Edge Delta on Specific Nodes

Overview

In a Kubernetes cluster, specifying which nodes to install certain workloads on can be crucial for several reasons. One might want to use a node selector to ensure that workloads are executed only on nodes with specific capabilities or characteristics. For instance, if certain nodes are optimized for logging operations or equipped with particular hardware accelerators, such as GPUs, you would want to deploy workloads that require these features only to the relevant nodes. This targeted deployment can deliver more efficient resource utilization and improve performance for resource-intensive applications.

Moreover, deploying on specific nodes can help achieve compliance and security requirements by ensuring certain workloads or data reside on nodes with enhanced security measures or within specific geographic locations. This approach might also be used to balance workloads across nodes with different performance profiles to ensure high availability and fault tolerance.

However, there are some drawbacks to this configuration. Implementing a node selector or node affinity can lead to increased complexity in managing your Kubernetes cluster. It requires additional administrative overhead to accurately label and maintain nodes, manage node-specific configurations, and periodically reassess node capabilities as your environment changes. Additionally, heavily restricting workloads to specific nodes can lead to resource under-utilization if those nodes are not consistently running at full capacity. This can negate some of the main advantages of a Kubernetes environment, such as automatic scaling and efficient resource allocation. Thus, while targeting specific nodes can offer significant advantages in terms of performance and regulatory compliance, it should be implemented with careful planning and ongoing assessment to maintain the balance between targeted deployments and overall cluster efficiency.

See Edge Delta in Uneven Deployments.

Run on Specific Nodes

If you need to run the fleet on specific nodes in your cluster, add a node selector or nodeAffinity section to your pod config file. For example, if the desired nodes are labeled as logging=edgedelta, then adding the following nodeSelector will restrict the Fleet pods to nodes that have the logging=edgedelta label.

spec:  
    nodeSelector:    
        logging: edgedelta

To learn more, see this article.