Skip to content

Latest commit

 

History

History
147 lines (107 loc) · 5.58 KB

openstack-volume.md

File metadata and controls

147 lines (107 loc) · 5.58 KB

Managing OpenStack Storage, Instance Volumes, and Backups. Let's go through your questions one by one.

1. Where are instance volumes stored?

When you create an instance in OpenStack without selecting create new volume, the instance uses ephemeral storage. This storage is temporary and is deleted when the instance is terminated. The ephemeral storage is typically located in the /var/lib/nova/instances directory on the compute node.

For persistent storage, OpenStack uses the Cinder service to manage volumes. These volumes are stored on block storage devices and can be attached to instances. By default, Cinder uses LVM (Logical Volume Manager) as the backend, but you can configure it to use other storage backends like Ceph, NFS, or third-party storage solutions.

2. How to automatically backup instance volumes?

To automatically backup instance volumes in OpenStack, you can use the Cinder service's backup feature. Here are the steps to create a backup:

  1. Create a Backup:

    openstack volume backup create --name <backup_name> <volume_id>

    You can also create incremental backups by adding the --incremental flag.

  2. Restore a Backup:

    openstack volume backup restore <backup_id> <volume_id>

For automation, you can set up a cron job or use OpenStack's built-in scheduling services to run these commands at regular intervals.

3. How to use external storage with OpenStack for storing instance volumes?

You can integrate external storage solutions with OpenStack using the Cinder service. Here are the general steps:

  1. Configure Cinder to Use External Storage:

    • Edit the /etc/cinder/cinder.conf file to add the configuration for your external storage backend. For example, to use NFS: 
      [DEFAULT]
enabled_backends = nfs

[nfs]
volume_driver = cinder.volume.drivers.nfs.NfsDriver
nfs_shares_config = /etc/cinder/nfs_shares
    • Create the /etc/cinder/nfs_shares file and add the NFS server details: 
      nfs-server:/exported/path

  2. Restart Cinder Services:

    systemctl restart openstack-cinder-api
systemctl restart openstack-cinder-scheduler
systemctl restart openstack-cinder-volume

  3. Create Volumes Using the External Storage: When creating a volume, specify the backend:

    openstack volume create --size <size> --volume-type nfs <volume_name>

Summary

  • Instance Volumes: Ephemeral storage is used by default, located at /var/lib/nova/instances. Persistent volumes are managed by Cinder.
  • Automatic Backup: Use Cinder's backup feature and automate with cron jobs or scheduling services.
  • External Storage: Configure Cinder to use external storage backends like NFS, Ceph, etc.

Since your instances are using ephemeral storage, their volumes are stored on the local disk of the compute node. You can find these volumes in the /var/lib/nova/instances directory on the compute node where the instances are running.

Locating Instance Volumes

  1. SSH into the Compute Node:

    ssh <compute_node_ip>

  2. Navigate to the Instances Directory:

    cd /var/lib/nova/instances

  3. List the Instances: You will see directories named after the instance UUIDs. Each directory contains the disk files for the corresponding instance.

Backing Up Ephemeral Volumes

Backing up ephemeral volumes can be a bit tricky since they are meant to be temporary. However, you can create snapshots of the instances to preserve their state.

  1. Create a Snapshot of an Instance:

    openstack server snapshot create --name <snapshot_name> <instance_id>

  2. Verify the Snapshot:

    openstack image list

    You should see your snapshot listed as an image.

Automating Backups

To automate the backup process, you can use a script and a cron job. Here’s a simple example:

  1. Create a Backup Script:

    nano /usr/local/bin/backup_instances.sh

    Add the following content to the script:

    #!/bin/bash
INSTANCE_IDS=$(openstack server list -f value -c ID)
for ID in $INSTANCE_IDS; do
    openstack server snapshot create --name backup_$ID $(date +%Y%m%d%H%M%S) $ID
done

  2. Make the Script Executable:

    chmod +x /usr/local/bin/backup_instances.sh

  3. Set Up a Cron Job:

    crontab -e

    Add the following line to run the script daily at midnight:

    0 0 * * * /usr/local/bin/backup_instances.sh

Summary

  • Locate Volumes: Ephemeral volumes are in /var/lib/nova/instances on the compute node.
  • Backup: Use instance snapshots to back up ephemeral volumes.
  • Automate: Create a script and set up a cron job for regular backups.

Feel free to ask if you need more details or further assistance!

Reference:

(1) Safeguarding Your OpenStack Instance: Complete Guide to

(2) Manage volumes - OpenStack

(3) Chapter 2. Block Storage and Volumes - Red Hat

(4) Back up and restore volumes and snapshots — cinder 25.1.0

(5) Back up and restore volumes and snapshots