Edge computing presents complex challenges when managing many sites in geographically displaced locations. Use zero touch provisioning (ZTP) and GitOps to provision and manage sites at the far edge of the network.
Today, service providers want to deploy their infrastructure at the edge of the network. This presents significant challenges:
How do you handle deployments of many edge sites in parallel?
What happens when you need to deploy sites in disconnected environments?
How do you manage the lifecycle of large fleets of clusters?
Zero touch provisioning (ZTP) and GitOps meets these challenges by allowing you to provision remote edge sites at scale with declarative site definitions and configurations for bare-metal equipment. Template or overlay configurations install OKD features that are required for CNF workloads. The full lifecycle of installation and upgrades is handled through the ZTP pipeline.
ZTP uses GitOps for infrastructure deployments. With GitOps, you use declarative YAML files and other defined patterns stored in Git repositories. Red Hat Advanced Cluster Management (RHACM) uses your Git repositories to drive the deployment of your infrastructure.
GitOps provides traceability, role-based access control (RBAC), and a single source of truth for the desired state of each site. Scalability issues are addressed by Git methodologies and event driven operations through webhooks.
You start the ZTP workflow by creating declarative site definition and configuration custom resources (CRs) that the ZTP pipeline delivers to the edge nodes.
The following diagram shows how ZTP works within the far edge framework.
Red Hat Advanced Cluster Management (RHACM) manages clusters in a hub-and-spoke architecture, where a single hub cluster manages many spoke clusters. Hub clusters running RHACM provision and deploy the managed clusters by using zero touch provisioning (ZTP) and the assisted service that is deployed when you install RHACM.
The assisted service handles provisioning of OKD on single node clusters, three-node clusters, or standard clusters running on bare metal.
A high-level overview of using ZTP to provision and maintain bare-metal hosts with OKD is as follows:
A hub cluster running RHACM manages an internal registry that mirrors the OKD release images. RHACM uses the internal registry to provision the managed clusters.
You manage the bare-metal hosts in a YAML format inventory file, versioned in a Git repository.
You make the hosts ready for provisioning as managed clusters, and use RHACM and the assisted service to install the bare-metal hosts on site.
Installing and deploying the clusters is a two-stage process, involving an initial installation phase, and a subsequent configuration phase. The following diagram illustrates this workflow: