[chore][journaldreceiver] Add Docker and Kubernetes examples

receiver/journaldreceiver/README.md

@@ -182,7 +182,7 @@ The user running the collector must have enough permissions to access the journa
 
 When running in a containerized environment, differences in the systemd version running on the host and on the container may prevent access to logs due to different features and configurations (e.g. zstd compression, keyed hash etc).
 
-### Docker
+### Docker & Kubernetes
 
 When running otelcol in a container, note that:
 
@@ -192,6 +192,8 @@ When running otelcol in a container, note that:
 
 Please note that *the official otelcol images do not contain the journald binary*; you will need to create your custom image or find one that does.
 
+There is a simple example with a step-by-step, including a `Dockerfile` in [`examples/container`](examples/container/README.md).
+
 ### Linux packaging
 
 When installing otelcol as a linux package, you will most likely need to add the `otelcol-contrib` or `otel` user to the `systemd-journal` group. The exact user and group might vary depending on your package and linux distribution of choice.
@@ -203,7 +205,3 @@ sudo su -s /bin/bash -c 'journalctl --lines 5' otelcol-contrib
 ```
 
 if the permissions are set correctly you will see some logs, otherwise a clear error message.
-
-### Kubernetes
-
-See the instructions for [Docker](#Docker) and adapt according to your Kubernetes distribution and node OS.

receiver/journaldreceiver/examples/container/Dockerfile

@@ -0,0 +1,17 @@
+FROM debian:13-slim
+
+ARG OTEL_COL_VERSION=0.136.0
+
+WORKDIR /opt
+
+RUN apt update && \
+    apt install -y systemd wget && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
+
+RUN wget "https://github.com/open-telemetry/opentelemetry-collector-releases/releases/download/v${OTEL_COL_VERSION}/otelcol-contrib_${OTEL_COL_VERSION}_linux_amd64.tar.gz" && \
+    tar -xzf "otelcol-contrib_${OTEL_COL_VERSION}_linux_amd64.tar.gz"
+COPY otelcol-config.yml /opt/otelcol-config.yml
+
+ENTRYPOINT ["/opt/otelcol-contrib"]
+CMD ["--config", "/opt/otelcol-config.yml"]

receiver/journaldreceiver/examples/container/README.md

@@ -0,0 +1,89 @@
+# Running journaldreceiver in Docker and Kubernetes
+The first step to run the journaldreceiver in Docker or Kubernetes is
+to build a Docker image containing the Opentelemetry Collector and the
+`journalctl` binary. The following `Dockerfile` can be used as a
+starting point.
+
+```dockerfile
+FROM debian:13-slim
+
+ARG OTEL_COL_VERSION=0.136.0
+
+WORKDIR /opt
+
+RUN apt update && \
+    apt install -y systemd wget && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
+
+RUN wget "https://github.com/open-telemetry/opentelemetry-collector-releases/releases/download/v${OTEL_COL_VERSION}/otelcol-contrib_${OTEL_COL_VERSION}_linux_amd64.tar.gz" && \
+    tar -xzf "otelcol-contrib_${OTEL_COL_VERSION}_linux_amd64.tar.gz"
+COPY otelcol-config.yml /opt/otelcol-config.yml
+
+ENTRYPOINT ["/opt/otelcol-contrib"]
+CMD ["--config", "/opt/otelcol-config.yml"]
+```
+
+To build the image setting the Collector version at build time you can
+use:
+```sh
+docker build --build-arg OTEL_COL_VERSION=0.136.0 -t otel-col-journald .
+```
+
+You can check the version of the Collector by running:
+```sh
+docker run --rm -it otel-col-journald:latest --version
+```
+
+To check the version of `journalctl` installed, run:
+```
+docker run --rm -it --entrypoint journalctl otel-col-journald:latest --version
+```
+
+## Docker
+You can use the provided `otelcol-config.yml` to test the
+journaldreceiver. If your journal logs are on `/var/log/journal`, run:
+
+```sh
+docker run --rm --mount type=bind,source=/var/log/journal,target=/opt/journal,ro otel-col-journald
+```
+
+You will see the journal logs from your machine being displayed by the
+debug exporter.
+
+## Kubernetes
+The journaldreceiver can be used to ingest the node logs from a
+Kubernets cluster, it is a very similar process as running it in
+Docker: build the image, deploy a daemonset giving it access to the
+journal folder on the nodes.
+
+For this example we will use [Kind](https://kind.sigs.k8s.io/) to spin
+up a Kubernetes cluster using Docker container nodes.
+
+First build the docker image as shown above, then start the kind cluster:
+```sh
+kind create cluster
+```
+
+Load the image into the cluster:
+```
+kind load docker-image otel-col-journald:latest
+```
+
+Then deploy the Collector:
+```
+% kubectl apply -f manifest.yml
+configmap/otel-config created
+daemonset.apps/otel-collector created
+```
+
+Wait for the pod to be ready:
+```
+% kubectl get pods
+NAME                   READY   STATUS    RESTARTS   AGE
+otel-collector-k4fhv   1/1     Running   0          29s
+```
+Follow the pod logs to see the journaldreceiver working:
+```
+kubectl logs -f otel-collector-k4fhv # adjust the pod name
+```

receiver/journaldreceiver/examples/container/manifest.yml

@@ -0,0 +1,56 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: otel-config
+data:
+  otel-config.yml: |
+    receivers:
+      journald:
+        directory: /opt/journal
+
+    exporters:
+      debug:
+        verbosity: normal
+
+    service:
+      pipelines:
+        logs:
+          receivers: [journald]
+          exporters: [debug]
+---
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: otel-collector
+  labels:
+    app: otel-collector
+spec:
+  selector:
+    matchLabels:
+      app: otel-collector
+  template:
+    metadata:
+      labels:
+        app: otel-collector
+    spec:
+      containers:
+      - name: otel-collector
+        image: otel-col-journald:latest
+        # Image is already loaded in the cluster, no need to pull it
+        # because pulling will fail because it has not been published.
+        imagePullPolicy: Never 
+        volumeMounts:
+        - name: otel-config-volume
+          mountPath: /opt/otelcol-config.yaml
+          subPath: otel-config.yml
+        - name: journal-volume
+          mountPath: /opt/journal
+          readOnly: true
+      volumes:
+      - name: otel-config-volume
+        configMap:
+          name: otel-config
+      - name: journal-volume
+        hostPath:
+          path: /run/log/journal/
+          type: Directory

receiver/journaldreceiver/examples/container/otelcol-config.yml

@@ -0,0 +1,13 @@
+receivers:
+  journald:
+    directory: /opt/journal
+
+exporters:
+  debug:
+    verbosity: normal
+
+service:
+  pipelines:
+    logs:
+      receivers: [journald]
+      exporters: [debug]