linuxexpert-practice-labs/labs/ex294/9-4-storage-and-file-systems/README.md

EX294 9.4: Storage and file systems

Partition a disk, make file systems and mount them for good, size a logical volume to what each host has room for, and let the storage system role do the same from variables.

Before you start

This VM is the control node, and here also the host with the disks: localhost ansible_connection=local, in the inventory group storage. The lab creates the user greg (password Lab-Pass-1, sudo without a password) with an SSH key, and installs ansible-core. Work as greg, in /home/greg/ansible: its ansible.cfg reads the inventory inventory, logs in as devops and becomes root. The ansible.posix and community.general collections and the system roles aren't installed yet.

Spare disks on this VM, where the chapter has vdb and friends:

• /dev/loop40, 2 GiB, for task 1
• /dev/loop41, 1 GiB, for task 2
• /dev/loop42, 2 GiB, for task 3

The managed node node1 (10.99.1.11, group nodes) is an AlmaLinux 10 container, prepared as in chapter 3.1: devops takes greg's key and may use sudo without a password. A container has no disks of its own, so it plays the host without the volume group. For a root shell there, sudo podman exec -it node1 bash.

Tasks

1. On the storage hosts, create a 1 GiB partition on /dev/loop40, put XFS on it, and mount it at /srv/archive persistently. findmnt /srv/archive shows it, also after a reboot.
2. Create the volume group research on /dev/loop41 on the storage hosts. Then write /home/greg/ansible/lv.yml for all hosts: a 1500 MiB logical volume data in research where it fits, an 800 MiB one with the message "Could not create logical volume of that size" where it doesn't, ext4 on it mounted at /mnt/data, and the message "Volume group does not exist" on hosts without research. Each host ends with the right size or message, and lvs research agrees.
3. Use the storage system role to make a 1 GiB XFS logical volume on /dev/loop42, mounted at /srv/web. Check with lsblk and /etc/fstab.

Hints

• ansible-galaxy collection install ansible.posix 'community.general:>=11,<12': community.general 12 and later need a newer ansible-core than this one.
• community.general.parted (needs the parted package here), community.general.filesystem, ansible.posix.mount with state: mounted. A partition of /dev/loop40 is /dev/loop40p1.
• community.general.lvg and lvol; block and rescue for the smaller volume; ansible_facts['lvm']['vgs'] says which hosts have research.
• The system roles come from the rhel-system-roles package; in storage_pools, a disk is named like loop42.