lvg

#!/usr/bin/python
# -*- coding: utf-8 -*-

# (c) 2013, Alexander Bulimov <lazywolf0@gmail.com>
# based on lvol module by Jeroen Hoekx <jeroen.hoekx@dsquare.be>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.

DOCUMENTATION = '''
---
author: Alexander Bulimov
module: lvg
short_description: Configure LVM volume groups
description:
  - This module creates, removes or resizes volume groups.
version_added: "1.1"
options:
  vg:
    description:
    - The name of the volume group.
    required: true
  pvs:
    description:
    - List of comma-separated devices to use as physical devices in this volume group. Required when creating or resizing volume group.
    required: false
  pesize:
    description:
    - The size of the physical extent in megabytes. Must be a power of 2.
    default: 4
    required: false
  state:
    choices: [ "present", "absent" ]
    default: present
    description:
    - Control if the volume group exists.
    required: false
  force:
    choices: [ "yes", "no" ]
    default: "no"
    description:
    - If yes, allows to remove volume group with logical volumes.
    required: false
examples:
  - description: Create a volume group on top of /dev/sda1 with physical extent size = 32MB.
    code: lvg vg=vg.services pvs=/dev/sda1 pesize=32
  - description: Create or resize a volume group on top of /dev/sdb1 and /dev/sdc5. 
        If, for example, we already have VG vg.services on top of /dev/sdb1, this VG will be extended by /dev/sdc5.
        Or if vg.services was created on top of /dev/sda5, we first extend it with /dev/sdb1 and /dev/sdc5, and then reduce by /dev/sda5.
    code: lvg vg=vg.services pvs=/dev/sdb1,/dev/sdc5
  - description: Remove a volume group with name vg.services.
    code: lvg vg=vg.services state=absent
notes:
  - module does not modify PE size for already present volume group
'''

def parse_vgs(data):
    vgs = []
    for line in data.splitlines():
        parts = line.strip().split(';')
        vgs.append({
            'name': parts[0],
            'pv_count': int(parts[1]),
            'lv_count': int(parts[2]),
        })
    return vgs

def parse_pvs(data):
    pvs = []
    for line in data.splitlines():
        parts = line.strip().split(';')
        pvs.append({
            'name': parts[0],
            'vg_name': parts[1],
        })
    return pvs

def main():
    module = AnsibleModule(
        argument_spec = dict(
            vg=dict(required=True),
            pvs=dict(type='list'),
            pesize=dict(type='int', default=4),
            state=dict(choices=["absent", "present"], default='present'),
            force=dict(type='bool', default='no'),
        ),
        supports_check_mode=True,
    )

    vg = module.params['vg']
    state = module.params['state']
    force = module.boolean(module.params['force'])
    pesize = module.params['pesize']

    if module.params['pvs']:
        dev_string = ' '.join(module.params['pvs'])
        dev_list = module.params['pvs']
    elif state == 'present':
        module.fail_json(msg="No physical volumes given.")

    if state=='present':
        ### check given devices
        for test_dev in dev_list:
            if not os.path.exists(test_dev):
                module.fail_json(msg="Device %s not found."%test_dev)

        ### get pv list
        rc,current_pvs,err = module.run_command("pvs --noheadings -o pv_name,vg_name --separator ';'")
        if rc != 0:
            module.fail_json(msg="Failed executing pvs command.",rc=rc, err=err)

        ### check pv for devices
        pvs = parse_pvs(current_pvs)
        used_pvs = [ pv for pv in pvs if pv['name'] in dev_list and pv['vg_name'] and pv['vg_name'] != vg ]
        if used_pvs:
            module.fail_json(msg="Device %s is already in %s volume group."%(used_pvs[0]['name'],used_pvs[0]['vg_name']))

    rc,current_vgs,err = module.run_command("vgs --noheadings -o vg_name,pv_count,lv_count --separator ';'")

    if rc != 0:
        module.fail_json(msg="Failed executing vgs command.",rc=rc, err=err)

    changed = False

    vgs = parse_vgs(current_vgs)

    for test_vg in vgs:
        if test_vg['name'] == vg:
            this_vg = test_vg
            break
    else:
        this_vg = None

    if this_vg is None:
        if state == 'present':
            ### create VG
            if module.check_mode:
                changed = True
            else:
                ### create PV
                for current_dev in dev_list:
                    rc,_,err = module.run_command("pvcreate %s"%current_dev)
                    if rc == 0:
                        changed = True
                    else:
                        module.fail_json(msg="Creating physical volume '%s' failed"%current_dev, rc=rc, err=err)
                rc,_,err = module.run_command("vgcreate -s %s %s %s"%(pesize, vg, dev_string))
                if rc == 0:
                    changed = True
                else:
                    module.fail_json(msg="Creating volume group '%s' failed"%vg, rc=rc, err=err)
    else:
        if state == 'absent':
            if module.check_mode:
                module.exit_json(changed=True)
            else:
                if this_vg['lv_count'] == 0 or force:
                    ### remove VG
                    rc,_,err = module.run_command("vgremove --force %s"%(vg))
                    if rc == 0:
                        module.exit_json(changed=True)
                    else:
                        module.fail_json(msg="Failed to remove volume group %s"%(vg),rc=rc, err=err)
                else:
                    module.fail_json(msg="Refuse to remove non-empty volume group %s without force=yes"%(vg))

        ### resize VG
        current_devs = [ pv['name'] for pv in pvs if pv['vg_name'] == vg ]
        devs_to_remove = list(set(current_devs) - set(dev_list))
        devs_to_add = list(set(dev_list) - set(current_devs))

        if devs_to_add or devs_to_remove:
            if module.check_mode:
                changed = True
            else:
                if devs_to_add:
                    devs_to_add_string = ' '.join(devs_to_add)
                    ### create PV
                    for current_dev in devs_to_add:
                        rc,_,err = module.run_command("pvcreate %s"%current_dev)
                        if rc == 0:
                            changed = True
                        else:
                            module.fail_json(msg="Creating physical volume '%s' failed"%current_dev, rc=rc, err=err)
                    ### add PV to our VG
                    rc,_,err = module.run_command("vgextend %s %s"%(vg, devs_to_add_string))
                    if rc == 0:
                        changed = True
                    else:
                        module.fail_json(msg="Unable to extend %s by %s."%(vg, devs_to_add_string),rc=rc,err=err)

                ### remove some PV from our VG
                if devs_to_remove:
                    devs_to_remove_string = ' '.join(devs_to_remove)
                    rc,_,err = module.run_command("vgreduce --force %s %s"%(vg, devs_to_remove_string))
                    if rc == 0:
                        changed = True
                    else:
                        module.fail_json(msg="Unable to reduce %s by %s."%(vg, devs_to_remove_string),rc=rc,err=err)

    module.exit_json(changed=changed)

# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()