To determine whether a Slurm node is a master (control) node or a compute node, you can use several methods depending on your access level and the information available on the node. Here are the most common approaches:

1. Check Slurm Configuration Files

Slurm configuration files usually define the roles of nodes. You can inspect these files if you have access:

• slurm.conf: This file lists all nodes and their roles.
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  grep -E '^NodeName|^ControlMachine' /etc/slurm/slurm.conf

  • The ControlMachine line specifies the master node.
  • The NodeName lines list all nodes, often with additional attributes like State=UNKNOWN or State=IDLE for compute nodes.

2. Use Slurm Commands

If Slurm is running, you can use the following commands:

• sinfo: Lists all nodes and their states.

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  sinfo -N

  • The master node is typically marked as mixed or cloud if it also runs jobs, or it may not appear in the compute node list.

• scontrol show nodes: Shows detailed information about each node.

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  scontrol show nodes

  • Look for the NodeName and State fields. The master node may have a different state or additional flags.

• scontrol show config: Displays the Slurm configuration, including the master node.

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  scontrol show config | grep ControlMachine

3. Check Hostname

• The master node often has a distinct hostname (e.g., master, headnode, or similar).
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  hostname

  • Compare this with the output of scontrol show config | grep ControlMachine.

4. Check Running Processes

• The master node runs Slurm daemons like slurmctld (Slurm controller daemon).
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  ps aux | grep slurm

  • If you see slurmctld, you are on the master node.
  • Compute nodes run slurmd (Slurm node daemon).

5. Check Network Configuration

• Master nodes often have specific network configurations or are the only nodes with external network access.

6. Ask the Cluster Administrator

If you are unsure or lack permissions, the cluster administrator can confirm the role of the node.

Summary Table