sergealexandre / topolvm

Capacity-aware CSI plugin for Kubernetes

TopoLVM

TopoLVM is a CSI plugin using LVM for Kubernetes. It can be considered as a specific implementation of local persistent volumes using CSI and LVM.

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• Project Status: Testing for production
• Conformed CSI version: 1.1.0

Supported environments

• Kubernetes
  • 1.14
  • 1.15
  • 1.16
• Node OS
  • Linux with LVM2
• Filesystems
  • ext4
  • xfs
  • btrfs

Features

• Dynamic provisioning: Volumes are created dynamically when PersistentVolumeClaim objects are created.
• Raw block volume: Volumes are available as block devices inside containers.
• Ephemeral inline volume: Volumes can be directly embbeded in the Pod specification.
• Topology: TopoLVM uses CSI topology feature to schedule Pod to Node where LVM volume exist.
• Extended scheduler: TopoLVM extends the general Pod scheduler to prioritize Nodes having larger storage capacity.
• Volume metrics: Usage stats are exported as Prometheus metrics from kubelet.

Planned features

• Volume Expansion: When support for Kubernetes 1.16 will be added.
• Snapshot: When we want it.

Programs

A diagram of components is available in docs/design.md.

This repository contains these programs:

• topolvm-controller: CSI controller service.
• topolvm-scheduler: A scheduler extender for TopoLVM.
• topolvm-node: CSI node service.
• lvmd: gRPC service to manage LVM volumes.

lvmd is a standalone program that should be run on Node OS as a systemd service. Other programs are packaged into a container image.

Getting started

A demonstration of TopoLVM running on kind (Kubernetes IN Docker) is available at example directory.

For production deployments, see deploy directory.

User manual is at docs/user-manual.md.

Documentation

docs directory contains documents about designs and specifications.