Dell-Omnia-Clusters-HPC-AI/docs/Troubleshooting/FAQ.md

Frequently Asked Questions

What to do when hosts do not show on the AWX UI?

Resolution:

• Verify if the provisioned_hosts.yml file is present in the omnia/control_plane/roles/collect_node_info/files/ folder.
• Verify whether the hosts are listed in the provisioned_hosts.yml file.
• If hosts are not listed, then servers are not PXE booted yet. If hosts are listed, then an IP address has been assigned to them by DHCP. However, hosts are not displayed on the AWX UI as the PXE boot is still in process or is not initiated.
• Check for the reachable and unreachable hosts using the provision_report.yml tool present in the omnia/control_plane/tools folder. To run provision_report.yml, in the omnia/control_plane/ directory, run playbook -i roles/collect_node_info/files/provisioned_hosts.yml tools/provision_report.yml.

Why do Kubernetes Pods show ImagePullBack or ErrPullImage errors in their status?

Potential Cause:

* The errors occur when the Docker pull limit is exceeded.

Resolution:

* For `omnia.yml` and `control_plane.yml` : Provide the docker username and password for the Docker Hub account in the *omnia_config.yml* file and execute the playbook.
* For HPC cluster, during `omnia.yml execution`, a kubernetes secret 'dockerregcred' will be created in default namespace and patched to service account. User needs to patch this secret in their respective namespace while deploying custom applications and use the secret as imagePullSecrets in yaml file to avoid ErrImagePull. [Click here for more info](https://kubernetes.io/docs/tasks/configure-pod-container/pull-image-private-registry/)

Note: If the playbook is already executed and the pods are in ImagePullBack state, then run kubeadm reset -f in all the nodes before re-executing the playbook with the docker credentials.

What to do after a reboot if kubectl commands return: The connection to the server head_node_ip:port was refused - did you specify the right host or port?

On the control plane or the manager node, run the following commands:

* `swapoff -a`
* `systemctl restart kubelet`

How to clear up the configuration if control_plane.yml fails at the webui_awx stage?

In the webui_awx/files directory, delete the .tower_cli.cfg and .tower_vault_key files, and then re-run control_plane.yml.

Why would FreeIPA server/client installation fail?

Potential Cause:

The hostnames of the manager and login nodes are not set in the correct format.  

Resolution:

If you have enabled the option to install the login node in the cluster, set the hostnames of the nodes in the format: *hostname.domainname*. For example, *manager.omnia.test* is a valid hostname for the login node. **Note**: To find the cause for the failure of the FreeIPA server and client installation, see *ipaserver-install.log* in the manager node or */var/log/ipaclient-install.log* in the login node.

Why are inventory details not updated in AWX?

Potential Cause:

The provided device credentials may be invalid.

Resolution:

Manually validate/update the relevant login information on the AWX settings screen and re-run `device_inventory_job`. Optionally, wait 24 hours for the scheduled inventory job to run.

Why is the host list empty when executing control_plane.yml?

Hosts that are not in DHCP mode do not get populated in the host list when control_plane.yml is run.

Why does the task 'Install Packages' fails on the NFS node with the message: Failure in talking to yum: Cannot find a valid baseurl for repo: base/7/x86_64.

Potential Cause:

There are connections missing on the NFS node.  

Resolution:

    Ensure that there are 3 nics being used on the NFS node:
            1. For provisioning the OS
            2. For connecting to the internet (Management purposes)
            3. For connecting to PowerVault (Data Connection)

What to do if AWX jobs fail with Error creating pod: container failed to start, ImagePullBackOff?

Potential Cause:
After running control_plane.yml, the AWX image got deleted.
Resolution:

Run the following commands:<br>
1. `cd omnia/control_plane/roles/webui_awx/files`
2. `buildah bud -t custom-awx-ee awx_ee.yml`

Why does the task 'control_plane_common: Setting Metric' fail?

Potential Cause:

The device name and connection name listed by the network manager in `/etc/sysconfig/network-scripts/ifcfg-<nic name>` do not match.

Resolution:

1. Use nmcli connection to list all available connections and their attributes.
   Expected Output:
   
2. For any connections that have mismatched names and device names, edit the file /etc/sysconfig/network-scripts/ifcfg-<nic name> using vi editor.

Are hosts automatically cleaned up from the AWX UI when re-deploying the cluster?

No. Before re-deploying the cluster, users have to manually delete all hosts from the awx UI.

Why is the error "Wait for AWX UI to be up" displayed when control_plane.yml fails?

Potential Causes:

1. AWX is not accessible even after five minutes of wait time.
2. isMigrating or isInstalling is seen in the failure message.
   

Resolution:
Wait for AWX UI to be accessible at http://<management-station-IP>:8081, and then run the control_plane.yml file again, where management-station-IP is the IP address of the management node.

Why does Omnia Control Plane fail at Task: control_plane_common: Assert Value of idrac_support if mngmt_network container needed?

When device_config_support is set to true, idrac_support also needs to be set to true.

What to do if the nodes in a Kubernetes cluster reboot:

Wait for 15 minutes after the Kubernetes cluster reboots. Next, verify the status of the cluster using the following commands:

• kubectl get nodes on the manager node to get the real-time k8s cluster status.
  
• kubectl get pods --all-namespaces on the manager node to check which the pods are in the Running state.
• kubectl cluster-info on the manager node to verify that both the k8s master and kubeDNS are in the Running state.

What to do when the Kubernetes services are not in the Running state:

1. Run kubectl get pods --all-namespaces to verify that all pods are in the Running state.
2. If the pods are not in the Running state, delete the pods using the command:kubectl delete pods <name of pod>
3. Run the corresponding playbook that was used to install Kubernetes: omnia.yml, jupyterhub.yml, or kubeflow.yml.

What to do when the JupyterHub or Prometheus UI is not accessible:

Run the command kubectl get pods --namespace default to ensure nfs-client pod and all Prometheus server pods are in the Running state.

While configuring Cobbler, why does the control_plane.yml fail during the Run import command?

Cause:

• The mounted .iso file is corrupt.
  

Resolution:

1. Go to var->log->cobbler->cobbler.log to view the error.
2. If the error message is repo verification failed, the .iso file is not mounted properly.
3. Verify that the downloaded .iso file is valid and correct.
4. Delete the Cobbler container using docker rm -f cobbler and rerun control_plane.yml.

How to enable DHCP routing on Compute Nodes:

To enable routing, update the primary_dns and secondary_dns in base_vars with the appropriate IPs (hostnames are currently not supported). For compute nodes that are not directly connected to the internet (ie only host network is configured), this configuration allows for internet connectivity.

Why does PXE boot fail with tftp timeout or service timeout errors?

Potential Causes:

• RAID is configured on the server.
• Two or more servers in the same network have Cobbler services running.
  
• The target compute node does not have a configured PXE device with an active NIC.

Resolution:

1. Create a Non-RAID or virtual disk on the server.
   
2. Check if other systems except for the management node have cobblerd running. If yes, then stop the Cobbler container using the following commands: docker rm -f cobbler and docker image rm -f cobbler.
3. On the server, go to BIOS Setup -> Network Settings -> PXE Device. For each listed device (typically 4), configure an active NIC under PXE device settings

What to do when Slurm services do not start automatically after the cluster reboots:

• Manually restart the slurmd services on the manager node by running the following commands: systemctl restart slurmdbd systemctl restart slurmctld systemctl restart prometheus-slurm-exporter
• Run systemctl status slurmd to manually restart the following service on all the compute nodes.

Why do Slurm services fail?

Potential Cause: The slurm.conf is not configured properly.

Recommended Actions:

1. Run the following commands: slurmdbd -Dvvv slurmctld -Dvvv
2. Refer the /var/lib/log/slurmctld.log file for more information.

What causes the "Ports are Unavailable" error?

Cause: Slurm database connection fails.

Recommended Actions:

1. Run the following commands: slurmdbd -Dvvv slurmctld -Dvvv
2. Refer the /var/lib/log/slurmctld.log file.
3. Check the output of netstat -antp | grep LISTEN for PIDs in the listening state.
4. If PIDs are in the Listening state, kill the processes of that specific port.
5. Restart all Slurm services:

slurmctl restart slurmctld on manager node

systemctl restart slurmdbd on manager node

systemctl restart slurmd on compute node

Why do Kubernetes Pods stop communicating with the servers when the DNS servers are not responding?

Potential Cause: The host network is faulty causing DNS to be unresponsive

Resolution:

1. In your Kubernetes cluster, run kubeadm reset -f on all the nodes.
2. On the management node, edit the omnia_config.yml file to change the Kubernetes Pod Network CIDR. The suggested IP range is 192.168.0.0/16. Ensure that the IP provided is not in use on your host network.
3. Execute omnia.yml and skip slurm ansible-playbook omnia.yml --skip-tags slurm

Why does pulling images to create the Kubeflow timeout causing the 'Apply Kubeflow Configuration' task to fail?

Potential Cause: Unstable or slow Internet connectivity.
Resolution:

1. Complete the PXE booting/format the OS on the manager and compute nodes.
2. In the omnia_config.yml file, change the k8s_cni variable value from calico to flannel.
3. Run the Kubernetes and Kubeflow playbooks.
   

What to do if jobs hang in 'pending' state on the AWX UI:

Run kubectl rollout restart deployment awx -n awx from the control plane and try to re-run the job.

If the above solution doesn't work,

1. Delete all the inventories, groups and organization from AWX UI.
2. Delete the folder: /var/nfs_awx.
3. Delete the file: omnia/control_plane/roles/webui_awx/files/.tower_cli.cfg.
4. Re-run control_plane.yml.
   

What to do after a control plane reboot?

1. Once the control plane reboots, wait for 10-15 minutes to allow all k8s pods and services to come up. This can be verified using:
2. kubectl get pods --all-namespaces
3. If the pods do not come up, check /var/log/omnia.log for more information.
4. Cobbler profiles are not persistent across reboots. The latest profile will be available post-reboot based on the values of provision_os and iso_file_path in base_vars.yml. Re-run control_plane.yml with different values for provision_os and iso_file_path to restore the profiles.
5. Devices that have had their IP assigned dynamically via DHCP may get assigned new IPs. This in turn can cause duplicate entries for the same device on AWX. Clusters may also show inconsistency and ambiguity.

How to clear existing DHCP leases after a management NIC IP change?

If device_config_support is set to TRUE,

1. Reboot the ethernet TOR (Top of the Rack) switches in your environment.
2. If the leases aren't cleared, reboot the devices that have not registered the new IP. If device_config_support is set to FALSE, no reboots are required.

Why is permission denied when executing the idrac.yml file or other .yml files from AWX?

Potential Cause: The "PermissionError: [Errno 13] Permission denied" error is displayed if you have used the ansible-vault decrypt or encrypt commands.
Resolution:

• Update permissions on the relevant .yml using chmod 664 <filename>.yml

It is recommended that the ansible-vault view or edit commands are used and not the ansible-vault decrypt or encrypt commands.

What to do if the LC is not ready:

• Verify that the LC is in a ready state for all servers: racadm getremoteservicesstatus
• Launch iDRAC template.

What to do if the network CIDR entry of iDRAC IP in /etc/exports file is missing:

• Add an additional network CIDR range of iDRAC IPs in the /etc/exports file if the iDRAC IP is not in the management network range provided in base_vars.yml.

What to do if a custom ISO file is not present on the device:

• Re-run the control_plane.yml file.

What to do if the management_station_ip.txt file under provision_idrac/files folder is missing:

• Re-run the control_plane.yml file.

Is Disabling 2FA supported by Omnia?

• Disabling 2FA is not supported by Omnia and must be manually disabled.

The provisioning of PowerEdge servers failed. How do I clean up before starting over?

1. Delete the respective iDRAC IP addresses from the provisioned_idrac_inventory on the AWX UI or delete the provisioned_idrac_inventory to delete the iDRAC IP addresses of all the servers in the cluster.
2. Launch the iDRAC template from the AWX UI.

What to do if PowerVault throws the error: Error: The specified disk is not available. - Unavailable disk (0.x) in disk range '0.x-x':

1. Verify that the disk in question is not part of any pool: show disks
2. If the disk is part of a pool, remove it and try again.

Why does PowerVault throw the error: You cannot create a linear disk group when a virtual disk group exists on the system.?

At any given time only one type of disk group can be created on the system. That is, all disk groups on the system have to exclusively be linear or virtual. To fix the issue, either delete the existing disk group or change the type of pool you are creating.

Is provisioning server using BOSS controller supported by Omnia?

• Provisioning server using BOSS controller is not supported by Omnia. It will be supported in upcoming releases.

What to do when iDRAC template execution throws a warning regarding older firmware versions:

Potential Cause: Older firmware version in PowerEdge servers. Omnia supports only iDRAC 8 based Dell EMC PowerEdge Servers with firmware versions 2.75.75.75 and above and iDRAC 9 based Dell EMC PowerEdge Servers with Firmware versions 4.40.40.00 and above.

1. Update iDRAC firmware version in PowerEdge servers manually to the supported version.
2. Re-run idrac_template.

What steps have to be taken to re-run control_plane.yml after a Kubernetes reset?

1. Delete the folder: /var/nfs_awx
2. Delete the file: /<project name>/control_plane/roles/webui_awx/files/.tower_cli.cfg

Once complete, it's safe to re-run control_plane.yml.

Why does the Initialize Kubeadm task fail with 'nnode.Registration.name: Invalid value: \"\"'?

Potential Cause: The control_plane playbook does not support hostnames with an underscore in it such as 'mgmt_station'.

As defined in RFC 822, the only legal characters are the following:

1. Alphanumeric (a-z and 0-9): Both uppercase and lowercase letters are acceptable, and the hostname is case insensitive. In other words, dvader.empire.gov is identical to DVADER.EMPIRE.GOV and Dvader.Empire.Gov.

2. Hyphen (-): Neither the first nor the last character in a hostname field should be a hyphen.

3. Period (.): The period should be used only to delimit fields in a hostname (e.g., dvader.empire.gov)

What to do when JupyterHub pods are in 'ImagePullBackOff' or 'ErrImagePull' status after executing jupyterhub.yml:

Potential Cause: Your Docker pull limit has been exceeded. For more information, click here

1. Delete Jupyterhub deployment by executing the following command in manager node: helm delete jupyterhub -n jupyterhub
2. Re-execute jupyterhub.yml after 8-9 hours.

What to do when Kubeflow pods are in 'ImagePullBackOff' or 'ErrImagePull' status after executing kubeflow.yml:

Potential Cause: Your Docker pull limit has been exceeded. For more information, click here

1. Delete Kubeflow deployment by executing the following command in manager node: kfctl delete -V -f /root/k8s/omnia-kubeflow/kfctl_k8s_istio.v1.0.2.yaml
2. Re-execute kubeflow.yml after 8-9 hours

Can Cobbler deploy both Rocky and CentOS at the same time?

No. During Cobbler based deployment, only one OS is supported at a time. If the user would like to deploy both, please deploy one first, unmount /mnt/iso and then re-run cobbler for the second OS.

Why do Firmware Updates fail for some components with Omnia?

Due to the latest catalog.xml file, Firmware updates may fail for certain components. Omnia execution doesn't get interrupted but an error gets logged on AWX. For now, please download those individual updates manually.

Why does the Task [network_ib : Authentication failure response] fail with the message 'Status code was -1 and not [302]: Request failed: ' on Infiniband Switches when running infiniband.yml?

To configure a new Infiniband Switch, it is required that HTTP and JSON gateway be enabled. To verify that they are enabled, run:

show web (To check if HTTP is enabled)

show json-gw (To check if JSON Gateway is enabled)

To correct the issue, run:

web http enable (To enable the HTTP gateway)

json-gw enable (To enable the JSON gateway)