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Samuel Ajisafe
Samuel Ajisafe

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Ceph Setup - Ground Up

Introduction
Ceph is a free and open-source software-defined storage platform that provides object storage, block storage, and file storage built on a common distributed cluster foundation.

For us, it is meant to serve as an alternative to AWS S3 and MinIO.

Ceph Documentation

Node Setup(Server)
For each node(server) that will be added to the Ceph cluster, it ideal to have 2 storage allocated to it.

The first storage should be small and dedicated to the system root

The second should be as large as you want for the purpose of object storage and will be mapped as a device and used for OSD in Ceph. Then use the below command to extend it

Make sure to create LVM for the first storage. Don’t tamper on the second storage as Ceph will adjust it as necessary.

Once the OS is installed and configured, Use the below command to extend the lvm accordingly.

sudo lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
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Then use the below command to resize the filesystem accordingly. This will ensure that your root partition has adequate storage for ceph download later.

sudo resize2fs /dev/ubuntu-vg/ubuntu-lv
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Use the below command to view the sizing status

lsblk
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Installing Cephadm
Install cephadm command so we can use it to bootstrap our ceph setup. Follow the below steps to achieve this.

Update apt packages first to have latest version of the components.

sudo apt update
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Install chrony for network time syncing. Required.

sudo apt install chrony
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Check the Chrony was successfully installed

chronyc -v
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Install docker

sudo apt  install  docker.io
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Confirm that docker was successfully installed

docker -v
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Confirm the LVM commands is available

pvcreate
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Confirm that python3 is running

python3 --version
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If you wish, make python command resolve to python3. Not required

sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 2
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Install CephAdmin. This is what you will use to bootstrap ceph

sudo apt install -y cephadm
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Confirm that Cephadmin is successfully installed

which cephadm
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Bootstrap Ceph
After installing Cephadm, we will now use it to bootstrap our ceph setup. You need internet connection for the following steps as ceph will be downloaded as part of the steps.

Bootstrap Ceph using cephadm

replace with the ip address of where the monitor engine is running. Since this is a single host, all the ceph engines are running from the same host; so, i will just replace this with the ip address of the host.

You can also change the initial dashboard user from admin to whatever else you wish

You can also change the initial dashboard password from exampleXX123 to whatever else you wish

sudo cephadm bootstrap --mon-ip <host-ip-addr> --dashboard-password-noupdate --initial-dashboard-user admin --initial-dashboard-password exampleXX123
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Once Ceph has been successfully bootstrapped, you should see the details of the dashboard. However, below are some relevant Ceph services you should note. You need to wait for some minutes for some of these services to fully start. You can map the ip address to a domain as you wish.

_Ceph Dashboard - https://10.10.0.125.8443

Ceph Exporter - http://10.10.0.125:9283/metrics

Prometheus - http://10.10.0.125:9095/metrics

Alert Manager - http://10.10.0.125:9093/

Grafana - https://10.10.0.125:3000/

API Documentation - https://10.10.0.125:8443/docs_

You need to install additional packages in order to use other ceph commands. This is for convenience. Install ceph-common, rados-gw, ceph base packages so you can execute ceph commands.

sudo cephadm add-repo --release octopus
sudo cephadm install ceph-common
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Check status and version of ceph

sudo ceph -s
sudo ceph -v
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Confirm Ceph configuration file

ls -l  /etc/ceph
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Check all Ceph processes running

sudo ceph orch ps
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Check Ceph Health Status

ceph health detail
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In order to successfully setup the rgw gateway, you must eliminate all errors and warnings from the dashboard. A key reason rgw gateway will not setup is if there are still errors in the Dashboard.

Settings(For a single node cluster to help remove the health warnings)

Turn off the warning for pools without replication

sudo ceph config set mon mon_warn_on_pool_no_redundancy false
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Allow pool deletion, turn off the settings.

sudo ceph config set mon mon_allow_pool_delete true
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Reconfigure default osd pool size

sudo ceph config set global osd_pool_default_size 1
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Setup Ceph OSD(This can be done from the interface or from terminal as below)
View devices available to your Ceph cluster for OSD

sudo ceph orch device ls
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Zap(format) the device that you want to map OSD to.

sudo ceph orch device zap cephadmin </dev/sdb> --force
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To see all OSDs configured on your Ceph Cluster

sudo ceph osd tree
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View all available pools

sudo ceph osd lspools
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Add OSDs

sudo ceph orch daemon add osd <hostname>:</dev/sdb>
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Create Pools
Ensure that the value for pg-size and pgp-size is a multiple of 2

sudo ceph osd pool create <pool-name> <pg-size> <pgp-size>
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RGW Setup

sudo radosgw-admin realm create --rgw-realm=<realm-name> --default
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sudo radosgw-admin zonegroup create --rgw-zonegroup=<zonegroup-name>  --master --default
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sudo radosgw-admin zone create --rgw-zonegroup=<zonegroup-name> --rgw-zone=<zone-name> --master --default
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sudo radosgw-admin period update --rgw-realm=<realm-name> --commit
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sudo ceph orch apply rgw <realm-name>  <zone-name> --placement="<num-daemons>  <host1>"
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e.g. The below will create a rgw gateway with global as realm and tutorial as the zone with 1 placement(daemon) on the host 10.10.0.125.

sudo ceph orch apply rgw global tutorial --placement="1 10.10.0.125”

Create S3 users for RGW.
Take note of the access key and secret key of the user you create especially the user that was created with the --system flag as that is the one whose access key and secret key you will use to activate the object gateway view on the portal.

radosgw-admin user create --uid="<username>" --display-name="<user display name> --system"
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e.g

radosgw-admin user create --uid=devto --display-name="Dev To” --system

View all rgw users

sudo radosgw-admin user list
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Retrieve information about a user

sudo radosgw-admin user info --uid=<user-id>
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e.g The below retrieves all the information about the user iudoh

sudo adosgw-admin user info --uid=devto
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In order for the object gateway to be visible on the portal, you need map the access key and secret key of the user that was created with the --system flag to the ceph dashboard.

Use the below command to do so.

Make sure you copied the access key of the user to a file and the secret key to another file and specify their names accordingly in the below commands.

ceph dashboard set-rgw-api-access-key -i <file-containing-access-key>
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ceph dashboard set-rgw-api-secret-key -i <file-containing-secret-key>
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You should be able to access the Object gateway view on the ceph dashboard now and create more users and buckets.

Per adventure you want information on how to access and push items to the buckets you have created. Use the below link I found online.

How To Configure AWS S3 CLI for Ceph Object Gateway Storage

AWS #CEPH #DevOps #SystemEngineer #SysAdmin #Object #Storage

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