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Ruben S. Montero edited this page Aug 14, 2024 · 23 revisions

Single Front-end & Shared Storage

This scenario is a variation of the local storage setup. Here, the storage for virtual machines (VMs) and the image repository are provided by a NFS/NAS server. Running VMs directly from shared storage can enhance the fault tolerance of the system in the event of a host failure, although it comes with the drawback of increased I/O latency.

Note

The playbook assumes that you have already a working NFS server available in your cloud.

Storage

NFS server configuration

The NFS/NAS server is configured to export the datastore folders to the hosts in the OpenNebula cloud. In this example we assume that the following structure is created in the NFS/NAS sever:

root@nfs-server:/# ls -ln /storage
total 0
drwxr-xr-x 2 9869 9869 6 Jun 26 17:55 one_datastores

Important

The ownership of the folders MUST be 9869 as this is the UID/GID assigned to the oneadmin account during the installation.

This folder is exported to the OpenNebula servers, for example:

# /etc/exports
#
# See exports(5) for more information.
#
# Use exportfs -r to reread
# /export	192.168.1.10(rw,no_root_squash)
/storage/one_datastores 172.20.0.0/24(rw,soft,intr,async)

Inventory

The following snippet shows the configuration required to use the shared storage using the above NFS share (assuming the NFS server is at 172.20.0.1):

    ds: { mode: shared }

    fstab:
      - src: "172.20.0.1:/storage/one_datastores"

By default the share is mounted in /var/lib/one/datastores/, but this behavior can be changed so any type of /etc/fstab entry should be possible to configure, see additional examples below.

Networking

To configure the network you can follow the local storage scenario section.

OpenNebula Front-end & Services

To configure the front-end services or using your enterprise edition token you can follow the local storage scenario sections.

The complete inventory file

The following file show the complete settings to install a single front-end with two hosts using shared storage:

---
all:
  vars:
    ansible_user: root
    one_version: '6.10'
    one_pass: opennebulapass

    vn:
      service:
        managed: true
        template:
          VN_MAD: bridge
          BRIDGE: br0
          AR:
            TYPE: IP4
            IP: 172.20.0.100
            SIZE: 48
          NETWORK_ADDRESS: 172.20.0.0
          NETWORK_MASK: 255.255.255.0
          GATEWAY: 172.20.0.1
          DNS: 1.1.1.1

    ds: { mode: shared }

    fstab:
      - src: "172.20.0.1:/storage/one_datastores"

frontend:
  hosts:
    f1: { ansible_host: 172.20.0.6 }

node:
  hosts:
    n1: { ansible_host: 172.20.0.7 }
    n2: { ansible_host: 172.20.0.8 }

Running the Ansible Playbook

  • 1. Prepare the inventory file: Update the shared.yml file in the inventory file to match your infrastructure settings. Please be sure to update or review the following variables:

    • ansible_user, update it if different from root.
    • one_pass, change it to the password for the oneadmin account
    • one_version, be sure to use the latest stable version here

  • 2. Check the connection: Verify the network connection, ssh and sudo configuration run the following command:

ansible -i inventory/shared.yml all -m ping -b
  • 3. Site installation: Now we can run the site playbook that install and configure OpenNebula services
ansible-playbook -i inventory/shared.yml opennebula.deploy.main

Once the execution of the playbook finish your new OpenNebula cloud is ready. You can now head to the verification guide.

Additional NFS Configuration Options

Playbooks support the setup of any type of fstab entry, and includes helpers to automatically link NFS folders to datastore folders. For example, you can use multiple NFS servers for different datastores:

    ds:
      mode: shared
      config:
        mounts:
          - type: system
            path: /mnt_nfs1/0
          - type: image
            path: /mnt_nfs2/1
          - type: file
            path: /mnt_nfs1/2

    fstab:
      - src: "10.2.50.1:/shared_one"
        path: /mnt_nfs1
        fstype: nfs
        opts: rw,soft,intr,rsize=32768,wsize=32768

      - src: "10.2.50.33:/shared_one"
        path: /mnt_nfs2
        fstype: nfs
        opts: rw,soft,intr,rsize=32768,wsize=32768

After running the playbook you will see the following set up in the hosts:

root@ubuntu2204-18:~# ls -l /var/lib/one/datastores/
total 0
lrwxrwxrwx 1 root root 7 Jun 27 11:10 0 -> /mnt_nfs1/0/
lrwxrwxrwx 1 root root 7 Jun 27 11:10 1 -> /mnt_nfs2/1/

Note

File (/mnt/nfs_1/2) will only be symlinked in the front-end

It's also perfectly viable to define different fstab lists for each distinct inventory hostname, group or subgroup as well:

frontend:
  vars:
    fstab:
      - src: "10.2.50.1:/var/lib/one/datastores"
  hosts:
    n1a1: { ansible_host: 10.2.50.10 }
    n1a2: { ansible_host: 10.2.50.11 }

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