Migrate to Grafana Alloy as the recommended replacement for log forwarding.

Changes:
- Add alloy/config.alloy.example configuration
- Move promtail/run.sh to alloy/run.sh
- Update logging.yml to use Alloy
- Remove promtail/config.yml.example

Author: apham0001

alloy/config.alloy.example

@@ -0,0 +1,87 @@
+discovery.docker "docker" {
+	host = "unix:///var/run/docker.sock"
+}
+
+loki.process "docker" {
+	forward_to = [loki.write.default.receiver]
+
+	stage.docker { }
+}
+
+discovery.relabel "docker" {
+	targets = discovery.docker.docker.targets
+
+	rule {
+		source_labels = ["__meta_docker_container_label_promtail_monitored"]
+		regex         = "true"
+		action        = "keep"
+	}
+
+	rule {
+		source_labels = ["__meta_docker_container_name"]
+		regex         = "/(.*)"
+		target_label  = "container"
+	}
+
+	rule {
+		source_labels = ["container"]
+		regex         = ".*charon.*"
+		target_label  = "job"
+		replacement   = "charon"
+	}
+
+	rule {
+		source_labels = ["container"]
+		regex         = ".*nethermind.*"
+		target_label  = "job"
+		replacement   = "nethermind"
+	}
+
+	rule {
+		source_labels = ["container"]
+		regex         = ".*lodestar.*"
+		target_label  = "job"
+		replacement   = "lodestar"
+	}
+
+	rule {
+		source_labels = ["container"]
+		regex         = ".*lighthouse.*"
+		target_label  = "job"
+		replacement   = "lighthouse"
+	}
+
+	rule {
+		source_labels = ["container"]
+		regex         = ".*mev-boost.*"
+		target_label  = "job"
+		replacement   = "mev-boost"
+	}
+
+	rule {
+		target_label = "cluster_name"
+		replacement  = "$CLUSTER_NAME"
+	}
+
+	rule {
+		target_label = "cluster_peer"
+		replacement  = "$CLUSTER_PEER"
+	}
+}
+
+loki.source.docker "docker" {
+	host          = "unix:///var/run/docker.sock"
+	targets       = discovery.docker.docker.targets
+	forward_to    = [loki.process.docker.receiver]
+	relabel_rules = discovery.relabel.docker.rules
+}
+
+loki.write "default" {
+	endpoint {
+		url = "$CHARON_LOKI_ADDRESSES"
+	}
+	external_labels = {
+		cluster_name = "$CLUSTER_NAME",
+		cluster_peer = "$CLUSTER_PEER",
+	}
+}

alloy/run.sh

@@ -0,0 +1,34 @@
+#!/bin/sh
+
+if [ -z "${CHARON_LOKI_ADDRESSES:-}" ]; then
+  echo "Error: \$CHARON_LOKI_ADDRESSES variable is empty" >&2
+  exit 1
+fi
+
+if [ -z "${CLUSTER_NAME:-}" ]; then
+  echo "Error: \$CLUSTER_NAME variable is empty" >&2
+  exit 1
+fi
+
+if [ -z "${CLUSTER_PEER:-}" ]; then
+  echo "Error: \$CLUSTER_PEER variable is empty" >&2
+  exit 1
+fi
+
+SRC="/etc/alloy/config.alloy.example"
+DST="/etc/alloy/config.alloy"
+
+echo "Rendering template: $SRC -> $DST"
+
+sed -e "s|\$CHARON_LOKI_ADDRESSES|${CHARON_LOKI_ADDRESSES}|g" \
+    -e "s|\$CLUSTER_NAME|${CLUSTER_NAME}|g" \
+    -e "s|\$CLUSTER_PEER|${CLUSTER_PEER}|g" \
+    "$SRC" > "$DST"
+
+echo "Config successfully rendered to $DST"
+
+# Execute the command passed as arguments if any
+if [ $# -gt 0 ]; then
+  echo "Executing: $@"
+  exec "$@"
+fi

logging.yml

@@ -1,17 +1,16 @@
 services:
-
-  promtail:
-    image: grafana/promtail:${PROMTAIL_VERSION:-2.8.2}
+  alloy:
+    image: grafana/alloy:${ALLOY_VERSION:-v1.11.3}
     environment:
       CHARON_LOKI_ADDRESSES: ${CHARON_LOKI_ADDRESSES}
       CLUSTER_NAME: ${CLUSTER_NAME}
       CLUSTER_PEER: ${CLUSTER_PEER}
-    command: -config.file=/etc/promtail/config.yml
     volumes:
-      - ./promtail:/etc/promtail
+      - ./alloy:/etc/alloy
       - /var/run/docker.sock:/var/run/docker.sock
     networks: [dvnode]
-    entrypoint: /etc/promtail/run.sh
+    entrypoint: /etc/alloy/run.sh
+    command: ["/bin/alloy", "run", "/etc/alloy/config.alloy", "--storage.path=/var/lib/alloy/data"]
     restart: unless-stopped
 
 networks: