[autoinstrumentation] Add node and pod ip env vars automatically (#2769)

* Add node and pod ip env vars automatically

* Fix tests

* Fix tests

* Fix tests

* Fix tests

* Fix tests

* Update changelog

.chloggen/include-node-ip-in-env-vars.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. collector, target allocator, auto-instrumentation, opamp, github action)
+component: instrumentation
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Instrumentation now automatically add node and pod ips as env vars `OTEL_NODE_IP` and `OTEL_POD_IP` to instrumented containers.
+
+# One or more tracking issues related to the change
+issues: [2769]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

README.md

@@ -263,6 +263,8 @@ The value for `sampler.type` is added to the `OTEL_TRACES_SAMPLER` environment v
 Valid values for `sampler.type` are defined by the [OpenTelemetry Specification for OTEL_TRACES_SAMPLER](https://opentelemetry.io/docs/concepts/sdk-configuration/general-sdk-configuration/#otel_traces_sampler).
 The value for `sampler.argument` is added to the `OTEL_TRACES_SAMPLER_ARG` environment variable. Valid values for `sampler.argument` will depend on the chosen sampler. See the [OpenTelemetry Specification for OTEL_TRACES_SAMPLER_ARG](https://opentelemetry.io/docs/concepts/sdk-configuration/general-sdk-configuration/#otel_traces_sampler_arg) for more details.
 
+The instrumentation will automatically inject `OTEL_NODE_IP` and `OTEL_POD_IP` environment variables should you need to reference either value in an endpoint.
+
 The above CR can be queried by `kubectl get otelinst`.
 
 Then add an annotation to a pod to enable injection. The annotation can be added to a namespace, so that all pods within

pkg/constants/env.go

@@ -33,7 +33,9 @@ const (
 
 	EnvPodName  = "OTEL_RESOURCE_ATTRIBUTES_POD_NAME"
 	EnvPodUID   = "OTEL_RESOURCE_ATTRIBUTES_POD_UID"
+	EnvPodIP    = "OTEL_POD_IP"
 	EnvNodeName = "OTEL_RESOURCE_ATTRIBUTES_NODE_NAME"
+	EnvNodeIP   = "OTEL_NODE_IP"
 
 	FlagApacheHttpd = "enable-apache-httpd-instrumentation"
 	FlagDotNet      = "enable-dotnet-instrumentation"