LVM Configuration using Ansible in CentOS 7

1. Install epel repo on CentOS 7 system:

  # yum install epel-release -y

2. Install ansible using yum:

  # yum install ansible -y  

3. Open '/etc/ansible/hosts' file and make a group called 'dbhosts' to add two hosts in it:

  # vi  /etc/ansible/hosts

  [dbhosts]
   host1.example.com
   host2.example.com

 4. Configure passwordless ssh to both host1 & host2 from ansible server:

  # ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
ce:7d:fd:65:4e:61:4e:a9:09:61:90:d2:75:1b:d1:1d root@server.example.com
The key's randomart image is:

+--[ RSA 2048]----+

|        ..o. +oEo|

|       . o. . o..|

|        .  o .   |

|          . .   .|

|        S  .   = |

|       o .  ..* .|

|        o . .o..+|

|           .   =.|

|                o|

+-----------------+

5. Copy the public key to both the hosts one by one using below command:

  # ssh-copy-id -i /root/.ssh/id_rsa.pub root@hots1.example.com
  # ssh-copy-id -i /root/.ssh/id_rsa.pub root@host2.example.com

6. Validate if ansible server is able to communicate with client systems or not:

    # ansible dbhosts -m ping
    host1.example.com | SUCCESS => {
        "changed": false,
        "ping": "pong"
    }
    host2.example.com | SUCCESS => {
        "changed": false,
        "ping": "pong"
    }

7. Create an ansible playbook with 'lvmvol.yaml' name to perform the below tasks:

• It will considered that a 20GB disk is attached to the system and detected as '/dev/sdb'. 
• This will make 4 partitions of 2GB each and mount them into /db00, /db01, /db02 & /db03 respectively.
• The name of the vg will be 'dbvg' and lvm will be db00, db01, db02 & db03.
• Finally it will make a fstab entry to mount them across system reboot.

  # vim lvmvol.yaml
---
 - hosts: dbhosts
   user: root
   tasks:
        - name: dbvg volume group creation
          lvg:
               vg: dbvg
               pvs: /dev/sdb

        - name: db00 lvm creation
          lvol:
               vg: dbvg
               lv: db00
               size: 2G

        - name: db01 lvm creation
          lvol:
               vg: dbvg
               lv: db01
               size: 2G

        - name: db02 lvm creation
          lvol:
               vg: dbvg
               lv: db02
               size: 2G

        - name: db03 lvm creation
          lvol:
               vg: dbvg
               lv: db03
               size: 2G

        - name: create file system for db00
          filesystem:
                fstype: ext4
                dev: /dev/dbvg/db00

        - name: create file system for db01
          filesystem:
                fstype: ext4
                dev: /dev/dbvg/db01

        - name: create file system for db02
          filesystem:
                fstype: ext4
                dev: /dev/dbvg/db02

        - name: create file system for db03
          filesystem:
                fstype: ext4
                dev: /dev/dbvg/db03

        - name: mount db00 logical volumes
          mount:
                name: /db00
                src: /dev/dbvg/db00
                fstype: ext4
                state: mounted

        - name: mount db01 logical volumes
          mount:
                name: /db01
                src: /dev/dbvg/db01
                fstype: ext4
                state: mounted

        - name: mount db02 logical volumes
          mount:
                name: /db02
                src: /dev/dbvg/db02
                fstype: ext4
                state: mounted

        - name: mount db03 logical volumes
          mount:
                name: /db03
                src: /dev/dbvg/db03
                fstype: ext4
                state: mounted

8. Run the ansible playbook using the below command:

    # ansible-playbook lvmvol.yaml

PLAY [dbhosts] *********************************************************************************

TASK [Gathering Facts] *********************************************************************************
ok: [host2.example.com]
ok: [host1.example.com]

TASK [dbvg volume group creation] *********************************************************************************
changed: [host2.example.com]
changed: [host1.example.com]

TASK [db00 lvm creation] *********************************************************************************
changed: [host2.example.com]
changed: [host1.example.com]

TASK [db01 lvm creation] *********************************************************************************
changed: [host2.example.com]
changed: [host1.example.com]

TASK [db02 lvm creation] *********************************************************************************
changed: [host2.example.com]
changed: [host1.example.com]

TASK [db03 lvm creation] *********************************************************************************
changed: [host2.example.com]
changed: [host1.example.com]

TASK [create file system for db00] *********************************************************************************
changed: [host2.example.com]
changed: [host1.example.com]

TASK [create file system for db01] *********************************************************************************
changed: [host2.example.com]
changed: [host1.example.com]

TASK [create file system for db02] *********************************************************************************
changed: [host2.example.com]
changed: [host1.example.com]

TASK [create file system for db03] *********************************************************************************
changed: [host2.example.com]
changed: [host1.example.com]

TASK [mount db00 logical volumes] *********************************************************************************
changed: [host2.example.com]
changed: [host1.example.com]

TASK [mount db01 logical volumes] *********************************************************************************
changed: [host1.example.com]
changed: [host2.example.com]

TASK [mount db02 logical volumes] *********************************************************************************
changed: [host1.example.com]
changed: [host2.example.com]

TASK [mount db03 logical volumes] *********************************************************************************
changed: [host1.example.com]
changed: [host2.example.com]

PLAY RECAP *********************************************************************************
host1.example.com             : ok=14   changed=13   unreachable=0    failed=0
host2.example.com             : ok=14   changed=13   unreachable=0    failed=0

9. Value of mounts:

# df -Th | egrep 'dbvg|Filesystem'
Filesystem                Type      Size  Used Avail Use% Mounted on
/dev/mapper/dbvg-db00 ext4      2.0G  6.0M  1.8G   1% /db00
/dev/mapper/dbvg-db01 ext4      2.0G  6.0M  1.8G   1% /db01
/dev/mapper/dbvg-db02 ext4      2.0G  6.0M  1.8G   1% /db02
/dev/mapper/dbvg-db03 ext4      2.0G  6.0M  1.8G   1% /db03

10. Value of PVS, VGS & LVS:
# pvs
  PV         VG       Fmt  Attr PSize  PFree
  /dev/sda2  cl       lvm2 a--   9.00g     0
  /dev/sdb   dbvg     lvm2 a--  20.00g 12.00g

# vgs
  VG       #PV #LV #SN Attr   VSize  VFree
  cl         1   2   0 wz--n-  9.00g     0
  dbvg       1   4   0 wz--n- 20.00g 12.00g

# lvs
  LV   VG       Attr       LSize Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root cl   -wi-ao---- 8.00g
  swap cl   -wi-ao---- 1.00g
  db00 dbvg -wi-ao---- 2.00g
  db01 dbvg -wi-ao---- 2.00g
  db02 dbvg -wi-ao---- 2.00g
  db03 dbvg -wi-ao---- 2.00g

11. Available entry in fstab:
  # egrep dbvg  /etc/fstab
  /dev/dbvg/db00   /db00   ext4   defaults   0 0
  /dev/dbvg/db01   /db01   ext4   defaults   0 0
  /dev/dbvg/db02   /db02   ext4   defaults   0 0
  /dev/dbvg/db03   /db03   ext4   defaults   0 0


          !!  With the above steps lvm configuration using ansible  is done  !!