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```yaml
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apiVersion: consul.hashicorp.com/v1alpha1
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kind: ProxyDefaults
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metadata:
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name: global
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spec:
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config:
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protocol: http
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```
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```json
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{
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"Kind": "proxy-defaults",
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"Name": "global",
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"Config": {
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"protocol": "http"
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}
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}
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```
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</CodeTabs>
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Or via a service defaults config entry for each service:
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<CodeTabs tabs={[ "HCL", "Kubernetes YAML", "JSON" ]}>
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```hcl
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Kind = "service-defaults"
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Name = "service-name"
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Protocol = "http"
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```
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```yaml
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apiVersion: consul.hashicorp.com/v1alpha1
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kind: ServiceDefaults
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metadata:
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name: service-name
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spec:
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protocol: http
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```
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```json
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{
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"Kind": "service-defaults",
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"Name": "service-name",
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"Protocol": "http"
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}
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```
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</CodeTabs>
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1. Requests through [Ingress Gateways](/consul/docs/connect/gateways/ingress-gateway) will not be traced unless the header
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`x-client-trace-id: 1` is set (see [hashicorp/consul#6645](https://github.com/hashicorp/consul/issues/6645)).
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1. Consul's proxies do not currently support [OpenTelemetry](https://opentelemetry.io/) spans, as Envoy has not
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[fully implemented](https://github.com/envoyproxy/envoy/issues/9958) it. Instead, you can add
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OpenTelemetry libraries to your application to emit spans for other
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[tracing protocols](https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/observability/tracing)
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supported by Envoy, such as Zipkin or Jaeger.
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1. Tracing is only supported with Envoy proxies, not the built-in proxy.
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1. When configuring the Zipkin tracer in `envoy_tracing_json`, set [`trace_id_128bit`](https://www.envoyproxy.io/docs/envoy/v1.21.0/api-v3/config/trace/v3/zipkin.proto#envoy-v3-api-field-config-trace-v3-zipkinconfig-trace-id-128bit) to `true` if your application is configured to generate 128-bit trace IDs. For example:
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<CodeBlockConfig highlight="10">
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```json
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{
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"http": {
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"name": "envoy.tracers.zipkin",
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"typedConfig": {
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"@type": "type.googleapis.com/envoy.config.trace.v3.ZipkinConfig",
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"collector_cluster": "zipkin",
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"collector_endpoint_version": "HTTP_JSON",
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"collector_endpoint": "/api/v2/spans",
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"shared_span_context": false,
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"trace_id_128bit": true
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}
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}
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}
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```
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</CodeBlockConfig>
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