Extend troubleshooting doc

site/content/how-to/monitoring/troubleshooting.md

@@ -9,6 +9,80 @@ docs: "DOCS-1419"
 
 This topic describes possible issues users might encounter when using NGINX Gateway Fabric. When possible, suggested workarounds are provided.
 
+### General troubleshooting
+
+When investigating a problem or requesting help, there are important data points that can be collected to help understand what issues may exist.
+
+##### Resource status
+
+To check the status of a resource, use `kubectl describe`. This example checks the status of the `coffee` HTTPRoute, which has an error:
+
+```shell
+kubectl describe httproutes.gateway.networking.k8s.io coffee [-n namespace]
+```
+
+```text
+...
+Status:
+  Parents:
+    Conditions:
+      Last Transition Time:  2024-05-31T17:20:51Z
+      Message:               The route is accepted
+      Observed Generation:   4
+      Reason:                Accepted
+      Status:                True
+      Type:                  Accepted
+      Last Transition Time:  2024-05-31T17:20:51Z
+      Message:               spec.rules[0].backendRefs[0].name: Not found: "bad-backend"
+      Observed Generation:   4
+      Reason:                BackendNotFound
+      Status:                False
+      Type:                  ResolvedRefs
+    Controller Name:         gateway.nginx.org/nginx-gateway-controller
+    Parent Ref:
+      Group:         gateway.networking.k8s.io
+      Kind:          Gateway
+      Name:          gateway
+      Namespace:     default
+      Section Name:  http
+```
+
+If a resource has errors relating to its configuration or relationship to other resources, they can likely be read in the status. The `ObservedGeneration` in the status should match the `ObservedGeneration` of the resource. Otherwise, this could mean that the resource hasn't been processed yet or that the status failed to update.
+
+##### Events
+
+Events created by NGINX Gateway Fabric or other Kubernetes components could indicate system or configuration issues. To see events:
+
+```shell
+kubectl get events [-n namespace]
+```
+
+For example, a warning event when the NginxGateway configuration CRD is deleted:
+
+```text
+kubectl -n nginx-gateway get event
+LAST SEEN   TYPE      REASON              OBJECT                                           MESSAGE
+5s          Warning   ResourceDeleted     nginxgateway/ngf-config                          NginxGateway configuration was deleted; using defaults
+```
+
+##### Logs
+
+Logs from the NGINX Gateway Fabric control plane and data plane can contain information that isn't available to status or events. These can include errors in processing or passing traffic.
+
+To see logs for the control plane container:
+
+```shell
+kubectl -n nginx-gateway logs <ngf-pod-name> -c nginx-gateway
+```
+
+To see logs for the data plane container:
+
+```shell
+kubectl -n nginx-gateway logs <ngf-pod-name> -c nginx
+```
+
+You can see logs for a crashed or killed container by adding the `-p` flag to the above commands.
+
 ### NGINX fails to reload
 
 #### Description