Install and configure a storage node¶

Prerequisites¶

Before you install and configure the Block Storage service on the storage node, you must prepare the storage device.

1. Install the supporting utility packages:

   # apt install lvm2 thin-provisioning-tools
   

   Note

   Some distributions include LVM by default.

2. Create the LVM physical volume /dev/sdb:

   # pvcreate /dev/sdb
   
   Physical volume "/dev/sdb" successfully created
   

3. Create the LVM volume group cinder-volumes:

   # vgcreate cinder-volumes /dev/sdb
   
   Volume group "cinder-volumes" successfully created
   

   The Block Storage service creates logical volumes in this volume group.

4. Only instances can access Block Storage volumes. However, the underlying operating system manages the devices associated with the volumes. By default, the LVM volume scanning tool scans the /dev directory for block storage devices that contain volumes. If projects use LVM on their volumes, the scanning tool detects these volumes and attempts to cache them which can cause a variety of problems with both the underlying operating system and project volumes. You must reconfigure LVM to scan only the devices that contain the cinder-volumes volume group. Edit the /etc/lvm/lvm.conf file and complete the following actions:

   • In the devices section, add a filter that accepts the /dev/sdb device and rejects all other devices:

     devices {
     ...
     filter = [ "a/sdb/", "r/.*/"]
     

     Each item in the filter array begins with a for accept or r for reject and includes a regular expression for the device name. The array must end with r/.*/ to reject any remaining devices. You can use the vgs -vvvv command to test filters.

     Warning

     If your storage nodes use LVM on the operating system disk, you must also add the associated device to the filter. For example, if the /dev/sda device contains the operating system:

     filter = [ "a/sda/", "a/sdb/", "r/.*/"]
     

     Similarly, if your compute nodes use LVM on the operating system disk, you must also modify the filter in the /etc/lvm/lvm.conf file on those nodes to include only the operating system disk. For example, if the /dev/sda device contains the operating system:

     filter = [ "a/sda/", "r/.*/"]
     

Install and configure components¶

1. Install the packages:

   # apt install cinder-volume
   

2. Edit the /etc/cinder/cinder.conf file and complete the following actions:

   • In the [database] section, configure database access:

     [database]
     # ...
     connection = mysql+pymysql://cinder:CINDER_DBPASS@controller/cinder
     

     Replace CINDER_DBPASS with the password you chose for the Block Storage database.

   • In the [DEFAULT] section, configure RabbitMQ message queue access:

     [DEFAULT]
     # ...
     transport_url = rabbit://openstack:RABBIT_PASS@controller
     

     Replace RABBIT_PASS with the password you chose for the openstack account in RabbitMQ.

   • In the [DEFAULT] and [keystone_authtoken] sections, configure Identity service access:

     [DEFAULT]
     # ...
     auth_strategy = keystone
     
     [keystone_authtoken]
     # ...
     www_authenticate_uri = http://controller:5000
     auth_url = http://controller:5000
     memcached_servers = controller:11211
     auth_type = password
     project_domain_id = default
     user_domain_id = default
     project_name = service
     username = cinder
     password = CINDER_PASS
     

     Replace CINDER_PASS with the password you chose for the cinder user in the Identity service.

     Note

     Comment out or remove any other options in the [keystone_authtoken] section.

   • In the [DEFAULT] section, configure the my_ip option:

     [DEFAULT]
     # ...
     my_ip = MANAGEMENT_INTERFACE_IP_ADDRESS
     

     Replace MANAGEMENT_INTERFACE_IP_ADDRESS with the IP address of the management network interface on your storage node, typically 10.0.0.41 for the first node in the example architecture.

   • In the [lvm] section, configure the LVM back end with the LVM driver, cinder-volumes volume group, iSCSI protocol, and appropriate iSCSI service:

     [lvm]
     # ...
     volume_driver = cinder.volume.drivers.lvm.LVMVolumeDriver
     volume_group = cinder-volumes
     iscsi_protocol = iscsi
     iscsi_helper = tgtadm
     

   • In the [DEFAULT] section, enable the LVM back end:

     [DEFAULT]
     # ...
     enabled_backends = lvm
     

     Note

     Back-end names are arbitrary. As an example, this guide uses the name of the driver as the name of the back end.

   • In the [DEFAULT] section, configure the location of the Image service API:

     [DEFAULT]
     # ...
     glance_api_servers = http://controller:9292
     

   • In the [oslo_concurrency] section, configure the lock path:

     [oslo_concurrency]
     # ...
     lock_path = /var/lib/cinder/tmp
     

Finalize installation¶

1. Restart the Block Storage volume service including its dependencies:

   # service tgt restart
   # service cinder-volume restart