Building Clusters

  1. In the input/omnia_config.yml file, provide the required details.

Note

Without the login node, Slurm jobs can be scheduled only through the manager node.

  1. Create an inventory file in the omnia folder. Add login node IP address under the manager node IP address under the [manager] group, compute node IP addresses under the [compute] group, and Login node IP under the [login_node] group,. Check out the sample inventory for more information.

Note

  • Omnia checks for red hat subscription being enabled on RedHat nodes as a pre-requisite. Not having Red Hat subscription enabled on the manager node will cause omnia.yml to fail. If compute nodes do not have Red Hat subscription enabled, omnia.yml will skip the node entirely.

  • Omnia creates a log file which is available at: /var/log/omnia.log.

  • If only Slurm is being installed on the cluster, docker credentials are not required.

  1. To run omnia.yml:

ansible-playbook omnia.yml -i inventory

Note

To visualize the cluster (Slurm/Kubernetes) metrics on Grafana (On the control plane) during the run of omnia.yml, add the parameters grafana_username and grafana_password (That is ansible-playbook omnia.yml -i inventory -e grafana_username="" -e grafana_password=""). Alternatively, Grafana is not installed by omnia.yml if it’s not available on the Control Plane.

Using Skip Tags

Using skip tags, the scheduler running on the cluster can be set to Slurm or Kubernetes while running the omnia.yml playbook. This choice can be made depending on the expected HPC/AI workloads.

  • Kubernetes: ansible-playbook omnia.yml -i inventory --skip-tags "kubernetes" (To set Slurm as the scheduler)

  • Slurm: ansible-playbook omnia.yml -i inventory --skip-tags "slurm" (To set Kubernetes as the scheduler)

Note

  • If you want to view or edit the omnia_config.yml file, run the following command:

    • ansible-vault view omnia_config.yml --vault-password-file .omnia_vault_key – To view the file.

    • ansible-vault edit omnia_config.yml --vault-password-file .omnia_vault_key – To edit the file.

  • It is suggested that you use the ansible-vault view or edit commands and that you do not use the ansible-vault decrypt or encrypt commands. If you have used the ansible-vault decrypt or encrypt commands, provide 644 permission to omnia_config.yml.

Kubernetes Roles

As part of setting up Kubernetes roles, omnia.yml handles the following tasks on the manager and compute nodes:

  • Docker is installed.

  • Kubernetes is installed.

  • Helm package manager is installed.

  • All required services are started (Such as kubelet).

  • Different operators are configured via Helm.

  • Prometheus is installed.

Slurm Roles

As part of setting up Slurm roles, omnia.yml handles the following tasks on the manager and compute nodes:

  • Slurm is installed.

  • All required services are started (Such as slurmd, slurmctld, slurmdbd).

  • Prometheus is installed to visualize slurm metrics.

  • Lua and Lmod are installed as slurm modules.

  • Slurm restd is set up.

Login node

If a login node is available and mentioned in the inventory file, the following tasks are executed:

  • Slurmd is installed.

  • All required configurations are made to slurm.conf file to enable a slurm login node.

  • FreeIPA (the default authentication system on the login node) is installed to provide centralized authentication

Hostname requirements

  • In the examples folder, a mapping_host_file.csv template is provided which can be used for DHCP configuration. The header in the template file must not be deleted before saving the file. It is recommended to provide this optional file as it allows IP assignments provided by Omnia to be persistent across control plane reboots.

  • The Hostname should not contain the following characters: , (comma), . (period) or _ (underscore). However, the domain name is allowed commas and periods.

  • The Hostname cannot start or end with a hyphen (-).

  • No upper case characters are allowed in the hostname.

  • The hostname cannot start with a number.

  • The hostname and the domain name (that is: hostname00000x.domain.xxx) cumulatively cannot exceed 64 characters. For example, if the node_name provided in input/provision_config.yml is ‘node’, and the domain_name provided is ‘omnia.test’, Omnia will set the hostname of a target compute node to ‘node00001.omnia.test’. Omnia appends 6 digits to the hostname to individually name each target node.

Note

  • To enable the login node, ensure that login_node_required in input/omnia_config.yml is set to true.

  • To enable security features on the login node, ensure that enable_secure_login_node in input/omnia_config.yml is set to true.

  • To customize the security features on the login node, fill out the parameters in input/omnia_security_config.yml.

Warning

No users/groups will be created by Omnia.

Slurm job based user access

To ensure security while running jobs on the cluster, users can be assigned permissions to access compute nodes only while their jobs are running. To enable the feature:

cd scheduler
ansible-playbook job_based_user_access.yml -i inventory

Note

  • The inventory queried in the above command is to be created by the user prior to running omnia.yml as scheduler.yml is invoked by omnia.yml

  • Only users added to the ‘slurm’ group can execute slurm jobs. To add users to the group, use the command: usermod -a -G slurm <username>.

Installing LDAP Client

Manager and compute nodes will have LDAP client installed and configured if ldap_required is set to true. The login node does not have LDAP client installed.

Warning

No users/groups will be created by Omnia.

FreeIPA installation on the NFS node

IPA services are used to provide account management and centralized authentication. To set up IPA services for the NFS node in the target cluster, run the following command from the utils/cluster folder on the control plane:

cd utils/cluster
ansible-playbook install_ipa_client.yml -i inventory -e kerberos_admin_password="" -e ipa_server_hostname="" -e domain_name="" -e ipa_server_ipadress=""

Input Parameter

Definition

Variable value

kerberos_admin_password

“admin” user password for the IPA server on RockyOS and RedHat.

The password can be found in the file input/omnia_config.yml .

ipa_server_hostname

The hostname of the IPA server

The hostname can be found on the manager node.

domain_name

Domain name

The domain name can be found in the file input/omnia_config.yml.

ipa_server_ipadress

The IP address of the IPA server

The IP address can be found on the IPA server on the manager node using the ip a command. This IP address should be accessible from the NFS node.

Use the format specified under NFS inventory in the Sample Files for inventory.