Using Ansible’s Documentation#

Ansible configures Linux (and other OS) VMs to a specification. Writing Ansible playbooks is tricky at first because it’s usually easier to just enter the commands to do the Linux configuration. However, like Terraform, Ansible ensures that the VM is in the configuration you want, even if something has changed or gone wrong. Just like with Terraform you need to use Ansible’s documentation to figure out how to do things. Unlike Terraform, Ansible does not change based on the cloud vendor. In this lab we’ll explore the Ansible Documentation to find out how to format a disk.


Reuse the lab09 directory you created in the Using Terraform’s Documentation lab.

Start Manually#

If you followed the in-class demonstration for the Using Terraform’s Documentation lab you named your extra disk lab09. That will make a block device appear named /dev/disk/by-id/google-lab09. Here are the Linux commands to format and mount the disk:

you@cis91:~$ sudo mkfs.ext4 /dev/disk/by-id/google-lab09
you@cis91:~$ sudo mount /dev/disk/by-id/google-lab09 /mnt 

You can verify that the disk is now available with the df command:

you@cis91:~$ df 
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/root        9974088 1882232   8075472  19% /
devtmpfs          490268       0    490268   0% /dev
tmpfs             494588       0    494588   0% /dev/shm
tmpfs              98920     928     97992   1% /run
tmpfs               5120       0      5120   0% /run/lock
tmpfs             494588       0    494588   0% /sys/fs/cgroup
/dev/loop0         56960   56960         0 100% /snap/core18/2566
/dev/loop1         64768   64768         0 100% /snap/core20/1623
/dev/loop2        308480  308480         0 100% /snap/google-cloud-cli/77
/dev/loop3         69504   69504         0 100% /snap/lxd/22753
/dev/loop4         49152   49152         0 100% /snap/snapd/17029
/dev/sda15        106858    5321    101537   5% /boot/efi
tmpfs              98916       0     98916   0% /run/user/1002
/dev/sdb        16337788      24  15482520   1% /mnt

If you want to make the filesystem available after a reboot you have to add a line to the /etc/fstab file:

you@cis91:~$ echo "/dev/disk/by-id/google-lab09 /mnt ext4 defaults 0 0" | sudo tee -a /etc/fstab 

Use Google to Figure Out Ansible#

We want Ansible to do the steps, instead of doing them manually. That way we can be sure they’re applied correctly and repeatably. I have found that the best way to learn how to do things in Ansible is by searching the documentation with Google. Google the term “format filesystem ansible”. At the bottom of the page there are examples. Ansible examples are super helpful! Use an example to do the equivalent of the mkfs.ext4 command.

Now search Google for, “mount filesystem ansible”. Use the first example (Mount DVD) and do some modifications. Here’s what the task should look like:

- name: Mount my filesystem
    path: /mnt
    src: /dev/disk/by-id/google-lab09 
    fstype: ext4
    opts: defaults
    state: present

Turn In#

There’s nothing to turn in. This is just for practice.