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Zinovy Naumov
Zinovy Naumov

Mastering Ceph: How to Optimize Storage Performance and ROI with Ceph


Mastering Ceph by Nick Fisk PDF: A Comprehensive Guide to Learn and Deploy Ceph Storage




Ceph is a popular open-source distributed storage system that provides scalable, reliable, and high-performance storage for various types of data. Whether you need to store block devices, file systems, or objects, Ceph can handle it all with ease. However, learning how to install, configure, use, and administer Ceph can be challenging, especially if you are new to distributed storage systems.




Mastering Ceph By Nick Fisk Pdf



That's why you need a comprehensive guide that covers everything you need to know about Ceph storage. And that's exactly what Mastering Ceph by Nick Fisk PDF is. It is a book that teaches you how to master Ceph storage from scratch. It covers the basics of Ceph architecture and components, the installation and configuration of Ceph cluster, the usage and administration of Ceph storage types and interfaces, and the monitoring and troubleshooting of Ceph cluster and storage. It also provides practical examples, tips, and best practices to help you get the most out of Ceph storage.


If you are looking for a book that can help you learn and deploy Ceph storage in a fast and efficient way, Mastering Ceph by Nick Fisk PDF is the book for you. It is suitable for anyone who wants to use Ceph storage for their personal or professional projects, such as system administrators, developers, engineers, or enthusiasts. However, you should have some basic knowledge of Linux, networking, and storage concepts before reading this book.


Overview of Ceph Architecture and Components




Ceph is a distributed storage system that consists of several components that work together to provide scalable, reliable, and high-performance storage. In this section, we will give an overview of the main components of Ceph architecture and how they interact with each other.


Ceph Cluster and Daemons




A Ceph cluster is a collection of nodes that run various daemons that provide storage services. The main types of daemons are:



  • Ceph Monitor (ceph-mon): This daemon is responsible for maintaining the cluster map, which contains information about the cluster state, such as the cluster membership, the monitor quorum, the OSD map, the CRUSH map, etc. The monitor daemons also provide consensus among the cluster members using the Paxos algorithm. A Ceph cluster requires at least three monitor daemons to form a quorum and operate normally.



  • Ceph Manager (ceph-mgr): This daemon is responsible for providing additional management and monitoring capabilities for the cluster, such as collecting and exposing metrics, generating alerts, managing dashboard and web UI, orchestrating cluster updates and upgrades, etc. A Ceph cluster requires at least one manager daemon to function properly, but it is recommended to have two or more for redundancy.



  • Ceph OSD (ceph-osd): This daemon is responsible for storing data on local disks and providing access to data via network. The OSD daemons also handle data replication, erasure coding, recovery, rebalancing, etc. A Ceph cluster can have hundreds or thousands of OSD daemons to scale up the storage capacity and performance.



  • Ceph MDS (ceph-mds): This daemon is responsible for providing metadata service for Ceph File System (CephFS), which is a POSIX-compliant file system that uses Ceph as its underlying storage. The MDS daemons manage the file system namespace, such as directories, files, attributes, etc. A CephFS file system can have one or more active MDS daemons to handle metadata requests from clients.



Ceph Storage Types and Interfaces




Ceph provides three types of storage that can be accessed via different interfaces. The main types of storage are:



  • Ceph Block Device (RBD): This is a virtual block device that can be attached to a client machine as a local disk. RBD uses RADOS (Reliable Autonomic Distributed Object Store), which is the core object storage layer of Ceph, to store data as objects on OSDs. RBD supports features such as thin provisioning, copy-on-write cloning, snapshotting, encryption, etc. RBD can be accessed via librbd library or kernel module from Linux clients or via iSCSI protocol from Windows or VMware clients.



  • Ceph File System (CephFS): This is a POSIX-compliant file system that uses Ceph as its underlying storage. CephFS uses RADOS to store file data as objects on OSDs and uses MDS to store file metadata in separate pools. CephFS supports features such as quotas, permissions, snapshots, etc. CephFS can be accessed via kernel module or FUSE client from Linux clients or via NFS or SMB protocol from Windows clients.



  • Ceph Object Storage (RGW): This is an object storage service that provides a RESTful API compatible with S3 or Swift protocols. RGW uses RADOS to store object data and metadata on OSDs. RGW supports features such as versioning, lifecycle management, encryption, etc. RGW can be accessed via HTTP or HTTPS protocol from any client that supports S3 or Swift API.



Ceph Data Placement and Replication




to distribute data evenly and efficiently without relying on a central lookup table or a single point of failure. CRUSH uses two main concepts to achieve this: CRUSH map and placement groups.



  • CRUSH map: This is a hierarchical description of the cluster topology and the rules for data placement and replication. The CRUSH map defines the types of devices (such as OSDs, disks, hosts, racks, etc.), the relationships among them (such as hierarchy, weight, failure domain, etc.), and the policies for data replication (such as replication factor, erasure coding profile, etc.). The CRUSH map is stored on the monitor daemons and can be updated dynamically as the cluster changes.



  • Placement groups (PGs): These are logical partitions of data that are mapped to a subset of OSDs by the CRUSH algorithm. Each PG has a unique identifier that consists of a pool ID and a PG number. Each PG also has a state that reflects its health and status. For example, a PG can be active (healthy and serving requests), peering (recovering or rebalancing), degraded (missing some replicas), etc. The number of PGs per pool can be configured based on the expected size and performance of the pool.



Ceph uses CRUSH to calculate which PGs are responsible for storing which objects and which OSDs are responsible for storing which PGs. This way, Ceph can ensure that data is replicated and distributed across OSDs according to the CRUSH rules and policies. Ceph can also handle failures and additions of OSDs by recalculating the PG mappings and relocating the data accordingly.


Installing and Configuring Ceph Cluster




In this section, we will discuss how to install and configure a Ceph cluster using different methods and tools. We will also cover some basic cluster management and operations that are essential for running a Ceph cluster.


Hardware and Software Requirements




Before installing a Ceph cluster, you need to make sure that you have the appropriate hardware and software for your nodes and disks. Here are some general guidelines for hardware and software requirements:



Component


Minimum


Recommended


CPU


2 cores


4 cores or more


RAM


2 GB


4 GB or more


Disk


10 GB for OS partition20 GB for data partition


SSD for OS partitionHDD or SSD for data partitionNVMe for journal or cache partition


Network


1 Gbps


10 Gbps or moreBonding or teaming for redundancySeparate networks for public and cluster traffic


OS


Linux-based OS with kernel version 4.4 or higherSupported distributions include CentOS, Debian, Ubuntu, etc.


Packages


Ceph packages from official repositories or custom-built sourcesDependencies such as NTP, SSH, Python, etc.


Note that these are only general guidelines and you may need to adjust them according to your specific needs and use cases. For more detailed information on hardware and software requirements, please refer to the official Ceph documentation.


Deployment Methods and Tools




There are different methods and tools that you can use to deploy a Ceph cluster. The most common ones are:



  • Manual installation using ceph-deploy: This is a simple and straightforward method that involves installing Ceph packages on each node manually using ceph-deploy tool. ceph-deploy is a command-line tool that automates some of the tasks such as creating SSH keys, copying configuration files, starting daemons, etc. However, you still need to configure your network, disks, firewall, etc. manually before using ceph-deploy. This method is suitable for small or test clusters that do not require much customization or automation.



  • Automated installation using Ansible or cephadm: This is a more advanced and flexible method that involves using Ansible or cephadm tool to automate the entire deployment process. Ansible and cephadm are both orchestration tools that can run commands and scripts on multiple nodes remotely using SSH. They can also handle tasks such as network configuration, disk partitioning, firewall rules, etc. automatically. This method is suitable for large or production clusters that require more customization or automation.



For this article, we will use the Ansible method to deploy a Ceph cluster, as it is more widely used and supported by the Ceph community. To use the Ansible method, you need to have the following prerequisites:



  • A control node that runs Ansible and has SSH access to all other nodes



  • At least three monitor nodes that run ceph-mon and ceph-mgr daemons



  • At least three OSD nodes that run ceph-osd daemons and have data disks



  • Optionally, one or more MDS nodes that run ceph-mds daemons for CephFS



  • Optionally, one or more RGW nodes that run ceph-rgw daemons for RGW



  • A Ceph Ansible repository that contains the Ansible playbooks and roles for deploying Ceph



  • A Ceph configuration file that defines the cluster parameters and settings



  • An inventory file that defines the cluster nodes and groups



To deploy a Ceph cluster using Ansible, you need to follow these steps:



  • Clone the Ceph Ansible repository from GitHub to your control node.



  • Edit the Ceph configuration file (ceph.conf) to set the cluster parameters and settings, such as cluster name, network addresses, OSD layout, etc.



  • Edit the inventory file (hosts) to define the cluster nodes and groups, such as mons, osds, mdss, rgws, etc.



  • Run the site.yml playbook to install Ceph packages and start Ceph daemons on all nodes.



  • Verify the cluster status and health using ceph commands or dashboard.



For more detailed information on how to use Ansible to deploy a Ceph cluster, please refer to the official Ceph documentation or the Ceph Ansible GitHub page.


Basic Cluster Management and Operations




Once you have deployed a Ceph cluster, you need to perform some basic management and operations tasks to keep it running smoothly. Some of the common tasks are:



  • Checking cluster status and health: You can use the ceph status or ceph -s command to check the overall status and health of your cluster, such as the number of monitors, OSDs, PGs, pools, etc., the cluster usage and performance metrics, the cluster health warnings and errors, etc. You can also use the ceph health detail command to get more detailed information on the health issues. Alternatively, you can use the dashboard or web UI to view the cluster status and health in a graphical way.



  • Adding and removing nodes and disks: You can use Ansible or cephadm to add or remove nodes and disks from your cluster easily. For example, to add a new OSD node using Ansible, you just need to add it to the inventory file (hosts) under the [osds] group and run the site.yml playbook again. To remove an OSD node using Ansible, you just need to remove it from the inventory file (hosts) and run the purge.yml playbook. Similarly, you can use Ansible or cephadm to add or remove monitor nodes, MDS nodes, RGW nodes, etc.



  • Updating and upgrading cluster software: You can use Ansible or cephadm to update or upgrade your cluster software easily. For example, to update your cluster software using Ansible, you just need to run the rolling_update.yml playbook with the appropriate variables. To upgrade your cluster software using Ansible, you just need to change the Ceph version in the Ceph configuration file (ceph.conf) and run the rolling_update.yml playbook with the appropriate variables. Similarly, you can use Ansible or cephadm to update or upgrade your cluster software from one major release to another.



For more detailed information on how to perform basic cluster management and operations tasks, please refer to the official Ceph documentation or the Ceph Ansible GitHub page.


Using and Administering Ceph Storage Types and Interfaces




storage type and interface, such as creating and deleting pools, images, file systems, users, buckets, etc., mounting and unmounting storage devices on clients, managing features such as snapshots, encryption, versioning, etc.


Ceph Block Device (RBD)




Ceph Block Device (RBD) is a virtual block device that can be attached to a client machine as a local disk. To use RBD, you need to have a pool that stores the RBD images and a client that accesses the RBD images. Here are some common tasks for using and administering RBD:



  • Creating and deleting RBD images: You can use the rbd command to create and delete RBD images in a pool. For example, to create an RBD image named image1 with a size of 10 GB in a pool named rbd, you can use the following command: rbd create image1 --size 10G --pool rbd. To delete an RBD image named image1 from a pool named rbd, you can use the following command: rbd rm image1 --pool rbd.



  • Mounting and unmounting RBD images on clients: You can use the rbd command to map and unmap RBD images to local devices on clients. For example, to map an RBD image named image1 from a pool named rbd to a local device named /dev/rbd0, you can use the following command: rbd map image1 --pool rbd. To unmap an RBD image from a local device named /dev/rbd0, you can use the following command: rbd unmap /dev/rbd0. Alternatively, you can use the mount and umount commands to mount and unmount RBD images as file systems on clients.



  • Resizing, cloning, and snapshotting RBD images: You can use the rbd command to resize, clone, and snapshot RBD images. For example, to resize an RBD image named image1 from a pool named rbd to a new size of 20 GB, you can use the following command: rbd resize image1 --size 20G --pool rbd. To clone an RBD image named image1 from a pool named rbd to a new image named image2 in the same pool, you can use the following command: rbd clone image1 image2 --pool rbd. To create a snapshot of an RBD image named image1 from a pool named rbd, you can use the following command: rbd snap create image1@snap1 --pool rbd. To list the snapshots of an RBD image named image1 from a pool named rbd, you can use the following command: rbd snap ls image1 --pool rbd.



code>. To decrypt an RBD image named image1 from a pool named rbd with a passphrase stored in a file named /etc/ceph/keyfile, you can use the following command: rbd encryption load --passphrase-file /etc/ceph/keyfile image1 --pool rbd.


For more detailed information on how to use and administer RBD, please refer to the official Ceph documentation or the rbd man page.


Ceph File System (CephFS)




Ceph File System (CephFS) is a POSIX-compliant file system that uses Ceph as its underlying storage. To use CephFS, you need to have a pool that stores the file data and a pool that stores the file metadata. You also need to have one or more MDS daemons that provide the metadata service for CephFS. Here are some common tasks for using and administering CephFS:



  • Creating and deleting CephFS file systems and pools: You can use the ceph fs command to create and delete CephFS file systems and pools. For example, to create a CephFS file system named cephfs with a data pool named cephfs_data and a metadata pool named cephfs_metadata, you can use the following command: ceph fs new cephfs cephfs_metadata cephfs_data. To delete a CephFS file system named cephfs, you can use the following command: ceph fs rm cephfs --yes-i-really-mean-it.



  • Mounting and unmounting CephFS on clients: You can use the mount and umount commands to mount and unmount CephFS as file systems on clients. For example, to mount a CephFS file system named cephfs to a local directory named /mnt/cephfs, you can use the following command: mount -t ceph mon1:6789,mon2:6789,mon3:6789:/ /mnt/cephfs -o name=admin,secret=AQATSKdNGBnwLhAAnNDKnH65FmVKpXZJVasUeQ==. To unmount a CephFS file system from a local directory named /mnt/cephfs, you can use the following command: umount /mnt/cephfs. Alternatively, you can use the ceph-fuse command to mount and unmount CephFS using FUSE (Filesystem in Userspace) on clients.



code>. To set the permission of a file named /mnt/cephfs/file1 to 644, you can use the following command: chmod 644 /mnt/cephfs/file1. To create a snapshot of a directory named /mnt/cephfs/dir1, you can use the following command: mkdir /mnt/cephfs/dir1/.snap/snap1. To list the snapshots of a directory named /mnt/cephfs/dir1, you can use the following command: ls /mnt/cephfs/dir1/.snap.


For more detailed information on how to use and administer CephFS, please refer to the official Ceph documentation or the ceph fs man page.


Ceph Object Storage (RGW)




Ceph Object Storage (RGW) is an object storage service that provides a RESTful API compatible with S3 or Swift protocols. To use RGW, you need to have a pool that stores the RGW objects and metadata. You also need to have one or more RGW daemons that provide the object storage service. Here are some common tasks for using and administering RGW:



Creating and deleting RGW users and buckets: You can use the radosgw-admin command to create and delete RGW users and buckets. For example, to create a RGW user named user1 with an access key and a secret key, you can use the following command: radosgw-admin user create --uid=user1 --display-name="User 1" --access-key=AKIAIOSFODNN7EXAMPLE --secret-key=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY. To delete a RGW user named user1, you can use the following com


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