Add log monitoring guidance and examples to "About subscription licenses" (#91)

* Add log monitoring examples and guidance to "About subscription licenses"

* added log warnings to include

Author: travisamartin

content/includes/licensing-and-reporting/log-location-and-monitoring.md

@@ -0,0 +1,33 @@
+---
+docs:
+---
+
+Monitor the [NGINX error log](https://nginx.org/en/docs/ngx_core_module.html#error_log), typically located at `/var/log/nginx/error.log`, for subscription-related issues — such as failed usage reports or approaching license expirations — to catch problems early and keep your subscription compliant.
+
+<br>
+
+Examples of subscription-related log entries include:
+
+- **Failure to upload usage reports**:
+
+  ``` text
+  [error] 36387#36387: server returned 500 for <fqdn>:<port> during usage report
+  [error] 36528#36528: <fqdn>:<port> could not be resolved (host not found) during usage report
+  [error] 36619#36619: connect() failed (111: Connection refused) for <fqdn>:<port> during usage report
+  [error] 38888#88: server returned 401 for <ip_address>:443 during usage report
+  ```
+
+- **License approaching expiration**:
+
+  ``` text
+  [warn] license will expire in 14 days
+  ```
+
+- **License expiration**:
+
+  ``` text
+  [alert] license expiry; grace period will end in 89 days
+  [emerg] license expired
+  ```
+
+  {{<important>}}When a license expires, NGINX Plus stops processing traffic.{{</important>}}

content/nim/admin-guide/license/report-usage-connected-deployment.md

@@ -80,3 +80,9 @@ If you prefer submitting usage reports to F5 manually, follow these steps:
 ## What's reported
 
 {{< include "licensing-and-reporting/reported-usage-data.md" >}}
+
+---
+
+## Error log location and monitoring {#log-monitoring}
+
+{{< include "licensing-and-reporting/log-location-and-monitoring.md" >}}

content/nim/disconnected/report-usage-disconnected-deployment.md

@@ -185,3 +185,9 @@ To upload the the usage acknowledgement:
 ## What’s reported {#telemetry}
 
 {{< include "licensing-and-reporting/reported-usage-data.md" >}}
+
+---
+
+## Error log location and monitoring {#log-monitoring}
+
+{{< include "licensing-and-reporting/log-location-and-monitoring.md" >}}

content/solutions/about-subscription-licenses.md

@@ -99,6 +99,12 @@ mgmt {
 
 ---
 
+## Error log location and monitoring {#log-monitoring}
+
+{{< include "licensing-and-reporting/log-location-and-monitoring.md" >}}
+
+---
+
 ## Understand reported usage metrics {#usage-metrics}
 
 {{< include "licensing-and-reporting/reported-usage-data.md" >}}