RH294 - ch09s07

Bookmark this page

Managing Storage

Objectives

After completing this section, you should be able to partition storage devices, configure LVM, format partitions or logical volumes, mount file systems, and add swap files or spaces.

Configuring Storage with Ansible Modules

Red Hat Ansible Automation Platform provides a collection of modules to configure storage devices on managed hosts. Those modules support partitioning devices, creating logical volumes, and creating and mounting filesystems.

The `parted` Module

The parted module supports the partition of block devices. This module includes the functionality of the parted command, and allows to create partitions with a specific size, flag, and alignment. The following table lists some of the parameters for the parted module.

Parameter name	Description
align	Configures partition alignment.
device	Block device.
flags	Flags for the partition.
number	The partition number.
part_end	Partition size from the beginning of the disk specified in `parted` supported units.
state	Creates or removes the partition.
unit	Size units for the partition information.

The following example creates a new partition of 10 GB.

- name: New 10GB partition
  parted:
    device: /dev/vdb 
    number: 1 
    state: present 
    part_end: 10GB

	Uses `vdb` as the block device to partition.
	Creates the partition number one.
	Ensures the partition is available.
	Sets the partition size to 10 GB.

The `lvg` and `lvol` Modules

The lvg and lvol modules support the creation of logical volumes, including the configuration of physical volumes, and volume groups. The lvg takes as parameters the block devices to configure as the back end physical volumes for the volume group. The following table lists some of the parameters for the lvg module.

Parameter name	Description
pesize	The size of the physical extent. Must be a power of 2, or multiple of 128 KiB.
pvs	List of comma-separated devices to be configured as physical volumes for the volume group.
vg	The name of the volume group.
state	Creates or removes the volume.

The following task creates a volume group with a specific physical extent size using a block device as a back end.

- name: Creates a volume group
  lvg:
    vg: vg1 
    pvs: /dev/vda1 
    pesize: 32

	The volume group name is `vg1`.
	Uses `/dev/vda1` as the back end physical volume for the volume group.
	Sets the physical extent size to `32`.

In the following example, if the vg1 volume group is already available with /dev/vdb1 as a physical volume, the volume is enlarged adding a new physical volume with /dev/vdc1.

- name: Resize a volume group
  lvg:
    vg: vg1
    pvs: /dev/vdb1,/dev/vdc1

The lvol module creates logical volumes, and supports the resizing and shrinking of those volumes, and the filesystems on top of them. This module also supports the creation of snapshots for the logical volumes. The following table lists some of the parameters for the lvol module.

Parameter name	Description
lv	The name of the logical volume.
resizefs	Resizes the filesystem with the logical volume.
shrink	Enable logical volume shrink.
size	The size of the logical volume.
snapshot	The name of the snapshot for the logical volume.
state	Create or remove the logical volume.
vg	The parent volume group for the logical volume.

The following task creates a logical volume of 2 GB.

- name: Create a logical volume of 2GB
  lvol:
    vg: vg1 
    lv: lv1 
    size: 2g

	The parent volume group name is `vg1`.
	The logical volume name is `lv1`.
	The size of the logical volume is 2 GB.

The `filesystem` Module

The filesystem module supports both creating and resizing a filesystem. This module supports filesystem resizing for ext2, ext3, ext4, ext4dev, f2fs, lvm, xfs, and vfat. The following table lists some of the parameters for the filesystem module.

Parameter name	Description
dev	Block device name.
fstype	Filesystem type.
resizefs	Grows the filesystem size to the size of the block device.

The following example creates a filesystem on a partition.

- name: Create an XFS filesystem
  filesystem:
    fstype: xfs 
    dev: /dev/vdb1

	Uses the `XFS` filesystem.
	Uses the `/dev/vdb1` device.

The `mount` Module

The mount module supports the configuration of mount points on /etc/fstab. The following table lists some of the parameters for the mount module.

Parameter name	Description
fstype	Filesystem type.
opts	Mount options.
path	Mount point path.
src	Device to be mounted.
state	Specify the mount status. If set to `mounted`, the system mounts the device, and configures `/etc/fstab` with that mount information. To unmount the device and remove it from `/etc/fstab` use `absent`.

The following example mounts a device with an specific ID.

- name: Mount device with ID
  mount:
    path: /data 
    src: UUID=a8063676-44dd-409a-b584-68be2c9f5570 
    fstype: xfs 
    state: present

	Uses `/data` as the mount point path.
	Mounts the device with the `a8063676-44dd-409a-b584-68be2c9f5570` ID.
	Uses the `XFS` filesystem.
	Mounts the device and configures `/etc/fstab` accordingly.

The following example mounts the NFS share available at 172.25.250.100:/share on the /nfsshare directory at the managed host.

- name: Mount NFS share
  mount:
    path: /nfsshare
    src: 172.25.250.100:/share
    fstype: nfs
    opts: defaults
    dump: '0'
    passno: '0'
    state: mounted

Configuring swap with Modules

Red Hat Ansible Automation Platform does not currently include modules to manage swap memory. To add swap memory to a system with Ansible with logical volumes you need to create a new volume group and logical volume with the lvg and lvol modules. When ready, you need to format as swap the new logical volume using the command module with the mkswap command. Finally, you need to activate the new swap device using the command module with the swapon command. Ansible includes the ansible_swaptotal_mb variable which includes the total swap memory. You can use this variable to trigger swap configuration and enablement when swap memory is low. The following tasks, create a volume group and a logical volume for swap memory, format that logical volume as swap, and activates it.

- name: Create new swap VG
  lvg:
    vg: vgswap
    pvs: /dev/vda1
    state: present

- name: Create new swap LV
  lvol:
    vg: vgswap
    lv: lvswap
    size: 10g

- name: Format swap LV
  command: mkswap /dev/vgswap/lvswap
  when: ansible_swaptotal_mb < 128

- name: Activate swap LV
  command: swapon /dev/vgswap/lvswap
  when: ansible_swaptotal_mb < 128

Ansible Facts for Storage Configuration

Ansible uses facts to retrieve information to the control node about the configuration of the managed hosts. You can use the setup Ansible module to retrieve all the Ansible facts for a managed host.

[user@controlnode ~]$ ansible webservers -m setup
host.lab.example.com | SUCCESS => {
    "ansible_facts": {
...output omitted...
    }

The filter option for the setup module supports fine-grained filtering based on shell-style wildcards.

The ansible_devices element includes all the storage devices available on the managed host. The element for each storage device includes additional information like partitions or total size. The following example displays the ansible_devices element for a managed host with three storage devices: sr0, vda, and vdb.

[user@controlnode ~]$ ansible webservers -m setup -a 'filter=ansible_devices'
host.lab.example.com | SUCCESS => {
    "ansible_facts": {
        "ansible_devices": {
            "sr0": {
                "holders": [],
                "host": "IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II]",
                "links": {
                    "ids": [
                        "ata-QEMU_DVD-ROM_QM00003"
                    ],
                    "labels": [],
                    "masters": [],
                    "uuids": []
                },
                "model": "QEMU DVD-ROM",
                "partitions": {},
                "removable": "1",
                "rotational": "1",
                "sas_address": null,
                "sas_device_handle": null,
                "scheduler_mode": "mq-deadline",
                "sectors": "2097151",
                "sectorsize": "512",
                "size": "1024.00 MB",
                "support_discard": "0",
                "vendor": "QEMU",
                "virtual": 1
            },
            "vda": {
                "holders": [],
                "host": "SCSI storage controller: Red Hat, Inc. Virtio block device",
                "links": {
                    "ids": [],
                    "labels": [],
                    "masters": [],
                    "uuids": []
                },
                "model": null,
                "partitions": {
                    "vda1": {
                        "holders": [],
                        "links": {
                            "ids": [],
                            "labels": [],
                            "masters": [],
                            "uuids": [
                                "a8063676-44dd-409a-b584-68be2c9f5570"
                            ]
                        },
                        "sectors": "20969439",
                        "sectorsize": 512,
                        "size": "10.00 GB",
                        "start": "2048",
                        "uuid": "a8063676-44dd-409a-b584-68be2c9f5570"
                    }
                },
                "removable": "0",
                "rotational": "1",
                "sas_address": null,
                "sas_device_handle": null,
                "scheduler_mode": "mq-deadline",
                "sectors": "20971520",
                "sectorsize": "512",
                "size": "10.00 GB",
                "support_discard": "0",
                "vendor": "0x1af4",
                "virtual": 1
            },
            "vdb": {
                "holders": [],
                "host": "SCSI storage controller: Red Hat, Inc. Virtio block device",
                "links": {
                    "ids": [],
                    "labels": [],
                    "masters": [],
                    "uuids": []
                },
                "model": null,
                "partitions": {},
                "removable": "0",
                "rotational": "1",
                "sas_address": null,
                "sas_device_handle": null,
                "scheduler_mode": "mq-deadline",
                "sectors": "10485760",
                "sectorsize": "512",
                "size": "5.00 GB",
                "support_discard": "0",
                "vendor": "0x1af4",
                "virtual": 1
            }
        }
    },
    "changed": false
}

The ansible_device_links element includes all the links available for each storage device. The following example displays the ansible_device_links element for a managed host with two storage devices, sr0 and vda1, which have an associated ID.

[user@controlnode ~]$ ansible webservers -m setup -a 'filter=ansible_device_links'
host.lab.example.com | SUCCESS => {
    "ansible_facts": {
        "ansible_device_links": {
            "ids": {
                "sr0": [
                    "ata-QEMU_DVD-ROM_QM00003"
                ]
            },
            "labels": {},
            "masters": {},
            "uuids": {
                "vda1": [
                    "a8063676-44dd-409a-b584-68be2c9f5570"
                ]
            }
        }
    },
    "changed": false
}

The ansible_mounts element includes information about the current mounted devices on the managed host, like the mounted device, the mount point, and the options. The following output displays the ansible_mounts element for a managed host with one active mount, /dev/vda1 on the / directory.

[user@controlnode ~]$ ansible webservers -m setup -a 'filter=ansible_mounts'
host.lab.example.com | SUCCESS => {
    "ansible_facts": {
        "ansible_mounts": [
            {
                "block_available": 2225732,
                "block_size": 4096,
                "block_total": 2618619,
                "block_used": 392887,
                "device": "/dev/vda1",
                "fstype": "xfs",
                "inode_available": 5196602,
                "inode_total": 5242304,
                "inode_used": 45702,
                "mount": "/",
                "options": "rw,seclabel,relatime,attr2,inode64,noquota",
                "size_available": 9116598272,
                "size_total": 10725863424,
                "uuid": "a8063676-44dd-409a-b584-68be2c9f5570"
            }
        ]
    },
    "changed": false
}

References

parted - Configure block device partitions — Ansible Documentation

lvg - Configure LVM volume groups — Ansible Documentation

lvol - Configure LVM logical volumes — Ansible Documentation

filesystem - Makes a filesystem — Ansible Documentation

mount - Control active and configured mount points — Ansible Documentation

Discuss Red Hat Enterprise Linux Automation with Ansible

Go to community

Red Hat Linux Automation with Ansible (RH294)

Haley_Ruccio

24 lip 2023

Learn how to automate Linux system administration tasks with Red Hat Ansible Automation PlatformRed Hat Enterprise Linux Automation with Ansible (RH294) is designed for Linux administrators and developers who need to automate repeatable and error-prone steps for system provisioning, configuration, application deployment, and orchestration. This course is based on Red Hat® Enterprise Linux® 9 and Red Hat Ansible Automation Platform 2.2.Course content summaryInstall Red Hat Ansible Automation Platform on control nodes.Create and update inventories of managed hosts and manage connections to them.Automate administration tasks with Ansible Playbooks and ad hoc commands.Write effective playbooks at scale.Protect sensitive data used by Ansible Automation Platform with Ansible Vault.Reuse code and simplify playbook development with Ansible Roles and Ansible Content Collections.Audience for this courseThis course is geared toward Linux system administrators, DevOps engineers, infrastructure automation engineers, and systems design engineers who are responsible for these tasks:Automating configuration managementEnsuring consistent and repeatable application deploymentProvisioning and deployment of development, testing, and production serversIntegrating with DevOps continuous integration/continuous delivery workflowsPrerequisites for this coursePass the Red Hat Certified System Administrator (RHCSA) exam (EX200), or demonstrate equivalent Red Hat Enterprise Linux knowledge and experience.Take our free assessment to gauge whether this offering is the best fit for your skills.

980

curl finds no route to host?

TPeters

23 lip 2023

I am doing the self-paced course RH294 . With two exercises (Ch.3 final Lab and Ch.4 lab exercise 2) I ran into this problem:after installing and starting a web service, from the classroom web termicaI I cannot reach servera.lab.example.com with curl: "No route to host". This despite the fact that I can ping it, open a shell to it, and install the package on it with Ansible.Anyone else have the same problem?What might be the cause?

1702

Welcome to the Red Hat Linux Automation with Ansible (RH294) group in the Red Hat Learning Community

cschunke

18 lip 2023

We are excited to launch a space dedicated to the Red Hat Training course Red Hat Linux Automation with Ansible! To gain the most value from this group - click the "Join Group" button in the upper right hand corner.We encourage group members to collaborate in this group to discuss topics, ask questions, share best practices and tips, provide course feedback, and share their accomplishments as it relates to RH294.Read more about Red Hat Linux Automation with Ansible here.

351

Revision: rh294-8.4-9cb53f0

Red Hat Enterprise Linux Automation with Ansible