Certificate monitoring with Zabbix Agent 2
===== Overview =====
  - Details for each individual FQDN are stored in json files.
  - each json file contains the following information
==== json monitoring files ====
<code>
{
    "hostname": "example.com",
    "ip_address": "",
    "port": "443",
    "warning_days": "25",
    "critical_days": "10",
    "contact": "somebody to contact here",
    "ticket": "abc-1234"
  }
</code>
  - hostname: name of host to monitor
  - ip_address: if you need to check a specific ip address
  - port: tcp port to check
  - warning_days: number of days till expiration that a warning will alert will trigger
  - critical_days: number of days till expiration that a critical will alert will trigger
  - contact: contact information for this specific certificate
  - ticket: ticket number used to track the creation of the monitoring


*N.B.*
  - all fields are mandatory. 
  - the template doesn't currently handle missing fields cleanly.


===== setup =====
  - install jq to parse the json files , and Zabbix Agent 2
  - configure zabbix agent to allow 'system.run[]'
  - place json files in /certs/public/
  - add discover-certs.sh script to /zabbix/bin/ directory
    - should probably be done via external scripts directory
  - 

==== script ====
discover-certs.sh
<code bash>
#!/bin/sh
DIR="${1}"
if [ ! -d "${DIR}" ];then
        echo "${DIR} does not exist"
        exit 1
fi
jq -s '.' "${DIR}"/*.json
</code>





an item "get hosts to monitor" that will gather the json files ( tag: Application: Certificate Monitoring Discovery)

==== Discovery ====
For discovery:
  - Create a discovery rule as a dependent item of "get hosts to monitor"
  - preprocessing to create LLD macros
  {#CERT_EXPIRY_CRITICAL_DAYS} : $.critical_days
  {#CERT_EXPIRY_WARNING_DAYS} : $.warning_days
  {#CONTACT_INFO} : $.contact
  {#CRITICAL_DAYS} : $.critical_days
  {#HOSTNAME} : $.hostname
  {#IP_ADDRESS} : $.ip_address
  {#PORT} : $.port
  
=== Item prototypes ===
Item prototypes
Item prototype 1
  Name:  cert monitor for {#HOSTNAME}:{#PORT} {#IP_ADDRESS}

=== Trigger prototypes ===
Trigger prototypes