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5.4 - Troubleshooting Commands

Objectives

  • Describe how to use SSH to connect to a Tanzu Kubernetes VM
  • Detail the steps to troubleshoot a failed cluster deployment

Connecting to Cluster Nodes with SSH

  • SSH can be used connect to individual nodes in both management and Tanzu Kubernetes clusters
  • For this to happen, you need an SSH key pair - one should already exist following deployment of the management cluster
  • The SSH key entered in the installer for the management cluster is associated with the CAPV user account
  • ssh capv@<VM IP Address>
  • Assume root privileges with sudo -i
  • As the SSH key is present on the system running the SSH command, no password will eb required

Failure of Management Cluster Create Command

  • Sometimes a cluster fails to create - a typical error is waiting for cert-manager to be available
  • Following steps can be used:
  • Verify node status kubectl get nodes
  • Verify pod status kubectl get pods -A
  • For any failing pods, check the logs and events:
    • kubectl describe pod -n <namespace> <pod name>
    • kubectl logs -n <namespace> <pod name>
  • Resolve issues with configuration or connectivity based on output
  • Delete the management cluster - tanzu management-cluster delete
  • Run the create command again to ensure a clean deployment: tanzu management-cluster create

Recovering Cluster Credentials

  • Run tanzu management-cluster create - recreates the .kube-tkg/config file
  • Obtain the IP address of the management cluster control plane node from vSphere
  • Use SSH to login to the management cluster control plane node: ssh capv@<node IP address>
  • Access the admin.conf file in the management cluster - sudo cat /etc/kubernetes/admin.conf
  • Copy the following into the local .kube-tkg/config file:
  • Cluster name
  • Cluster user name
  • Cluster context
  • Client certificate data