MNAIO: Enable using a data disk for file-backed VM's

In order to make use of a data disk, we enable the 'file' implementation of default_vm_disk_mode to use a data disk much like the 'lvm' implementation. To simplify changing from the default_vm_disk_mode of lvm to file and back again, the setup-host playbook will remove any previous implementation and replace it. This is useful when doing testing for these different modes because it does not require cleaning up by hand. This patch also fixes the implementation of the virt storage pool. Currently the tasks only execute if 'virt_data_volume.pools is not defined', but it is always defined so the tasks never execute. We now ensure that for both backing stores the 'default' storage pool is defined, started and set to auto start (as three tasks because the virt_pool module sucks really bad and can only do one thing at a time). The pool implementation for the 'file' backed VM's uses the largest data disk it can find and creates the /data mount for it. To cater for a different configuration, we ensure that all references to the disk files use the path that is configured in the pool ,rather than assuming the path. Change-Id: If7e7e37df4d7c0ebe9d003e5b5b97811d41eff22
2018-08-15 14:18:28 +01:00 · 2018-08-15 14:18:28 +01:00 · 484059205a
commit 484059205a
parent 8b508a9d90
5 changed files with 150 additions and 64 deletions
--- a/multi-node-aio/README.rst
+++ b/multi-node-aio/README.rst
@ -263,9 +263,9 @@ backing store) for the VM's, then set the following option before executing

 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 save the files to
-``/var/lib/libvirt/images/*-base.img``. Re-executing the ``deploy-vms.yml``
-playbook afterwards will rebuild the VMs from those images.
+``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

--- a/multi-node-aio/playbooks/deploy-vms.yml
+++ b/multi-node-aio/playbooks/deploy-vms.yml
@ -31,6 +31,11 @@
      tags:
        - always

+    - name: Get info about the virt storage pools
+      virt_pool:
+        command: info
+      register: _virt_pools
+
    - name: Stop running VMs
      virt:
        name: "{{ hostvars[item]['server_hostname'] }}"
@ -53,7 +58,7 @@

    - name: Delete VM Disk Image
      file:
-        path: "/var/lib/libvirt/images/{{ hostvars[item]['server_hostname'] }}.img"
+        path: "{{ _virt_pools.pools.default.path | default('/data') }}/{{ hostvars[item]['server_hostname'] }}.img"
        state: absent
      when:
        - hostvars[item]['server_vm'] | default(false) | bool
@ -84,7 +89,7 @@
      block:
        - name: Find existing base image files
          find:
-            paths: /var/lib/libvirt/images
+            paths: "{{ _virt_pools.pools.default.path | default('/data') }}"
            patterns: '*-base.img'
          register: _base_images

@ -99,9 +104,9 @@
            qemu-img create
            -f qcow2
            {% if vm_use_snapshot | bool %}
-            -b /var/lib/libvirt/images/{{ hostvars[item]['server_hostname'] }}-base.img
+            -b {{ _virt_pools.pools.default.path | default('/data') }}/{{ hostvars[item]['server_hostname'] }}-base.img
            {% endif %}
-            /var/lib/libvirt/images/{{ hostvars[item]['server_hostname'] }}.img
+            {{ _virt_pools.pools.default.path | default('/data') }}/{{ hostvars[item]['server_hostname'] }}.img
            {{ default_vm_storage }}m
          when:
            - hostvars[item]['server_vm'] | default(false) | bool
--- a/multi-node-aio/playbooks/kvm/kvm-vm.xml.j2
+++ b/multi-node-aio/playbooks/kvm/kvm-vm.xml.j2
@ -41,7 +41,7 @@
 {% elif default_vm_disk_mode == "file" %}
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2' cache='none' io='native'/>
-      <source file='/var/lib/libvirt/images/{{ hostvars[item]["server_hostname"] }}.img'/>
+      <source file='{{ _virt_pools.pools.default.path | default('/data') }}/{{ hostvars[item]["server_hostname"] }}.img'/>
 {% endif %}
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
--- a/multi-node-aio/playbooks/save-vms.yml
+++ b/multi-node-aio/playbooks/save-vms.yml
@ -31,6 +31,11 @@
      tags:
        - always

+    - name: Get info about the virt storage pools
+      virt_pool:
+        command: info
+      register: _virt_pools
+
    - name: Stop running VMs
      command: "virsh destroy {{ hostvars[item]['server_hostname'] }}"
      failed_when: false
@ -41,8 +46,8 @@
    - name: Save VM Disk Image
      command: >-
        mv
-        /var/lib/libvirt/images/{{ hostvars[item]['server_hostname'] }}.img
-        /var/lib/libvirt/images/{{ hostvars[item]['server_hostname'] }}-base.img
+        {{ _virt_pools.pools.default.path | default('/data') }}/{{ hostvars[item]['server_hostname'] }}.img
+        {{ _virt_pools.pools.default.path | default('/data') }}/{{ hostvars[item]['server_hostname'] }}-base.img
      when:
        - hostvars[item]['server_vm'] | default(false) | bool
      with_items: "{{ groups['pxe_servers'] }}"
--- a/multi-node-aio/playbooks/setup-host.yml
+++ b/multi-node-aio/playbooks/setup-host.yml
@ -242,77 +242,153 @@
      with_dict: "{{ mnaio_host_networks }}"
      when: "item.value.iface not in vm_networks.list_nets"

-    - name: Locate data volume
-      command: "vgdisplay vg01"
-      failed_when: false
+    - name: Locate the largest writable data disk if mnaio_data_disk is not set
+      shell: >
+        lsblk -brndo NAME,TYPE,FSTYPE,RO,SIZE | awk '/d[b-z]+ disk +0/{ if ($4>m){m=$4; d=$1}}; END{print d}'
+      register: lsblk
+      changed_when: false
      when:
-        - default_vm_disk_mode == "lvm"
-      register: data_volume
+        - mnaio_data_disk is undefined

-    - name: Setup the data volume (LVM)
+    - 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:
-        - default_vm_disk_mode == "lvm"
-        - data_volume.rc != 0
+        - _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: Locate data disk
-          shell: >
-            lsblk -brndo NAME,TYPE,FSTYPE,RO,SIZE | awk '/d[b-z]+ disk +0/{ if ($4>m){m=$4; d=$1}}; END{print d}'
-          register: lsblk
+        - name: Dismount the mount point if default_vm_disk_mode is 'lvm'
+          mount:
+            path: /data
+            state: unmounted
          when:
-            - mnaio_data_disk is undefined
+            - default_vm_disk_mode == "lvm"

-        - name: Create data disk label
-          command: "parted --script /dev/{{ mnaio_data_disk | default(lsblk.stdout) }} mklabel gpt"
+        - name: Stop the pool
+          virt_pool:
+            command: destroy
+            name: default

-        - name: Create data disk partition
-          command: "parted --align optimal --script /dev/{{ mnaio_data_disk | default(lsblk.stdout) }} mkpart data1 ext4 0% 100%"
+        - name: Delete the pool, destroying its contents
+          virt_pool:
+            command: delete
+            name: default

-        - name: Create data volume group
+        - 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) }}"
+        label: gpt
+        number: 1
+        name: data1
+        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: Locate virt data volume
-      virt_pool:
-        name: "vg01"
-        command: info
-      failed_when: false
+        - 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 == "lvm"
-      register: virt_data_volume
-
-    - name: Create /etc/libvirt/storage directory
-      file:
-        path: "/etc/libvirt/storage/"
-        state: "directory"
-
-    - name: Create virt data volume
+        - default_vm_disk_mode == "file"
      block:
-        - name: Create virt pool
-          virt_pool:
-            command: create
-            name: vg01
+        - name: Prepare the data disk file system
+          filesystem:
+            fstype: ext4
+            dev: "/dev/{{ mnaio_data_disk | default(lsblk.stdout) }}1"
+            force: yes
+          when:
+            - _add_partition is changed

-        - name: Get virt pool xml
-          virt_pool:
-            command: get_xml
-            name: vg01
-          register: virt_pool_xml
+        - name: Mount the data disk
+          mount:
+            src: "/dev/{{ mnaio_data_disk | default(lsblk.stdout) }}1"
+            path: /data
+            state: mounted
+            fstype: ext4

-        - name: Write data volume xml
-          copy:
-            content: "{{ virt_pool_xml.get_xml }}"
-            dest: "/etc/libvirt/storage/vg01.xml"
-
-        - name: Define virt data volume
+        - name: Define the default virt storage pool
          virt_pool:
-            command: define
-            name: vg01
-            xml: "/etc/libvirt/storage/vg01.xml"
-            autostart: true
-      when:
-        - default_vm_disk_mode == "lvm"
-        - virt_data_volume.pools is not defined
+            name: default
+            state: present
+            xml: |
+              <pool type='dir'>
+                <name>default</name>
+                <target>
+                  <path>/data</path>
+                  <permissions>
+                    <mode>0755</mode>
+                    <owner>0</owner>
+                    <group>0</group>
+                  </permissions>
+                </target>
+              </pool>
+
+    - name: Set default virt storage pool to active
+      virt_pool:
+        name: default
+        state: active
+
+    - name: Set default virt storage pool to autostart
+      virt_pool:
+        name: default
+        autostart: yes

    - name: Load virtio kernel modules
      shell: |