Chapter 4. Client Installation
Red Hat Ceph Storage supports the following types of Ceph clients:
- Ceph CLI
- The Ceph command-line interface (CLI) enables administrators to execute Ceph administrative commands. See Section 4.2, “Ceph Command-line Interface Installation” for information on installing the Ceph CLI.
- Block Device
- The Ceph Block Device is a thin-provisioned, resizable block device. See Section 4.3, “Ceph Block Device Installation” for information on installing Ceph Block Devices.
- Object Gateway
- The Ceph Object Ǵateway provides its own user management and Swift- and S3-compliant APIs. See Section 4.4, “Ceph Object Gateway Installation” for information on installing Ceph Object Gateways.
In addition, the ceph-ansible utility provides the ceph-client role that copies the Ceph configuration file and the administration keyring to nodes. See Section 4.1, “Installing the ceph-client role” for details.
To use Ceph clients, you must have a Ceph cluster storage running, preferably in the active + clean state.
In addition, before installing the Ceph clients, ensure to perform the tasks listed in the Figure 2.1, “Prerequisite Workflow” section.
4.1. Installing the ceph-client role
The ceph-client role copies the Ceph configuration file and administration keyring to a node. In addition, you can use this role to create custom pools and clients.
To deploy the ceph-client role by using Ansible, see the Red Hat Ceph Storage 2 Installation Guide for Red Hat Enterprise Linux.
4.2. Ceph Command-line Interface Installation
The Ceph command-line interface (CLI) is provided by the ceph-common package and includes the following utilities:
-
ceph -
ceph-authtool -
ceph-dencoder -
rados
To install the Ceph CLI:
- On the client node, enable the Tools repository.
On the client node, install the
ceph-commonpackage:$ sudo apt-get install ceph-common
From the initial monitor node, copy the Ceph configuration file, in this case
ceph.conf, and the administration keyring to the client node:Syntax
# scp /etc/ceph/<cluster_name>.conf <user_name>@<client_host_name>:/etc/ceph/ # scp /etc/ceph/<cluster_name>.client.admin.keyring <user_name>@<client_host_name:/etc/ceph/
Example
# scp /etc/ceph/ceph.conf root@node1:/etc/ceph/ # scp /etc/ceph/ceph.client.admin.keyring root@node1:/etc/ceph/
Replace
<client_host_name>with the host name of the client node.
4.3. Ceph Block Device Installation
The following procedure shows how to install and mount a thin-provisioned, resizable Ceph Block Device.
Ceph Block Devices must be deployed on separate nodes from the Ceph Monitor and OSD nodes. Running kernel clients and kernel server daemons on the same node can lead to kernel deadlocks.
Before you start
- Ensure to perform the tasks listed in the Section 4.2, “Ceph Command-line Interface Installation” section.
- If you use Ceph Block Devices as a back end for virtual machines (VMs) that use QEMU, increase the default file descriptor. See the Ceph - VM hangs when transferring large amounts of data to RBD disk Knowledgebase article for details.
Installing Ceph Block Devices by Using the Command Line
Create a Ceph Block Device user named
client.rbdwith full permissions to files on OSD nodes (osd 'allow rwx') and output the result to a keyring file:ceph auth get-or-create client.rbd mon 'allow r' osd 'allow rwx pool=<pool_name>' \ -o /etc/ceph/rbd.keyring
Replace
<pool_name>with the name of the pool that you want to allowclient.rbdto have access to, for examplerbd:$ sudo ceph auth get-or-create \ client.rbd mon 'allow r' osd 'allow rwx pool=rbd' \ -o /etc/ceph/rbd.keyring
See the User Management section in the Red Hat Ceph Storage Administration Guide for more information about creating users.
Create a block device image:
rbd create <image_name> --size <image_size> --pool <pool_name> \ --name client.rbd --keyring /etc/ceph/rbd.keyring
Specify
<image_name>,<image_size>, and<pool_name>, for example:$ rbd create image1 --size 4096 --pool rbd \ --name client.rbd --keyring /etc/ceph/rbd.keyring
WarningThe default Ceph configuration includes the following Ceph Block Device features:
-
layering -
exclusive-lock -
object-map -
deep-flatten -
fast-diff
If you use the kernel RBD (
krbd) client, you will not be able to map the block device image because the current kernel version included in Red Hat Enterprise Linux 7.3 does not supportobject-map,deep-flatten, andfast-diff.To work around this problem, disable the unsupported features. Use one of the following options to do so:
Disable the unsupported features dynamically:
rbd feature disable <image_name> <feature_name>
For example:
# rbd feature disable image1 object-map deep-flatten fast-diff
-
Use the
--image-feature layeringoption with therbd createcommand to enable onlylayeringon newly created block device images. Disable the features be default in the Ceph configuration file:
rbd_default_features = 1
This is a known issue, for details see the Release Notes Red Hat Ceph Storage 2.2.
All these features work for users that use the user-space RBD client to access the block device images.
-
Map the newly created image to the block device:
rbd map <image_name> --pool <pool_name>\ --name client.rbd --keyring /etc/ceph/rbd.keyring
For example:
$ sudo rbd map image1 --pool rbd --name client.rbd \ --keyring /etc/ceph/rbd.keyring
Use the block device by creating a file system:
mkfs.ext4 -m5 /dev/rbd/<pool_name>/<image_name>
Specify the pool name and the image name, for example:
$ sudo mkfs.ext4 -m5 /dev/rbd/rbd/image1
This can take a few moments.
Mount the newly created file system:
mkdir <mount_directory> mount /dev/rbd/<pool_name>/<image_name> <mount_directory>
For example:
$ sudo mkdir /mnt/ceph-block-device $ sudo mount /dev/rbd/rbd/image1 /mnt/ceph-block-device
For additional details, see the Red Hat Ceph Storage Block Device Guide.
4.4. Ceph Object Gateway Installation
The Ceph object gateway, also know as the RADOS gateway, is an object storage interface built on top of the librados API to provide applications with a RESTful gateway to Ceph storage clusters.
For more information about the Ceph object gateway, see the Object Gateway Guide for Ubuntu.
There are two ways to install the Ceph object gateway:
- Using the Ansible automation application, see Section 4.4.1, “Installing Ceph Object Gateway by using Ansible” for details
- Using the comand-line interface, see Section 4.3.2, "Installing Ceph Object Gateway Manually for details
4.4.1. Installing Ceph Object Gateway by using Ansible
To deploy the Ceph Object Gateway using Ansible, see the Red Hat Ceph Storage 2 Installation Guide for Red Hat Enterprise Linux.
After installation for a multi-site cluster is complete, proceed to the Multi-site chapter in the Object Gateway Guide for Ubuntu for details on configuring a cluster for multi-site.
4.4.2. Installing Ceph Object Gateway Manually
- Enable the Red Hat Ceph Storage 2 Tools repository. For ISO-based installations, see the ISO installation section.
On the Object Gateway node, install the
radosgwpackage:$ sudo apt-get install radosgw
On the initial Monitor node, do the following steps.
Update the Ceph configuration file as follows:
[client.rgw.<obj_gw_hostname>] host = <obj_gw_hostname> rgw frontends = "civetweb port=80" rgw dns name = <obj_gw_hostname>.example.com
Where
<obj_gw_hostname>is a short host name of the gateway node. To view the short host name, use thehostname -scommand.Copy the updated configuration file to the new Object Gateway node and all other nodes in the Ceph storage cluster:
Syntax
$ sudo scp /etc/ceph/<cluster_name>.conf <user_name>@<target_host_name>:/etc/ceph
Example
$ sudo scp /etc/ceph/ceph.conf root@node1:/etc/ceph/
Copy the
<cluster_name>.client.admin.keyringfile to the new Object Gateway node:Syntax
$ sudo scp /etc/ceph/<cluster_name>.client.admin.keyring <user_name>@<target_host_name>:/etc/ceph/
Example
$ sudo scp /etc/ceph/ceph.client.admin.keyring root@node1:/etc/ceph/
On the Object Gateway node, create the data directory:
Syntax
$ sudo mkdir -p /var/lib/ceph/radosgw/<cluster_name>-rgw.`hostname -s`
Example
$ sudo mkdir -p /var/lib/ceph/radosgw/ceph-rgw.`hostname -s`
On the Object Gateway node, add a user and keyring to bootstrap the object gateway:
Syntax
$ sudo ceph auth get-or-create client.rgw.`hostname -s` osd 'allow rwx' mon 'allow rw' -o /var/lib/ceph/radosgw/<cluster_name>-rgw.`hostname -s`/keyring
Example
$ sudo ceph auth get-or-create client.rgw.`hostname -s` osd 'allow rwx' mon 'allow rw' -o /var/lib/ceph/radosgw/ceph-rgw.`hostname -s`/keyring
ImportantWhen you provide capabilities to the gateway key you must provide the read capability. However, providing the Monitor write capability is optional; if you provide it, the Ceph Object Gateway will be able to create pools automatically.
In such a case, ensure to specify a reasonable number of placement groups in a pool. Otherwise, the gateway uses the default number, which might not be suitable for your needs. See Ceph Placement Groups (PGs) per Pool Calculator for details.
On the Object Gateway node, create the
donefile:Syntax
$ sudo touch /var/lib/ceph/radosgw/<cluster_name>-rgw.`hostname -s`/done
Example
$ sudo touch /var/lib/ceph/radosgw/ceph-rgw.`hostname -s`/done
On the Object Gateway node, change the owner and group permissions:
$ sudo chown -R ceph:ceph /var/lib/ceph/radosgw $ sudo chown -R ceph:ceph /var/log/ceph $ sudo chown -R ceph:ceph /var/run/ceph $ sudo chown -R ceph:ceph /etc/ceph
For storage clusters with custom names, as
root, add the the following line:Syntax
$ sudo echo "CLUSTER=<custom_cluster_name>" >> /etc/default/ceph
Example
$ sudo echo "CLUSTER=test123" >> /etc/default/ceph
On the Object Gateway node, open TCP port 80:
$ sudo iptables -I INPUT 1 -i <network_interface> -p tcp -s <ip_address>/<netmask> --dport 80 -j ACCEPT
On the Object Gateway node, start and enable the
ceph-radosgwprocess:Syntax
$ sudo systemctl enable ceph-radosgw.target $ sudo systemctl enable ceph-radosgw@rgw.<rgw_hostname> $ sudo systemctl start ceph-radosgw@rgw.<rgw_hostname>
Example
$ sudo systemctl enable ceph-radosgw.target $ sudo systemctl enable ceph-radosgw@rgw.node1 $ sudo systemctl start ceph-radosgw@rgw.node1
Once installed, the Ceph Object Gateway automatically creates pools if the write capability is set on the Monitor. See the Pools chapter in the Storage Strategies Guide for information on creating pools manually.
