send service logs to local6 facility to save space

Otherwise all service logs go into `/var/log/syslog` which becomes huge.

The `local6` syslog facility is the one handled by our default rsyslog
configuration and sends logs to `/var/log/service` directories as well
as to Logstash service for aggregation in the ELK stack.

Depends on:
https://github.com/status-im/infra-role-bootstrap-linux/commit/9ad8bb7d

Signed-off-by: Jakub Sokołowski <jakub@status.im>

defaults/main.yml

@@ -5,6 +5,7 @@ beacon_node_path: '/data/{{ beacon_node_service_name }}'
 beacon_node_data_path: '{{ beacon_node_path }}/data'
 beacon_node_data_folder: 'shared_{{ beacon_node_network }}_0'
 beacon_node_repo_path: '{{ beacon_node_path }}/repo'
+beacon_node_logs_link: '{{ beacon_node_path }}/logs'
 beacon_node_netkey_path: '{{ beacon_node_data_path }}/netkey'
 beacon_node_rpc_script_path: '{{ beacon_node_path }}/rpc.sh'
 beacon_node_build_script_path: '{{ beacon_node_path }}/build.sh'

tasks/service.yml

@@ -1,4 +1,11 @@
 ---
+- name: Symlink service logs folder
+  file:
+    src: '/var/log/service/{{ beacon_node_service_name }}'
+    dest: '{{ beacon_node_logs_link }}'
+    state: 'link'
+    force: true
+
 - name: Create systemd Unit file
   template:
     src: 'beacon-node.service.j2'

templates/beacon-node.service.j2

@@ -8,6 +8,8 @@ After=network-online.target
 User={{ beacon_node_user }}
 Group={{ beacon_node_group }}
 WorkingDirectory={{ beacon_node_path }}
+SyslogIdentifier={{ beacon_node_service_name }}
+SyslogFacility=local6
 Restart=on-failure
 ExecStart={{ beacon_node_repo_path }}/build/nimbus_beacon_node \
     --network={{ beacon_node_network }} \