363.2 Ceph Storage Clusters (weight: 8)

Tech Tutorial: 363.2 Ceph Storage Clusters (weight: 8) #

Introduction #

Ceph is a highly resilient and scalable storage solution that allows enterprises to build and manage vast amounts of data in a distributed storage architecture. In this tutorial, we will explore how to set up and manage a basic Ceph storage cluster. We will cover some essential commands and configurations required for day-to-day management and troubleshooting of Ceph clusters.

Exam Objective: #

  • Understand the architecture and deployment of Ceph storage clusters.
  • Be able to perform basic Ceph cluster operations and maintenance.

Key Knowledge Areas: #

  • Ceph cluster architecture
  • Basic Ceph commands and usage
  • Monitoring and maintaining a Ceph cluster

Utilities: #

  • ceph
  • rados
  • rbd
  • ceph-mon
  • ceph-osd

Step-by-Step Guide #

Step 1: Understanding Ceph Components #

Ceph primarily consists of the following components:

  • Ceph OSDs (Object Storage Daemons): Stores data as objects on storage nodes.
  • Ceph Monitor (ceph-mon): Keeps a master copy of the cluster map.
  • Ceph Manager (ceph-mgr): Provides additional monitoring and management.
  • Ceph RADOS Block Device (RBD): Allows block-level storage access.

Step 2: Setting Up a Ceph Cluster #

Before beginning, ensure that you have at least three nodes to set up a minimal cluster.

  1. Install Ceph on all nodes:
sudo apt update
sudo apt install ceph-deploy
  1. Create a new cluster directory and cluster configuration:
mkdir my-ceph-cluster
cd my-ceph-cluster
ceph-deploy new node1 node2 node3
  1. Install Ceph on all nodes:
ceph-deploy install node1 node2 node3
  1. Deploy the initial monitor(s) and gather the keys:
ceph-deploy mon create-initial

Step 3: Adding OSDs #

OSDs are the heart of the Ceph storage, handling the storage of data in terms of objects.

ceph-deploy osd create --data /dev/sdb node1

Replace /dev/sdb with your storage drive identifier.

Step 4: Basic Ceph Commands #

  • Check cluster health:
ceph health
  • List all OSDs:
ceph osd ls
  • Get cluster status:
ceph -s

Step 5: Using RADOS and RBD Utilities #

  • Create a pool with RADOS:
ceph osd pool create mypool 128 128
  • List all pools:
rados lspools
  • Create an RBD (block device):
rbd create mypool/myvolume --size 1024
  • Map the RBD block device:
rbd map mypool/myvolume

Step 6: Monitoring and Maintaining #

  • Monitor cluster utilization:
ceph df
  • Check OSD status:
ceph osd stat
  • Repairing OSDs:
ceph osd repair osd.<osd-id>

Replace <osd-id> with the actual OSD ID.

Conclusion #

In this tutorial, we’ve gone through the basics of setting up and managing a Ceph storage cluster. The commands and procedures outlined provide a foundation for further exploration and management of more complex Ceph functionalities. Ceph’s scalable and resilient nature makes it an ideal solution for large-scale storage requirements in modern data centers.