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ADR 006: Lightweight Kubernetes (K3s) on Proxmox VM

Context

We need a Kubernetes environment for our FastAPI application. The Proxmox host is resource-constrained (Ryzen 5, 4 Cores). We evaluated using standard Kubernetes (K8s) versus K3s, and LXC containers versus a full Virtual Machine (VM).

Decision

We will provision a dedicated Debian Virtual Machine (VM) on Proxmox and install K3s (Lightweight Kubernetes).

Consequences

  • Positive: K3s reduces overhead compared to K8s, fitting our CPU limits. Using a VM instead of an LXC container ensures proper kernel isolation required for Kubernetes networking (CNI) and cgroups.
  • Negative: A VM has slightly higher base memory and boot-time overhead than an LXC container.