arch_single_shared

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 configured and mounted the NFS shares in all the servers.

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 /srv
total 0
drwxr-xr-x 2 9869 9869 6 Jun 26 17:55 0
drwxr-xr-x 2 9869 9869 6 Jun 26 17:55 1
drwxr-xr-x 2 9869 9869 6 Jun 26 17:55 2

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

:important: Note: The files & kernels datastore (folder /srv/2, in the example) will be only mounted in the front-end; hosts will always use local storage for this datastore.

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)
/srv 172.20.0.0/24(rw,soft,intr,async)

After running the playbook you will see the following set up in the front-end:

root@ubuntu2204-17:~# ls -l /var/lib/one/datastores/
total 4
lrwxrwxrwx 1 root     root        7 Jun 27 11:12 1 -> /mnt/1/
drwxr-xr-x 2 oneadmin oneadmin 4096 Jun 27 11:09 2

NFS client configuration

In this example all servers (front-end and hosts) mounts the NFS shared under the /mnt folder:

root@ubuntu2204-17:/# ls -la /mnt/
total 4
drwxr-xr-x  5 root root   33 Jun 26 15:58 .
drwxr-xr-x 18 root root 4096 Jun 27 09:30 ..
drwxr-xr-x  2 9869 9869    6 Jun 26 15:55 0
drwxr-xr-x  2 9869 9869    6 Jun 26 15:55 1
drwxr-xr-x  2 9869 9869    6 Jun 26 15:55 2

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/0/
lrwxrwxrwx 1 root root 7 Jun 27 11:10 1 -> /mnt/1/

Inventory

The following snippet shows the configuration required to use the shared storage using the above mount points:

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

Note

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

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: '6.6'
    one_pass: opennebulapass
    ds:
      mode: shared
      config:
        mounts:
        - type: system
          path: /mnt/0
        - type: image
          path: /mnt/1
        - type: file
          path: /mnt/2
    vn:
      admin_net:
        managed: true
        template:
          VN_MAD: bridge
          PHYDEV: eth0
          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

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.