docs: Add debugging 101 runbook

runbooks/source/debugging-101.html.md.erb

@@ -0,0 +1,38 @@
+---
+title: Debugging 101
+weight: 9999
+last_reviewed_on: 2024-08-23
+review_in: 6 months
+---
+
+# <%= current_page.data.title %>
+
+Useful dashboards and searches for debugging issues on the cluster, starting from a high level node view down to pods.
+
+## Grafana Dashboards
+
+### Kubernetes / View / Nodes
+
+https://grafana.live.cloud-platform.service.justice.gov.uk/d/k8s_views_nodes/kubernetes-views-nodes?orgId=1&var-job=node-exporter&var-datasource=prometheus&var-resolution=30s&var-node=ip-172-20-56-77.eu-west-2.compute.internal&var-instance=172.20.56.77:9100&from=now-1h&to=now
+
+This dashboard is useful for inspecting a node and seeing if there are any pods with excessive resource usage. The dashboard can be filtered by node.
+
+### Kubernetes / Compute Resources / Node (Pods)
+
+https://grafana.live.cloud-platform.service.justice.gov.uk/d/200ac8fdbfbb74b39aff88118e4d1c2c/kubernetes-compute-resources-node-pods?orgId=1&var-datasource=P5DCFC7561CCDE821&var-cluster=&var-node=ip-172-20-101-196.eu-west-2.compute.internal&var-node=ip-172-20-56-77.eu-west-2.compute.internal&from=now-1h&to=now
+
+Similar to the first dashboard but focuses on the pods rather than the nodes.
+
+### Kubernetes / Views / Pods
+
+https://grafana.live.cloud-platform.service.justice.gov.uk/d/k8s_views_pods/kubernetes-views-pods?orgId=1&refresh=30s
+
+A detailed view of individual pods, can filter based on namespace and refreshes by default every 30 seconds.
+
+### Kubernetes Nginx Ingress Controller NextGen - DevOps Nirvana2
+
+https://grafana.live.cloud-platform.service.justice.gov.uk/d/k8s-nginx-ingress-prometheus-ng2/5178fc76-29af-51b9-83a8-cbab85db37a6?orgId=1&refresh=1m
+
+This dashboard shows statistics around our ingresses.
+
+> This dashboard is slow to load.