feat(roles/logstash): add optional variables for setting up stack monitoring with Elastic agent (#235)

Author: ebuerki-lf

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+* **role:logstash**: Add optional variables `logstash__monitoring_cluster_uuid`, `logstash__monitoring_enabled`.
 * **role:elasticsearch**: Add optional variables `elasticsearch__cluster_routing_allocation_disk_watermark_flood_stage_frozen_max_headroom`, `elasticsearch__cluster_routing_allocation_disk_watermark_flood_stage_max_headroom`, `elasticsearch__cluster_routing_allocation_disk_watermark_high_max_headroom`, `elasticsearch__cluster_routing_allocation_disk_watermark_low_max_headroom`.
 * **role:elasticsearch**: Add optional variable `elasticsearch__cluster_routing_allocation_disk_watermark_flood_stage_frozen`.
 * **role:graylog_datanode**: Add optional variable `graylog_datanode__raw`.

roles/logstash/README.md

@@ -84,6 +84,18 @@ If you use the [logstash playbook](https://github.com/Linuxfabrik/lfops/blob/mai
 * Type: String.
 * Default: `'info'`
 
+`logstash__monitoring_cluster_uuid`
+
+* Elasticsearch Cluster UUID. Binds the metrics of Logstash to this specific cluster.
+* Type: String.
+* Default: unset
+
+`logstash__monitoring_enabled`
+
+* Enables or disables default collection of Logstash monitoring data.
+* Type: Bool.
+* Default: `true`
+
 `logstash__node_name`
 
 * A descriptive name for the node.
@@ -218,6 +230,8 @@ logstash__grok_patterns__host_var:
     state: 'absent'
 logstash__java_opts: '-Djava.io.tmpdir={{ logstash__path_data }}/tmp'
 logstash__log_level: 'info'
+logstash__monitoring_cluster_uuid: 'zk-HjQtYQGyL3NFSSu7InA'
+logstash__monitoring_enabled: false
 logstash__node_name: '{{ ansible_facts["nodename"] }}'
 logstash__path_data: '/var/lib/logstash'
 logstash__path_logs: '/var/log/logstash'

roles/logstash/defaults/main.yml

@@ -14,6 +14,7 @@ logstash__java_opts: >
   -Xms{{ [((ansible_facts["memtotal_mb"] * 0.6) | int), 8192] | min }}m
   -Xmx{{ [((ansible_facts["memtotal_mb"] * 0.6) | int), 8192] | min }}m
 logstash__log_level: 'info'
+logstash__monitoring_enabled: true
 logstash__node_name: '{{ ansible_facts["nodename"] }}'
 logstash__path_data: '/var/lib/logstash'
 logstash__path_logs: '/var/log/logstash'

roles/logstash/tasks/main.yml

@@ -1,3 +1,15 @@
+- block:
+
+  - name: 'Ensure cluster uuid is valid'
+    ansible.builtin.assert:
+      that:
+        - 'logstash__monitoring_cluster_uuid is ansible.builtin.regex("^[A-Za-z0-9_-]{22}$")'
+      fail_msg: '`logstash__monitoring_cluster_uuid: {{ logstash__monitoring_cluster_uuid }}` is not a valid cluster uuid'
+    when: 'logstash__monitoring_cluster_uuid is defined and logstash__monitoring_cluster_uuid | length > 0'
+
+  tags:
+    - 'always'
+
 - block:
 
   - name: 'Install logstash'

roles/logstash/templates/etc/logstash/logstash.yml.j2

@@ -1,5 +1,5 @@
 # {{ ansible_managed }}
-# 2026012801
+# 2026042801
 
 # Settings file in YAML
 #
@@ -374,6 +374,13 @@ path.logs: '{{ logstash__path_logs }}'
 #xpack.geoip.downloader.enabled: true
 #xpack.geoip.downloader.endpoint: "https://geoip.elastic.co/v1/database"
 
+# Stack Monitoring
+# https://www.elastic.co/docs/reference/logstash/monitoring-with-elastic-agent
+monitoring.enabled: {{ logstash__monitoring_enabled | bool | string | lower }}
+{% if logstash__monitoring_cluster_uuid is defined and logstash__monitoring_cluster_uuid | length > 0 %}
+monitoring.cluster_uuid: '{{ logstash__monitoring_cluster_uuid }}'
+{% endif %}
+
 {% if logstash__raw | length %}
 # raw
 {{ logstash__raw }}