MNAIO: Switch to using file-backed VM's only

The MNAIO tooling is a test system, and with that target
we can afford to be opinionated in the implementation
rather than try to cater to every possibility.

Now that the file-backed VM implementation has matured,
we can switch to using it exclusively. This cuts down on
code complexity and allows us to mature the implementation
further with more options without having to cater to two
options.

Change-Id: Ibe04b5676a392301cd79a5d290b77df4c7d9f79a

multi-node-aio/README.rst

@@ -114,7 +114,6 @@ Set to instruct the preseed what the default network is expected to be:
 Set the VM disk size in gigabytes:
   ``VM_DISK_SIZE="${VM_DISK_SIZE:-252}"``
 
-
 Instruct the system do all of the required host setup:
   ``SETUP_HOST=${SETUP_HOST:-true}``
 
@@ -203,20 +202,9 @@ Instruct the system to use a customized iPXE script during boot of VMs:
 Re-kicking VM(s)
 ----------------
 
-Re-kicking a VM is as simple as stopping a VM, delete the logical volume, create
+To re-kick all VMs, simply re-execute the ``deploy-vms.yml`` playbook and it
-a new logical volume, start the VM. The VM will come back online, pxe boot, and
+will do it automatically. The ansible ``--limit`` parameter may be used to
-install the base OS.
+selectively re-kick a specific VM.
-
-.. code-block:: bash
-
-    virsh destroy "${VM_NAME}"
-    lvremove "/dev/mapper/vg01--${VM_NAME}"
-    lvcreate -L 60G vg01 -n "${VM_NAME}"
-    virsh start "${VM_NAME}"
-
-
-To rekick all VMs, simply re-execute the ``deploy-vms.yml`` playbook and it will
-do it automatically.
 
 .. code-block:: bash
 
@@ -267,47 +255,37 @@ command or the following bash loop to restore everything to a known point.
       virsh snapshot-revert --snapshotname $instance-kilo-snap --running $instance
     done
 
-Using a file-based backing store with thin-provisioned VM's
+Saving VM images for re-use on another host
------------------------------------------------------------
+-------------------------------------------
 
-If you wish to use a file-based backing store (instead of the default LVM-based
+If you wish to save the current images in order to implement a thin-provisioned
-backing store) for the VM's, then set the following option before executing
+set of VM's which can be saved and re-used, then use the ``save-vms.yml``
-``build.sh``.
+playbook. This will stop the VM's and rename the files to ``*-base.img``.
-
+Re-executing the ``deploy-vms.yml`` playbook afterwards will rebuild the VMs
-.. code-block:: bash
+from those images.
-
-    export MNAIO_ANSIBLE_PARAMETERS="-e default_vm_disk_mode=file"
-    ./build.sh
-
-If you wish to save the current file-based images in order to implement a
-thin-provisioned set of VM's which can be saved and re-used, then use the
-``save-vms.yml`` playbook. This will stop the VM's and rename the files to
-``*-base.img``. Re-executing the ``deploy-vms.yml`` playbook afterwards will
-rebuild the VMs from those images.
 
 .. code-block:: bash
 
     ansible-playbook -i playbooks/inventory playbooks/save-vms.yml
-    ansible-playbook -i playbooks/inventory -e default_vm_disk_mode=file playbooks/deploy-vms.yml
+    ansible-playbook -i playbooks/inventory playbooks/deploy-vms.yml
 
 To disable this default functionality when re-running ``build.sh`` set the
-build not to use the snapshots as follows.
+build not to use the images as follows.
 
 .. code-block:: bash
 
-    export MNAIO_ANSIBLE_PARAMETERS="-e default_vm_disk_mode=file -e vm_use_snapshot=no"
+    export MNAIO_ANSIBLE_PARAMETERS="-e vm_use_snapshot=no"
     ./build.sh
 
-If you have previously saved some file-backed images to remote storage then,
+If you have previously saved some images to remote storage then, if they are
-if they are available via a URL, they can be downloaded and used on a fresh
+available via a URL, they can be downloaded and used on a fresh host as follows.
-host as follows.
 
 .. code-block:: bash
 
     # First prepare the host and get the base services started
     ./bootstrap.sh
     source ansible-env.rc
-    export ANSIBLE_PARAMETERS="-i playbooks/inventory -e default_vm_disk_mode=file"
+    export ANSIBLE_PARAMETERS="-i playbooks/inventory"
     ansible-playbook ${ANSIBLE_PARAMETERS} playbooks/setup-host.yml
     ansible-playbook ${ANSIBLE_PARAMETERS} playbooks/deploy-acng.yml playbooks/deploy-pxe.yml playbooks/deploy-dhcp.yml
 

multi-node-aio/playbooks/deploy-vms.yml

@@ -41,15 +41,6 @@
       failed_when: false
       with_items: "{{ _virt_list.list_vms }}"
 
-    - name: Delete any LV's related to running VM's
-      lvol:
-        vg: "{{ default_vm_disk_vg }}"
-        lv: "{{ item }}"
-        state: absent
-        force: yes
-      failed_when: false
-      with_items: "{{ _virt_list.list_vms }}"
-
     - name: Delete any disk images related to running VM's
       file:
         path: "{{ _virt_pools.pools.default.path | default('/data/images') }}/{{ item }}.img"
@@ -63,10 +54,6 @@
       failed_when: false
       with_items: "{{ _virt_list.list_vms }}"
 
-    - name: Setup/clean-up file-based disk images
-      when:
-        - default_vm_disk_mode == "file"
-      block:
     - name: Find existing base image files
       find:
         paths: "{{ _virt_pools.pools.default.path | default('/data/images') }}"
@@ -93,17 +80,6 @@
   tags:
     - deploy-vms
   tasks:
-    - name: Create VM LV
-      lvol:
-        vg: "{{ default_vm_disk_vg }}"
-        lv: "{{ server_hostname }}"
-        size: "{{ default_vm_storage }}"
-      when:
-        - server_vm | default(false) | bool
-        - default_vm_disk_mode == "lvm"
-      delegate_to: "{{ item }}"
-      with_items: "{{ groups['vm_hosts'] }}"
-
     - name: Create VM Disk Image
       command: >-
         qemu-img create
@@ -115,7 +91,6 @@
         {{ default_vm_storage }}m
       when:
         - server_vm | default(false) | bool
-        - default_vm_disk_mode == "file"
       delegate_to: "{{ item }}"
       with_items: "{{ groups['vm_hosts'] }}"
 
@@ -134,7 +109,6 @@
     # ref: https://bugs.launchpad.net/ubuntu/+source/libguestfs/+bug/1615337.
     - name: Prepare file-based disk images
       when:
-        - default_vm_disk_mode == "file"
         - vm_use_snapshot | bool
       block:
         - name: Inject the host ssh key into the VM disk image

multi-node-aio/playbooks/group_vars/all.yml

@@ -15,8 +15,6 @@ default_interface: "{{ default_network | default('eth0') }}"
 default_vm_image: "{{ default_image | default('ubuntu-16.04-amd64') }}"
 default_vm_storage: "{{ vm_disk_size | default(92160) }}"
 default_vm_root_disk_size: 8192
-default_vm_disk_mode: lvm
-default_vm_disk_vg: vg01
 default_acng_bind_address: 0.0.0.0
 default_os_families:
   ubuntu-16.04-amd64: debian
@@ -37,7 +35,7 @@ ipxe_kernel_base_url: "http://boot.ipxe.org"
 vm_ssh_timeout: 1500
 
 # Whether to use snapshots (if they are available) for file-backed VM's
-vm_use_snapshot: "{{ default_vm_disk_mode == 'file' }}"
+vm_use_snapshot: yes
 
 # IP address, or domain name of the TFTP server
 tftp_server: "{{ hostvars[groups['pxe_hosts'][0]]['ansible_host'] | default(ansible_host) }}"

multi-node-aio/playbooks/kvm/kvm-vm.xml.j2

@@ -34,15 +34,9 @@
   </pm>
   <devices>
     <emulator>/usr/bin/kvm-spice</emulator>
-{% if default_vm_disk_mode == "lvm" %}
-    <disk type='block' device='disk'>
-      <driver name='qemu' type='raw' cache='none' io='native'/>
-      <source dev='/dev/{{ default_vm_disk_vg }}/{{ server_hostname }}'/>
-{% elif default_vm_disk_mode == "file" %}
     <disk type='file' device='disk'>
       <driver name='qemu' type='qcow2' discard='unmap' cache='none' io='native'/>
       <source file='{{ hostvars[item]['virt_pools'].pools.default.path | default('/data/images') }}/{{ server_hostname }}.img'/>
-{% endif %}
       <target dev='sda' bus='scsi'/>
       <alias name='scsi0-0-0-0'/>
       <address type='drive' controller='0' bus='0' target='0' unit='0'/>

multi-node-aio/playbooks/setup-host.yml

@@ -326,95 +326,6 @@
       when:
         - mnaio_data_disk is undefined
 
-    - name: Get info about existing virt storage pools
-      virt_pool:
-        command: info
-      register: _virt_pools
-
-    - name: If an existing virt pool does not match default_vm_disk_mode, remove it
-      when:
-        - _virt_pools.pools.default is defined
-        - (default_vm_disk_mode == "file" and _virt_pools.pools.default.format is defined) or
-          (default_vm_disk_mode == "lvm" and _virt_pools.pools.default.format is not defined)
-      block:
-        - name: Stop running VMs
-          virt:
-            name: "{{ item }}"
-            command: destroy
-          failed_when: false
-          with_items: "{{ _virt_pools.pools.default.volumes }}"
-
-        - name: Delete VM LVs
-          lvol:
-            vg: "{{ default_vm_disk_vg }}"
-            lv: "{{ item }}"
-            state: absent
-            force: yes
-          failed_when: false
-          with_items: "{{ _virt_pools.pools.default.volumes }}"
-
-        - name: Delete VM Disk Images
-          file:
-            path: "{{ _virt_pools.pools.default.path | default('/data/images') }}/{{ item }}.img"
-            state: absent
-          with_items: "{{ _virt_pools.pools.default.volumes }}"
-
-        - name: Undefine the VMs
-          virt:
-            name: "{{ item }}"
-            command: undefine
-          failed_when: false
-          with_items: "{{ _virt_pools.pools.default.volumes }}"
-
-        - name: Dismount the mount point if default_vm_disk_mode is 'lvm'
-          mount:
-            path: /data
-            state: unmounted
-          when:
-            - default_vm_disk_mode == "lvm"
-
-        - name: Stop the pool
-          virt_pool:
-            command: destroy
-            name: default
-
-        - name: Delete the pool, destroying its contents
-          virt_pool:
-            command: delete
-            name: default
-
-        - name: Undefine the pool
-          virt_pool:
-            command: undefine
-            name: default
-
-        - name: Remove the mount point if default_vm_disk_mode is 'lvm'
-          mount:
-            path: /data
-            state: absent
-          when:
-            - default_vm_disk_mode == "lvm"
-
-        - name: Reload systemd to remove generated unit files for mount
-          systemd:
-            daemon_reload: yes
-          when:
-            - default_vm_disk_mode == "lvm"
-
-        - name: Remove the volume group if default_vm_disk_mode is 'file'
-          lvg:
-            vg: vg01
-            state: absent
-          register: _remove_vg
-          when:
-            - default_vm_disk_mode == "file"
-
-        - name: Remove the existing disk partition
-          parted:
-            device: "/dev/{{ mnaio_data_disk | default(lsblk.stdout) }}"
-            number: 1
-            state: absent
-
     - name: Setup the data disk partition
       parted:
         device: "/dev/{{ mnaio_data_disk | default(lsblk.stdout) }}"
@@ -424,35 +335,6 @@
         state: present
       register: _add_partition
 
-    - name: Prepare the data disk for 'lvm' default_vm_disk_mode
-      when:
-        - default_vm_disk_mode == "lvm"
-      block:
-        - name: Create the volume group
-          lvg:
-            vg: vg01
-            pvs: "/dev/{{ mnaio_data_disk | default(lsblk.stdout) }}1"
-
-        - name: Define the default virt storage pool
-          virt_pool:
-            name: default
-            state: present
-            xml: |
-              <pool type='logical'>
-                <name>default</name>
-                <source>
-                  <name>vg01</name>
-                  <format type='lvm2'/>
-                </source>
-                <target>
-                  <path>/dev/vg01</path>
-                </target>
-              </pool>
-
-    - name: Prepare the data disk for 'file' default_vm_disk_mode
-      when:
-        - default_vm_disk_mode == "file"
-      block:
     - name: Prepare the data disk file system
       filesystem:
         fstype: ext4