Add OpenTelemetry tab to GCP metrics

docs/shipping/GCP/gcp-cloud-monitoring.md

@@ -29,10 +29,288 @@ Give your logs some time to get from your system to ours, and then open [Open Se
 
 ## Metrics
 
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+<Tabs>
+  <TabItem value="telegraf" label="Telegraf" default>
+
 {@include: ../../_include/general-shipping/gcp-metrics.md}
 
 For this integration, the telemetry list needs to include `monitoring.googleapis.com`.
 
 ### Check Logz.io for your metrics
 
 Give your data some time to get from your system to ours, then log in to your Logz.io Metrics account, and open [the Logz.io Metrics tab](https://app.logz.io/#/dashboard/metrics/).
+
+  </TabItem>
+  <TabItem value="opentelemetry" label="OpenTelemetry">
+
+Use the OpenTelemetry Collector or the Logz.io Telemetry Helm chart and configure `googlecloudmonitoring` receiver to pull metrics from Google Cloud Monitoring and ship them to Logz.io via Prometheus Remote Write.
+
+<Tabs>
+  <TabItem value="local" label="Local/Native (Collector)">
+
+Run the OpenTelemetry Collector on a host (VM, server, or workstation) to pull metrics from Google Cloud Monitoring using your service account credentials and forward them to Logz.io.
+
+### Prerequisites
+
+- OpenTelemetry Collector Contrib v0.131.0+ installed on your host
+- Google Cloud project with Monitoring enabled
+- Service account JSON key with `roles/monitoring.viewer`
+- Logz.io Metrics shipping token and listener host
+
+### Step 1: Install OpenTelemetry Collector
+
+Download the OpenTelemetry Collector Contrib binary for your operating system from the [releases page](https://github.com/open-telemetry/opentelemetry-collector-contrib/releases).
+
+For example, on Linux:
+
+```bash
+# Download the latest version (replace with actual version)
+wget https://github.com/open-telemetry/opentelemetry-collector-contrib/releases/download/v0.131.0/otelcol-contrib_0.131.0_linux_amd64.tar.gz
+tar -xzf otelcol-contrib_0.131.0_linux_amd64.tar.gz
+chmod +x otelcol-contrib
+```
+
+On macOS:
+
+```bash
+# Download for macOS
+wget https://github.com/open-telemetry/opentelemetry-collector-contrib/releases/download/v0.131.0/otelcol-contrib_0.131.0_darwin_amd64.tar.gz
+tar -xzf otelcol-contrib_0.131.0_darwin_amd64.tar.gz
+chmod +x otelcol-contrib
+```
+
+### Step 2: Prepare credentials
+
+Ensure you have a Google Cloud service account and JSON key as described above. Set the environment variable so the Collector can authenticate:
+
+```bash
+export GOOGLE_APPLICATION_CREDENTIALS=/path/to/your/gcp-credentials.json
+```
+
+### Step 3: Create the Collector configuration
+
+Create `config.yaml` with the following content:
+Make sure to replace `<<YOUR-GCP-PROJECT-ID>>` with your Google Cloud Platform Project ID.
+
+```yaml
+receivers:
+  googlecloudmonitoring/project_1:
+    collection_interval: 2m
+    project_id: "<<YOUR-GCP-PROJECT-ID>>"
+    metrics_list:
+      - metric_descriptor_filter: "metric.type = starts_with(\"compute.googleapis.com\")"
+  googlecloudmonitoring/project_2:
+    collection_interval: 2m
+    project_id: "<<YOUR-GCP-PROJECT-ID>>"
+    metrics_list:
+      - metric_name: "connectors.googleapis.com/flex/instance/cpu/usage_time"
+processors:
+  batch: {}
+
+exporters:
+  prometheusremotewrite:
+    endpoint: https://<<LISTENER-HOST>>:8053
+    headers:
+      Authorization: Bearer <<PROMETHEUS-METRICS-SHIPPING-TOKEN>>
+
+service:
+  pipelines:
+    metrics:
+      receivers: [googlecloudmonitoring/project_1, googlecloudmonitoring/project_2]
+      processors: [batch]
+      exporters: [prometheusremotewrite]
+```
+
+{@include: ../../_include/general-shipping/replace-placeholders-prometheus.html}
+
+Optional metric filters under `metrics_list`:
+
+```yaml
+- metric_descriptor_filter: "metric.type = starts_with(\"cloudsql.googleapis.com\")"
+- metric_descriptor_filter: "metric.type = starts_with(\"bigquery.googleapis.com\")"
+- metric_descriptor_filter: "metric.type = starts_with(\"storage.googleapis.com\")"
+- metric_descriptor_filter: "metric.type = \"compute.googleapis.com/instance/cpu/utilization\""
+- metric_name: "connectors.googleapis.com/flex/instance/cpu/usage_time"
+```
+
+### Step 4: Run the Collector
+
+```bash
+./otelcol-contrib --config ./config.yaml | cat
+```
+
+Make sure the process inherits `GOOGLE_APPLICATION_CREDENTIALS`.
+
+### Verify
+
+- Look for exporter logs without errors
+- Confirm metrics appear under your Logz.io account after a few minutes
+
+### Troubleshooting
+
+- Credentials path not set or incorrect in `GOOGLE_APPLICATION_CREDENTIALS`
+- Missing `roles/monitoring.viewer` on the service account
+- Incorrect `project_id` or overly restrictive `metrics_list`
+- Network egress blocked to Logz.io metrics endpoint
+
+### Check Logz.io for your metrics
+
+Give your data some time to get from your system to ours, then open [the Logz.io Metrics tab](https://app.logz.io/#/dashboard/metrics/).
+
+  </TabItem>
+  <TabItem value="kubernetes" label="Kubernetes (Helm)" default>
+
+### Prerequisites
+
+- Kubernetes cluster with Helm installed
+- kubectl configured to access your cluster
+- Google Cloud project with Monitoring enabled
+- Logz.io account with a metrics shipping token
+
+### Step 1: Create Google Cloud Service Account
+
+Grant the service account the Monitoring Viewer role (`roles/monitoring.viewer`) and create a JSON key.
+
+Using Google Cloud Console:
+
+- Go to Google Cloud Console > IAM & Admin > Service Accounts > Create Service Account
+- Give it a name/description and click Create and Continue
+- Grant role: Monitoring Viewer (`roles/monitoring.viewer`)
+- Go to the Keys tab > Add key > Create new key > JSON, then download the key file.
+
+Alternative using gcloud CLI:
+
+```bash
+export PROJECT_ID="your-project-id"
+
+gcloud iam service-accounts create otel-gcp-metrics-logzio-sa \
+  --display-name="OpenTelemetry GCP Metrics Service Account" \
+  --description="Service account for collecting GCP metrics via OpenTelemetry" \
+  --project=$PROJECT_ID
+
+gcloud projects add-iam-policy-binding $PROJECT_ID \
+  --member="serviceAccount:otel-gcp-metrics-logzio-sa@$PROJECT_ID.iam.gserviceaccount.com" \
+  --role="roles/monitoring.viewer"
+
+gcloud iam service-accounts keys create gcp-credentials.json \
+  --iam-account=otel-gcp-metrics-logzio-sa@$PROJECT_ID.iam.gserviceaccount.com \
+  --project=$PROJECT_ID
+```
+
+### Step 2: Create Kubernetes Secret
+
+```bash
+kubectl create namespace monitoring --dry-run=client -o yaml | kubectl apply -f -
+
+kubectl create secret generic google-cloud-credentials \
+  --from-file=your-credentials.json=/path/to/your/gcp-credentials.json \
+  -n monitoring
+
+kubectl get secret google-cloud-credentials -n monitoring | cat
+```
+
+### Step 3: Configure Helm values
+
+Create or update your `values.yaml` for the `logzio-monitoring` umbrella chart (nest under `logzio-k8s-telemetry`):
+Make sure to replace `<<YOUR-GCP-PROJECT-ID>>` with your Google Cloud Platform Project ID.
+
+```yaml
+logzio-k8s-telemetry:
+  global:
+    logzioMetricsToken: "your-logzio-metrics-token"
+    env_id: "your-environment-name"
+    customMetricsEndpoint: "https://listener.logz.io:8053"  # Optional override
+
+  metrics:
+    enabled: true
+
+  collector:
+    mode: standalone  # or daemonset
+
+  extraEnvs:
+    - name: GOOGLE_APPLICATION_CREDENTIALS
+      value: /var/secrets/google/your-credentials.json  # must match filename in the secret
+
+  secretMounts:
+    - name: google-cloud-credentials
+      secretName: google-cloud-credentials
+      mountPath: /var/secrets/google
+      readOnly: true
+
+
+  metricsConfig: # or daemonsetConfig
+    receivers:
+      googlecloudmonitoring/project_1:
+        collection_interval: 2m
+        project_id: "<<YOUR-GCP-PROJECT-ID>>"
+        metrics_list:
+          - metric_descriptor_filter: "metric.type = starts_with(\"compute.googleapis.com\")"
+      googlecloudmonitoring/project_2:
+        collection_interval: 2m
+        project_id: "<<YOUR-GCP-PROJECT-ID>>"
+        metrics_list:
+          - metric_name: "connectors.googleapis.com/flex/instance/cpu/usage_time"            
+    service:
+      pipelines:
+        metrics/googlecloudmonitoring:
+        # existing receivers in your pipeline.
+          receivers:
+            - googlecloudmonitoring/project_1
+            - googlecloudmonitoring/project_2
+          processors:
+            - attributes/env_id
+            - batch
+          exporters:
+            - prometheusremotewrite/infrastructure
+```
+
+Metric filter examples you can add under `metrics_list`:
+
+```yaml
+- metric_descriptor_filter: "metric.type = starts_with(\"cloudsql.googleapis.com\")"
+- metric_descriptor_filter: "metric.type = starts_with(\"bigquery.googleapis.com\")"
+- metric_descriptor_filter: "metric.type = starts_with(\"storage.googleapis.com\")"
+- metric_descriptor_filter: "metric.type = \"compute.googleapis.com/instance/cpu/utilization\""
+- metric_name: "connectors.googleapis.com/flex/instance/cpu/usage_time"
+```
+
+### Step 4: Deploy the chart
+
+```bash
+helm repo add logzio-helm https://logzio.github.io/logzio-helm && helm repo update
+helm upgrade --install logzio-monitoring logzio-helm/logzio-monitoring \
+  -n monitoring \
+  --create-namespace \
+  -f your-values.yaml
+```
+
+### Verify
+
+```bash
+kubectl get pods -n monitoring | cat
+kubectl logs -n monitoring -l app.kubernetes.io/name=otel-collector --tail=50 | cat
+
+POD_NAME=$(kubectl get pods -n monitoring -l component=logzio-telemetry-collector-standalone -o jsonpath='{.items[0].metadata.name}')
+kubectl exec -n monitoring $POD_NAME -- ls -la /var/secrets/google/ | cat
+kubectl exec -n monitoring $POD_NAME -- env | grep GOOGLE_APPLICATION_CREDENTIALS | cat
+```
+
+### Troubleshooting
+
+- Credentials filename/path mismatch in secret vs `GOOGLE_APPLICATION_CREDENTIALS`
+- Missing `roles/monitoring.viewer` on the service account
+- Wrong `project_id` or metric filters return no data
+- Collector crash loops due to invalid misconfigured `metricsConfig` / `daemonsetConfig`
+
+### Check Logz.io for your metrics
+
+Give your data some time to get from your system to ours, then open [the Logz.io Metrics tab](https://app.logz.io/#/dashboard/metrics/).
+
+  </TabItem>
+</Tabs>
+
+  </TabItem>
+</Tabs>