Nagios: Ensure processes are reaped

This moves Nagios to run as child processes of either
the pause container or use the hosts init system (for k8s <1.10)
to prevent defunct process sprawl

Change-Id: I6a93d446577674b0b012f9567d5e6a5794ebc44b

nagios/templates/deployment.yaml

@@ -85,6 +85,11 @@ spec:
       nodeSelector:
         {{ .Values.labels.nagios.node_selector_key }}: {{ .Values.labels.nagios.node_selector_value | quote }}
       terminationGracePeriodSeconds: {{ .Values.pod.lifecycle.termination_grace_period.nagios.timeout | default "30" }}
+      {{- if or ( gt .Capabilities.KubeVersion.Major "1" ) ( ge .Capabilities.KubeVersion.Minor "10" ) }}
+      shareProcessNamespace: true
+      {{- else }}
+      hostPID: true
+      {{- end }}
       initContainers:
 {{ tuple $envAll "nagios" list | include "helm-toolkit.snippets.kubernetes_entrypoint_init_container" | indent 8 }}
         - name: nagios-log-ownership