Ansible playbook-based tools for deploying Slurm and Kubernetes clusters for High Performance Computing, Machine Learning, Deep Learning, and High-Performance Data Analytics

This project is maintained by dellhpc

Frequently Asked Questions

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


How do I find the version of Omnia being used?

If control_plane.yml has run, a version file is created here: /opt/omnia/omnia_version.

What are the mapping files required when configuring in a LOM setup?

| File name | Purpose | Associated Variable (base_vars.yml) | Format | Sample File Path | |————————-|——————————————————————————————————-|—————————————-|———————————-|——————————————————| | Host mapping | Mapping file listing all devices (barring iDRAC) and provisioned hosts for DHCP configurations | host_mapping_file_path | xx:yy:zz:aa:bb,server, | omnia/examples/host_mapping_file_os_provisioning.csv | | Management mapping file | Mapping file listing iDRACs for DHCP configurations | mgmt_mapping_file_path | xx:yy:zz:aa:bb, | omnia/examples/mapping_device_file.csv |

Why does the task ‘nfs_client: Mount NFS client’ fail with No route to host?

Potential Cause:

Why does the task ‘control plane security: Authenticate as admin’ fail?

Potential Cause:
The required services are not running on the control plane. Verify the service status using:
systemctl status sssd-kcm.socket
systemctl status sssd.service

Why does the task ‘Gather facts from all the nodes’ stuck when re-running omnia.yml?

Potential Cause: Corrupted entries in the /root/.ansible/cp/ folder. For more information on this issue, check this out!
Resolution: Clear the directory /root/.ansible/cp/ using the following commands:
cd /root/.ansible/cp/
rm -rf *
Alternatively, run the task manually:
cd omnia/tools ansible-playbook gather_facts_resolution.yml

Why does the task ‘nfs_client: Mount NFS client’ fail with Failed to mount NFS client. Make sure NFS Server is running on IP xx.xx.xx.xx?

Potential Cause:

Why does configure_device_cli fail when awx_web_support is set to true in base_vars.yml?

Potential Cause: CLI templates require that AWX is disabled when deployed.
Resolution: Set awx_web_support to false when deploying configure_device_cli.

What to do when omnia.yml fails with nfs-server.service might not be running on NFS Server. Please check or start services?

Potential Cause: nfs-server.service is not running on the target node.
Resolution: Use the following commands to bring up the service:
systemctl start nfs-server.service
systemctl enable nfs-server.service

Why are service tags missing in the node inventory?

Potential Cause: Temporary network glitches may cause a loss of information.
Resolution: Re-run the playbook collect_node_info.yml to repopulate the data. Use the command ansible-playbook collect_node_info.yml to run the playbook.

Why do Password-less SSH tasks fail while running collect_node_info.yml?

Potential Cause:


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

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

What to do if AWX auto aborts jobs (Omnia template typically) when executed on a cluster larger than 5 nodes?

Use CLI to execute Omnia by default by disabling AWX (set awx_web_support in base_vars.yml to false).

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 does the task ‘Control Plane Common: Fetch the available subnets and netmasks’ fail with no ipv4_secondaries present?

Potential Cause: If a shared LOM environment is in use, the management network/host network NIC may only have one IP assigned to it.
Resolution: Ensure that the NIC used for host and data connections has 2 IPs assigned to it.

Why does the task ‘Deploy Job Templates: Launch Device Inventory Job Template’ fail with Monitoring of Job- device_inventory_job aborted due to timeout happen?

Potential Cause:
This error is caused by design. There is a mismatch between the AWX version (20.0.0) and the AWX galaxy collection (19.4.0) version used by control plane. At the time of design (Omnia 1.2.1), these were the latest available versions of AWX/AWX galaxy collection. This will be fixed in later code releases.

Note: This failure does not stop the execution of other tasks. Check the AWX log to verify that the script has run successfully.

Why does provisioning RHEL 8.3 fail on some nodes with “dasbus.error.DBusError: ‘NoneType’ object has no attribute ‘set_property’”?

This error is known to Red Hat and is being addressed here. Red Hat has offered a user intervention here. Omnia recommends that in the event of this failure, any OS other than RHEL 8.3.

Why do AWX job templates fail when awx_web_support is false in base_vars.yml?

As a pre-requisite to running AWX job templates, AWX should be enabled by setting awx_web_support to true in base_vars.yml.

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

Why aren’t all IPs that are available in dhcp.leases and mgmt_provisioned_hosts.yml updated in the Device Inventory Job/ iDRAC inventory during control_plane.yml execution?

Potential Cause: Certain IPs may not update in AWX immediately because the device may be assigned an IP previously and the DHCP lease has not expired.
Resolution: Wait for the DHCP lease for the relevant device to expire or restart the switch/device to clear the lease.

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’ fail 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)

Why is the Infiniband NIC down after provisioning the server?

  1. For servers running Rocky, enable the Infiniband NIC manually, use ifup <InfiniBand NIC>.
  2. If your server is running LeapOS, ensure the following pre-requisites are met before manually bringing up the interface:
    1. The following repositories have to be installed:
    2. Run: zypper install -n rdma-core librdmacm1 libibmad5 libibumad3 infiniband-diags to install IB NIC drivers. (If the drivers do not install smoothly, reboot the server to apply the required changes)
    3. Run: service network status to verify that wicked.service is running.
    4. Verify that the ifcfg-< InfiniBand NIC > file is present in /etc/sysconfig/network.
    5. Once all the above pre-requisites are met, bring up the interface manually using ifup <InfiniBand NIC>.
      Alternatively, run omnia.yml to activate the NIC.

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 due to space considerations (use df -h to diagnose the issue.).
Delete unnecessary files from the partition`` and then run the following commands:
1. cd omnia/control_plane/roles/webui_awx/files 2. buildah bud -t custom-awx-ee awx_ee.yml

Why do pods and images appear to get deleted automatically?

Potential Cause:
Lack of space in the root partition (/) causes Linux to clear files automatically (Use df -h to diagnose the issue).

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.


  1. Use nmcli connection to list all available connections and their attributes.
    Expected Output:
    NMCLI 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.

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.

Why does the idrac.yml template hang during the import SCP file task on certain target nodes?

Potential Causes:

  1. The server hardware does not allow for auto rebooting
  2. Pending jobs may be running at the time of applying the SCP configuration.


  1. Login to the iDRAC console to check if the server is stuck in boot errors (F1 prompt message). If true, clear the hardware error or disable POST (PowerOn Self Test).
  2. Reset iDRAC to clear the job queue (If a job is pending).

Why is the iDRAC server not reachable after running idrac.yml for certain target nodes?

Potential Causes:

  1. The server hardware does not allow for auto rebooting
  2. PXE booting is hung on the node


  1. Login to the iDRAC console to check if the server is stuck in boot errors (F1 prompt message). If true, clear the hardware error or disable POST (PowerOn Self Test).
  2. Hard-reboot the server to bring up the server and verify that the boot process runs smoothly. (If it gets stuck again, disable PXE and try provisioning the server via iDRAC.)

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:

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?


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:

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

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


  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 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.

  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.

Why is my NFS mount not visible on the client?

Potential Cause: The directory being used by the client as a mount point is already in use by a different NFS export.
Resolution: Verify that the directory being used as a mount point is empty by using cd <client share path> | ls or mount | grep <client share path>. If empty, re-run the playbook.

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:
    • kubectl get pods --all-namespaces
  2. If the pods do not come up, check /var/log/omnia/startup_omnia/startup_omnia_yyyy-mm-dd-HHMMSS.log for more information.
  3. 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.
  4. 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.

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:

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

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

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

Is Disabling 2FA supported by Omnia?

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 servers using BOSS controller supported by Omnia?

Provisioning server using BOSS controller is now supported by Omnia 1.2.1.

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 and above and iDRAC 9 based Dell EMC PowerEdge Servers with Firmware versions 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 ‘ 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, 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.,

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: <urlopen error [Errno 111] Connection refused>’ 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)

Why does the BeeGFS-client service fail?

Potential Causes:

  1. SELINUX may be enabled. (use sestatus to diagnose the issue)
  2. Ports 8008, 8003, 8004, 8005 and 8006 may be closed. (use systemctl status beegfs-mgmtd, systemctl status beegfs-meta, systemctl status beegfs-storage to diagnose the issue)
  3. The BeeGFS set up may be incompatible with Red Hat.


  1. If SeLinux is enabled, update the file /etc/sysconfig/selinux and reboot the server.
  2. Open all ports required by BeeGFS: 8008, 8003, 8004, 8005 and 8006
  3. Check the support matrix for Red Hat or Rocky to verify your set-up.
  4. For further insight into the issue, check out /var/log/beegfs-client.log

How many active NICs are configured by idrac.yml?

Upto 4 active NICs can be configured by idrac.yml. Past the first 4 NICs, all NICs will be ignored.

Why are the PXE device settings not configured by Omnia on some servers?

While the NIC qualifies as active, it may not qualify as a PXE device NIC (It may be a mellanox NIC). In such a situation, Omnia assumes that PXE device settings are already configured and proceeds to attempt a PXE boot.
If this is not the case, manually configure a PXE device NIC and re-run idrac.yml to proceed.

What to do when control_plane.yml fail with ‘Error: kinit: Connection refused while getting default ccache’ while completing the control plane security role?

  1. Start the sssd-kcm.socket: systemcl start sssd-kcm.socket
  2. Re-run control_plane.yml

Why does installing FreeIPA fail on Red Hat servers?

Potential Causes: Required repositories may not be enabled by your red hat subscription.
Resolution: Enable all required repositories via your red hat subscription.

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 does FreeIPA installation fail on the control plane when the public NIC provided is static?

Potential Cause: The network config file for the public NIC on the control plane does not define any DNS entries.
Resolution: Ensure the fields DNS1 and DNS2 are updated appropriately in the file /etc/sysconfig/network-scripts/ifcfg-<NIC name>.