fix wrong Inst when having multi Inst

pkg/instrumentation/podmutator.go

@@ -428,6 +428,6 @@ func (pm *instPodMutator) selectInstrumentationInstanceFromNamespace(ctx context
 	case s > 1:
 		return nil, errMultipleInstancesPossible
 	default:
-		return &otelInsts.Items[0], nil
+		return &availableInstrument[0], nil
 	}
 }

tests/e2e-instrumentation/instrumentation-select/00-install-instrumentation-select.yaml

@@ -35,3 +35,41 @@ spec:
       value: "false"
     - name: SPLUNK_PROFILER_ENABLED
       value: "false"
+---
+apiVersion: opentelemetry.io/v1alpha1
+kind: Instrumentation
+metadata:
+  name: my-java-multi
+spec:
+  selector:
+    matchLabels:
+      app: my-java-multi
+  env:
+    - name: OTEL_TRACES_EXPORTER
+      value: otlp
+    - name: OTEL_EXPORTER_OTLP_ENDPOINT
+      value: http://localhost:4317
+    - name: OTEL_EXPORTER_OTLP_TIMEOUT
+      value: "20"
+    - name: OTEL_TRACES_SAMPLER
+      value: parentbased_traceidratio
+    - name: OTEL_TRACES_SAMPLER_ARG
+      value: "0.85"
+    - name: SPLUNK_TRACE_RESPONSE_HEADER_ENABLED
+      value: "true"
+  exporter:
+    endpoint: http://localhost:4317
+  propagators:
+    - jaeger
+    - b3
+  sampler:
+    type: parentbased_traceidratio
+    argument: "0.25"
+  java:
+    env:
+      - name: OTEL_JAVAAGENT_DEBUG
+        value: "true"
+      - name: OTEL_INSTRUMENTATION_JDBC_ENABLED
+        value: "false"
+      - name: SPLUNK_PROFILER_ENABLED
+        value: "false"

tests/e2e-instrumentation/instrumentation-select/01-assert-select-multi.yaml

@@ -0,0 +1,69 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  annotations:
+    instrumentation.opentelemetry.io/inject-java: "true"
+    sidecar.opentelemetry.io/inject: "true"
+  labels:
+    app: my-java-multi
+spec:
+  containers:
+  - env:
+    - name: OTEL_JAVAAGENT_DEBUG
+      value: "true"
+    - name: OTEL_INSTRUMENTATION_JDBC_ENABLED
+      value: "false"
+    - name: SPLUNK_PROFILER_ENABLED
+      value: "false"
+    - name: JAVA_TOOL_OPTIONS
+      value: ' -javaagent:/otel-auto-instrumentation-java/javaagent.jar'
+    - name: OTEL_TRACES_EXPORTER
+      value: otlp
+    - name: OTEL_EXPORTER_OTLP_ENDPOINT
+      value: http://localhost:4317
+    - name: OTEL_EXPORTER_OTLP_TIMEOUT
+      value: "20"
+    - name: OTEL_TRACES_SAMPLER
+      value: parentbased_traceidratio
+    - name: OTEL_TRACES_SAMPLER_ARG
+      value: "0.85"
+    - name: SPLUNK_TRACE_RESPONSE_HEADER_ENABLED
+      value: "true"
+    - name: OTEL_SERVICE_NAME
+      value: my-java-multi
+    - name: OTEL_RESOURCE_ATTRIBUTES_POD_NAME
+      valueFrom:
+        fieldRef:
+          apiVersion: v1
+          fieldPath: metadata.name
+    - name: OTEL_RESOURCE_ATTRIBUTES_NODE_NAME
+      valueFrom:
+        fieldRef:
+          apiVersion: v1
+          fieldPath: spec.nodeName
+    - name: OTEL_PROPAGATORS
+      value: jaeger,b3
+    - name: OTEL_RESOURCE_ATTRIBUTES
+    name: myapp
+    volumeMounts:
+    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
+      readOnly: true
+    - mountPath: /otel-auto-instrumentation-java
+      name: opentelemetry-auto-instrumentation-java
+  - args:
+    - --config=env:OTEL_CONFIG
+    name: otc-container
+  initContainers:
+  - name: opentelemetry-auto-instrumentation-java
+status:
+  containerStatuses:
+  - name: myapp
+    ready: true
+    started: true
+  - name: otc-container
+    ready: true
+    started: true
+  initContainerStatuses:
+  - name: opentelemetry-auto-instrumentation-java
+    ready: true
+  phase: Running

tests/e2e-instrumentation/instrumentation-select/01-install-app-select.yaml

@@ -55,3 +55,32 @@ spec:
             allowPrivilegeEscalation: false
             capabilities:
               drop: ["ALL"]
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: my-java-multi
+spec:
+  selector:
+    matchLabels:
+      app: my-java-multi
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        app: my-java-multi
+      annotations:
+        sidecar.opentelemetry.io/inject: "true"
+        instrumentation.opentelemetry.io/inject-java: "true"
+    spec:
+      securityContext:
+        runAsUser: 1000
+        runAsGroup: 3000
+        fsGroup: 3000
+      containers:
+        - name: myapp
+          image: ghcr.io/open-telemetry/opentelemetry-operator/e2e-test-app-java:main
+          securityContext:
+            allowPrivilegeEscalation: false
+            capabilities:
+              drop: ["ALL"]