1. Distributed Training Jobs on Kubernetes Node Groups


    In a Kubernetes environment, distributed training jobs can be handled efficiently by leveraging node groups. A node group is a collection of worker machines, known as nodes, that run containerized applications. When you want to run distributed training jobs, you can create a dedicated node group within your Kubernetes cluster specifically optimized for that purpose. This setup can be beneficial when you have jobs that require different resource scheduling than the rest of the workloads running on the cluster.

    To accomplish this with Pulumi, we will follow these general steps:

    1. Create a Kubernetes cluster if one doesn't already exist.
    2. Define a dedicated node group for our distributed training jobs.
    3. Label the node group appropriately to differentiate it from other groups.
    4. Apply taints to the node group to ensure only specific pods (e.g., our training jobs) can schedule on these nodes.
    5. Scale the node group based on the resource demand of the training jobs.

    We will use the Pulumi EKS package to manage the cluster and node group because it provides higher-level constructs that simplify the process. The pulumi_eks module helps streamline creating and managing clusters and node groups.

    Below is a Pulumi program written in Python that sets up a Kubernetes cluster and a dedicated node group for distributed training jobs.

    import pulumi import pulumi_eks as eks # We start by initializing a new EKS cluster. cluster = eks.Cluster('my-cluster') # Create an EKS Node Group for distributed training jobs. # The nodes in this group are labeled with 'workload-type: training' to help with scheduling. # They are also tainted to prevent other workloads from being scheduled on them. training_node_group = eks.NodeGroup('training-node-group', cluster=cluster.core, # Associate the node group with the main EKS cluster instance_type='m5.large', # Choose an instance type suitable for your training workload desired_capacity=2, # Start with desired number of nodes in the node group min_size=1, # Minimum number of nodes in the node group max_size=5, # Maximum number of nodes in the node group labels={'workload-type': 'training'}, # Label for identifying nodes in this group taints={ # Taints to ensure only training jobs are scheduled on these nodes 'workload-type': eks.TaintEffect.NO_SCHEDULE } ) # Exporting the cluster kubeconfig so that we can interact with the cluster. pulumi.export('kubeconfig', cluster.kubeconfig)

    In this program:

    • eks.Cluster creates a new EKS cluster.
    • eks.NodeGroup creates a node group within the cluster with specific configurations for instance type, capacity, labels, and taints.
      • instance_type specifies the type of EC2 instances to use for nodes.
      • desired_capacity, min_size, and max_size control the scaling properties of the node group.
      • labels provide a way to tag the nodes so that Kubernetes can schedule workloads accordingly.
      • taints apply scheduling constraints to ensure that only pods that tolerate these taints are placed on the nodes.

    The kubeconfig is exported so you can interact with your cluster using kubectl or other Kubernetes tools. You'll need this to deploy your training workloads to the cluster.

    When you run this Pulumi program, it will provision the required infrastructure on your cloud provider. In this case, we are assuming the use of AWS as it is the standard provider for EKS clusters.

    Before you can run this code, ensure that you have the Pulumi CLI installed and properly configured for Python, and that your AWS credentials are set up. You can then run this program using the pulumi up command to deploy the resources.

    Remember, this is a general setup, and depending on your exact workload and requirements, you might want to tweak instance types, IAM roles, and other configurations accordingly.