Adding hosts

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You can use the Ceph Orchestrator with Cephadm in the backend to add hosts to an existing IBM Storage Ceph.

Prerequisites

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A running IBM Storage Ceph cluster.
Root-level access to all nodes in the storage cluster.
Register the nodes to the CDN and attach subscriptions.
Ansible user with sudo and passwordless ssh access to all nodes in the storage cluster.
The IP addresses of the new hosts should be updated in /etc/hosts file.

Procedure

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From the Ceph administration node, log into the Cephadm shell:

Example
```
[root@host01 ~]# cephadm shell
```

Extract the cluster’s public SSH keys to a folder:

Syntax

ceph cephadm get-pub-key > ~/PATH

Example

[ceph: root@host01 /]# ceph cephadm get-pub-key > ~/ceph.pub

Copy Ceph cluster’s public SSH keys to the root user’s authorized_keys file on the new host:

Syntax
```
ssh-copy-id -f -i ~/PATH root@HOST_NAME_2
```
Example
```
[ceph: root@host01 /]# ssh-copy-id -f -i ~/ceph.pub root@host02
```
From the Ansible administration node, add the new host to the Ansible inventory file. The default location for the file is /usr/share/cephadm-ansible/hosts. The following example shows the structure of a typical inventory file:

Example
```
host01
host02
host03

[admin]
host00
```
Note: If you have previously added the new host to the Ansible inventory file and run the preflight playbook on the host, skip to step 6.

Run the preflight playbook with the --limit option:

Syntax

ansible-playbook -i INVENTORY_FILE cephadm-preflight.yml --extra-vars "ceph_origin=ibm" --limit NEWHOST

Example

[ansible@admin cephadm-ansible]$ ansible-playbook -i hosts cephadm-preflight.yml --extra-vars "ceph_origin=ibm" --limit host02

The preflight playbook installs podman, lvm2, chrony, and cephadm on the new host. After installation is complete, cephadm resides in the /usr/sbin/ directory.

From the Ceph administration node, log into the Cephadm shell:

Example
```
[root@host01 ~]# cephadm shell
```

Use the cephadm orchestrator to add hosts to the storage cluster:

Syntax

ceph orch host add HOST_NAME IP_ADDRESS_OF_HOST [--label=LABEL_NAME_1,LABEL_NAME_2]

Example

[ceph: root@host01 /]# ceph orch host add host02 10.10.128.70 --labels=mon,mgr

Verification

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List the hosts:

Example

[ceph: root@host01 /]# ceph orch host ls

Reference

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