Nagios: Add init container for generating hosts

This updates the Nagios chart to include an init container for
generating the host and host group definitions Nagios requires to
function. The benefit is that Nagios does not need to constantly
attempt to update its host and host group definitions, which
currently triggers a restart of the Nagios service even in cases
where the host file hasn't changed.  With the introduction of an
init container for handling this, we can also remove the service
check definition and command definition for executing the plugin
at periodic intervals

Depends-On: https://review.opendev.org/668197

Change-Id: Id1d63d8c99850b960eb352361d7796162bd6be2f
Signed-off-by: Steve Wilkerson <sw5822@att.com>

nagios/templates/deployment.yaml

@@ -96,6 +96,18 @@ spec:
       {{- end }}
       initContainers:
 {{ tuple $envAll "nagios" list | include "helm-toolkit.snippets.kubernetes_entrypoint_init_container" | indent 8 }}
+        - name: define-nagios-hosts
+{{ tuple $envAll "nagios" | include "helm-toolkit.snippets.image" | indent 10 }}
+{{ tuple $envAll $envAll.Values.pod.resources.nagios | include "helm-toolkit.snippets.kubernetes_resources" | indent 10 }}
+          command:
+            - /usr/lib/nagios/plugins/define-nagios-hosts.py
+            - --object_file_loc
+            - /opt/nagios/etc/conf.d/nagios-hosts.cfg
+          volumeMounts:
+            - name: pod-tmp
+              mountPath: /tmp
+            - name: nagios-confd
+              mountPath: /opt/nagios/etc/conf.d
       containers:
         - name: apache-proxy
 {{ tuple $envAll "apache_proxy" | include "helm-toolkit.snippets.image" | indent 10 }}
@@ -181,6 +193,8 @@ spec:
           volumeMounts:
             - name: pod-tmp
               mountPath: /tmp
+            - name: nagios-confd
+              mountPath: /opt/nagios/etc/conf.d
             - name: nagios-etc
               mountPath: /opt/nagios/etc/nagios.cfg
               subPath: nagios.cfg
@@ -210,6 +224,8 @@ spec:
           emptyDir: {}
         - name: pod-var-log
           emptyDir: {}
+        - name: nagios-confd
+          emptyDir: {}
         - name: nagios-etc
           secret:
             secretName: nagios-etc

nagios/values.yaml

@@ -586,11 +586,6 @@ conf:
           command_name check_ceph_health
         }
 
-        define command {
-          command_line $USER1$/define-nagios-hosts.py --object_file_loc /opt/nagios/etc/objects/prometheus_discovery_objects.cfg
-          command_name check_prometheus_hosts
-        }
-
         define command {
           command_line $USER1$/query_elasticsearch.py $USER9$ '$ARG1$' '$ARG2$' '$ARG3$' '$ARG4$' '$ARG5$' --simple_query '$ARG6$' --simple_query_fields '$ARG7$' --match '$ARG8$' --range '$ARG9$'
           command_name check_es_query
@@ -1178,14 +1173,6 @@ conf:
           use generic-service
         }
 
-        define service {
-          check_command check_prometheus_hosts
-          check_interval 900
-          hostgroup_name prometheus-hosts
-          service_description Prometheus_hosts-update
-          use notifying_service
-        }
-
         define service {
           check_command check_prom_alert!pg_replication_fallen_behind!CRITICAL- Postgres Replication lag is over 2 minutes!OK- postgresql replication lag is nominal.
           hostgroup_name prometheus-hosts
@@ -1428,7 +1415,7 @@ conf:
         cfg_file=/opt/nagios/etc/objects/contacts.cfg
         cfg_file=/opt/nagios/etc/objects/timeperiods.cfg
         cfg_file=/opt/nagios/etc/objects/templates.cfg
-        cfg_file=/opt/nagios/etc/objects/prometheus_discovery_objects.cfg
+        cfg_file=/opt/nagios/etc/conf.d/nagios-hosts.cfg
 
         check_external_commands=1
         check_for_orphaned_hosts=1