How To Resolve the 'invalid memory address or nil pointer dereference' Runtime Error

Background

The RealTheory collector requires the Metrics Server to be installed on the Kubernetes cluster. The Metrics Server is automatically installed with some managed versions of Kubernetes. The following table indicates which managed Kubernetes offerings include the Metrics Server as part of the standard offering:

If the Metrics Server is not installed on a cluster where the RealTheory collector is installed, the collector will try to process the node metrics, but the data will not be available.

Solution

1. Check the RealTheory collector logs:

   1. Run the following command to identify the pod name:

      kubectl \-n real-theory-system get pods

   2. Run the following command to get the RealTheory collector logs:

      kubectl \-n real-theory-system logs \<pod-name\>

      where \<pod-name\> is the name of the pod identified in Step 1a.

2. Review the logs for a message that is similar to the following:

   INFORMATION: 2025/02/26 22:22:58.673855 monitor.go:85: k8s monitor has started  
   panic: runtime error: invalid memory address or nil pointer dereference  
   \[signal SIGSEGV: segmentation violation code=0x1 addr=0x60 pc=0x12b9ac1\]  
   goroutine 83 \[running\]:  
   [realtheory.io/k8s/collector/models/node.ConvertNodeMetrices({0x1908f00](http://realtheory.io/k8s/collector/models/node.ConvertNodeMetrices\(%7B0x1908f00)?, 0xc0000b6410?}, 0xc000176008, 0x0)  
   /theory/models/node/metrics.go:59 \+0x81  
   [realtheory.io/k8s/collector/monitor.(\*Monitor).getNodes(0xc0002ad040](http://realtheory.io/k8s/collector/monitor.\(*Monitor\).getNodes\(0xc0002ad040), {0x1908f00?, 0xc0000b6230?}, 0xc0003ff340)  
   /theory/monitor/monitor.go:814 \+0x1d7  
   [realtheory.io/k8s/collector/monitor.(\*Monitor).Start(0xc0002ad040](http://realtheory.io/k8s/collector/monitor.\(*Monitor\).Start\(0xc0002ad040), {0x1908f00, 0xc000424050})  
   /theory/monitor/monitor.go:110 \+0x1fb  
   created by main.main in goroutine 1  
   /theory/app.go:125 \+0x81e  
   

3. If the log contains this message, install the metrics server on the associated cluster.