shim: use a stable OpenTelemetry service name

Use containerd-shim-runc-v2 as the service name and report the supplied shim ID
and build version through service.instance.id and service.version. Preserve
inherited resource attributes while overriding the shim identity fields.

Test resource decoding and inherited attribute precedence with the OpenTelemetry
SDK.

Signed-off-by: Maksym Pavlenko <pavlenko.maksym@gmail.com>

cmd/containerd-shim-runc-v2/manager/manager_linux.go

@@ -24,10 +24,12 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"net/url"
 	"os"
 	"os/exec"
 	"path/filepath"
 	goruntime "runtime"
+	"strings"
 	"syscall"
 	"time"
 
@@ -105,7 +107,20 @@ func newCommand(ctx context.Context, id, containerdAddress, containerdTTRPCAddre
 	cmd := exec.Command(self, args...)
 	cmd.Dir = cwd
 	cmd.Env = append(os.Environ(), "GOMAXPROCS=4")
-	cmd.Env = append(cmd.Env, "OTEL_SERVICE_NAME=containerd-shim-"+id)
+	// Preserve inherited resource attributes, but override the daemon's identity.
+	// The OpenTelemetry SDK uses the last value for duplicate resource keys.
+	var attrs []string
+	if inherited := strings.TrimSpace(os.Getenv("OTEL_RESOURCE_ATTRIBUTES")); inherited != "" {
+		attrs = append(attrs, inherited)
+	}
+	attrs = append(attrs,
+		"service.instance.id="+url.PathEscape(id),
+		"service.version="+url.PathEscape(version.Version),
+	)
+	cmd.Env = append(cmd.Env,
+		"OTEL_SERVICE_NAME=containerd-shim-runc-v2",
+		"OTEL_RESOURCE_ATTRIBUTES="+strings.Join(attrs, ","),
+	)
 
 	cmd.SysProcAttr = &syscall.SysProcAttr{
 		Setpgid: true,

cmd/containerd-shim-runc-v2/manager/manager_linux_test.go

@@ -0,0 +1,84 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package manager
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/containerd/containerd/v2/pkg/namespaces"
+	"github.com/containerd/containerd/v2/version"
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+func TestNewCommandTracingResource(t *testing.T) {
+	for _, tc := range []struct {
+		name       string
+		inherited  string
+		attributes map[string]string
+	}{
+		{name: "empty"},
+		{name: "whitespace", inherited: "  "},
+		{
+			name:      "inherited",
+			inherited: "service.name=containerd,service.instance.id=daemon,service.version=old,service.namespace=runtime,host.name=node,custom.value=a%2Cb%3Dc%25",
+			attributes: map[string]string{
+				"service.namespace": "runtime",
+				"host.name":         "node",
+				"custom.value":      "a,b=c%",
+			},
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Setenv("OTEL_SERVICE_NAME", "containerd")
+			t.Setenv("OTEL_RESOURCE_ATTRIBUTES", tc.inherited)
+			ctx := namespaces.WithNamespace(context.Background(), "test-ns")
+			for _, id := range []string{"test-shim", "another-shim"} {
+				cmd, err := newCommand(ctx, id, "/containerd.sock", "/containerd.sock.ttrpc", false)
+				require.NoError(t, err)
+				// Environ applies exec.Cmd's duplicate-variable handling. Read the
+				// resulting resource with the SDK without using its cached default.
+				for _, entry := range cmd.Environ() {
+					key, value, _ := strings.Cut(entry, "=")
+					if key == "OTEL_SERVICE_NAME" || key == "OTEL_RESOURCE_ATTRIBUTES" {
+						t.Setenv(key, value)
+					}
+				}
+				res, err := resource.New(ctx, resource.WithFromEnv())
+				require.NoError(t, err)
+				attrs := res.Set()
+				for key, expected := range map[string]string{
+					"service.name":        "containerd-shim-runc-v2",
+					"service.instance.id": id,
+					"service.version":     version.Version,
+				} {
+					value, ok := attrs.Value(attribute.Key(key))
+					require.True(t, ok, key)
+					require.Equal(t, expected, value.AsString(), key)
+				}
+				for key, expected := range tc.attributes {
+					value, ok := attrs.Value(attribute.Key(key))
+					require.True(t, ok, key)
+					require.Equal(t, expected, value.AsString(), key)
+				}
+			}
+		})
+	}
+}