Tuesday, January 3, 2023

Installing Ansible on CentOS for vSphere First Class Disks

I've been wanting to play with first class disks for some time now, and needed a means of doing so. While there are many ways to interact with vSphere APIs, Ansible provides a means of automation that has some key advantages (primarily in that it is free). This post will get us started on installing Ansible in a CentOS 9 environment, as well as installing the VMware Community modules and deploying a runbook that will create a first class disk.

The first thing we'll need to do is install Ansible. With CentOS 9, we'll need to add a repository in order to install it.

sudo yum install epel-release
sudo yum update
sudo yum install ansible
Once installed, we'll need to install some additional modules - python package manager (pip3), python SDK for VMware API (PyVmomi), and the VMware Ansible collection:

sudo yum install python3-pip -y
pip3 install PyVmomi
ansible-galaxy collection install vmware.vmware_rest
Once complete, we can work on updating our Ansible hosts file and write our first playbook. The hosts file for Ansible is located at /etc/ansible/hosts. Using the text editor of your choice, add the hostname or IP address of your vCenter server to the last line of the file.

To prepare the VMware environment, ensure that SSH is enabled on both the vCenter server and host(s) that you plan on running the playbook against. I took the extra step of starting an SSH session to each (root@vCenterIP and root@ESXiHostIP) to log the key thumbprint for each; while this may not be necessary, it's a force of habit for me.

Finally, it's time to write the First Class Disk playbook. The playbook will create a 1GB FCD based VMDK onto the datastore of our choosing. This will require the vCenter username and password. While I suggest using a variable file to store this information (shorthand "vars"), for the purpose of this example I will use plain text. I used the command "vi fcd.yml" and wrote the following:

- name: FCD
  hosts: localhost
  become: false
  gather_facts: false
    - community.vmware
    - name: create disk
        hostname: '(vCenter IP address or FQDN)'
        username: 'administrator@vsphere.local'
        password: '(enter password here)'
        validate_certs: no
        datastore_name: 'Datastore1'
        disk_name: '1GBDisk'
        size: '1GB'
        state: present
      delegate_to: localhost

Let's break this down a bit:
Hostname: Use the vCenter IP address or FQDN.
Username: Typically administrator@vsphere.local but can be a domain account. Note that as we are carrying out a vSphere action, we do not want to use "root" here.
Password: The password for the above username.
validate_certs: This was a work around for an error that I received when first trying to run the playbook. There may be other ways around it, but adding this line seems to do the trick.
disk_name: I'm not entirely certain this variable works, but it is called out in the Ansible example.

Once this is written, we can execute the playbook with: ansible-playbook fcd.yml
This should yield the following result:

PLAY [FCD] *********************************************************************

TASK [create disk] *************************************************************
ok: [localhost]

PLAY RECAP *********************************************************************
localhost                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
When we log into vCenter, a new folder on the target datastore should have a label of "fcd", and we can see the new VMDK:

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