![]() Lifecycle of a PodĪt a very high level, the scheduler controller maintains a queue of pods to be deployed for the cluster and then for each workload in the queue looks for a node with enough available compute resources to fulfill the `request` for that pod and assigns the pod to that node. Additionally Kubernetes allows for a pod priority field to be set. Resource Requests and Limits are the most obvious of these settings, but there are subtle implications to these settings which are not always understood up front.Īll four of the standard service types (Deployments, StatefuSets, Jobs, and DaemonSets) accept a request and a limit for thee different types of compute resources: cpu, memory, and ephemeral-storage. Failure to set these parameters properly can result in performance problems, workload downtimes, and significant overall cluster health issues. Kubernetes uses several pieces of information in scheduling and evicting workloads on the cluster. ![]() Pod Scheduling: Priority and Quality of Service In this post, we’ll cover pod scheduling and how to maintain quality of service by properly specifying resource limitations. There is a lot to cover when it comes to pod design, and rather than try to cover everything in a single post, we’ll cover the basics, and then provide links to more detailed discussions where possible with follow up posts on subjects that we have not yet found quality detailed resources. Containers within a pod share the same lifecycle, and are managed by Kubernetes as a unit. Kubernetes is not only designed for single process cloud native applications, and in order to allow legacy applications to be ported, the authors of Kubernetes created a logical unit that maps very closely to traditional cloud deployments of multi-process applications.Ī pod is a set of containers that are deployed on the same node, get a shared IP, inside the same kernel security group, and can use traditional interprocess communication techniques. ![]() ![]() Containers can be single process, which is where pods come in. Nevertheless, Kubernetes aims to allow new and legacy workloads to take advantage of multiple cooperating processes with pods. As mentioned in a prior post, Kubernetes is at its best when managing single process containers. ![]()
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