Update NodeClockNotSynchronising.md runbook

content/runbooks/node/NodeClockNotSynchronising.md

@@ -15,8 +15,69 @@ Time is not automatically synchronizing on the node. This can cause issues with
 
 ## Diagnosis
 
-TODO
+1. **Confirm the alert condition**
+
+   ```bash
+   timedatectl
+   ```
+
+   Look for:
+
+   * `System clock synchronized: no`
+   * `NTP service: inactive`
+
+2. **Check the time synchronisation service**
+   Most nodes use `chronyd`:
+
+   ```bash
+   systemctl status chronyd
+   ```
+
+   Common failure modes:
+
+   * Service is stopped or failed
+   * Service was OOM-killed
+   * No reachable NTP sources
+
 
 ## Mitigation
 
-See [Node Clok Skew Detected]({{< ref "./NodeClockSkewDetected.md" >}}) for mitigation steps.
+1. **Restart the time synchronisation service**
+   Restarting `chronyd` is safe on production nodes and does not restart workloads.
+
+   ```bash
+   sudo systemctl restart chronyd
+   ```
+
+2. **Verify the service is running**
+
+   ```bash
+   systemctl status chronyd
+   ```
+
+3. **Confirm clock synchronisation**
+
+   ```bash
+   timedatectl
+   ```
+
+   Expected:
+
+   * `System clock synchronized: yes`
+
+4. **If the service was OOM-killed**
+   Investigate memory pressure on the node:
+
+   ```bash
+   journalctl -k | grep -i oom
+   ```
+
+   Consider:
+
+   * Reviewing workload memory limits
+   * Adding a small amount of swap as a safety buffer
+   * Investigating recent deploys or memory spikes
+
+5. **If the issue persists**
+   Follow the mitigation steps in
+   [Node Clock Skew Detected](./NodeClockSkewDetected.md)