.. _cinder-guide: =============== Cinder in Kolla =============== Overview ======== Currently Kolla can deploy the cinder services: - cinder-api - cinder-scheduler - cinder-backup - cinder-volume The cinder implementation defaults to using LVM storage. The default implementation requires a volume group be set up. This can either be a real physical volume or a loopback mounted file for development. .. note :: The Cinder community has closed a bug as WontFix which makes it impossible for LVM to be used at all in a multi-controller setup. The only option for multi-controller storage to work correctly at present is via a Ceph deployment. If community members disagree with this decision, please report the specific use case in the Cinder bug tracker here: `_bug 1571211 `__. Create a Volume Group ===================== Use ``pvcreate`` and ``vgcreate`` to create the volume group. For example with the devices ``/dev/sdb`` and ``/dev/sdc``: :: pvcreate /dev/sdb /dev/sdc vgcreate cinder-volumes /dev/sdb /dev/sdc During development, it may be desirable to use file backed block storage. It is possible to use a file and mount it as a block device via the loopback system. :: mknod /dev/loop2 b 7 2 dd if=/dev/zero of=/var/lib/cinder_data.img bs=1G count=20 losetup /dev/loop2 /var/lib/cinder_data.img pvcreate /dev/loop2 vgcreate cinder-volumes /dev/loop2 Validation ========== Create a volume as follows: :: $ openstack volume create --size 1 steak_volume Verify it is available. If it says "error" here something went wrong during LVM creation of the volume. :: $ openstack volume list +--------------------------------------+--------------+-----------+------+-------------+ | ID | Display Name | Status | Size | Attached to | +--------------------------------------+--------------+-----------+------+-------------+ | 0069c17e-8a60-445a-b7f0-383a8b89f87e | steak_volume | available | 1 | | +--------------------------------------+--------------+-----------+------+-------------+ Attach the volume to a server using: :: openstack server add volume steak_server 0069c17e-8a60-445a-b7f0-383a8b89f87e Check the console log added the disk: :: openstack console log show steak_server A ``/dev/vdb`` should appear in the console log, at least when booting cirros. If the disk stays in the available state, something went wrong during the iSCSI mounting of the volume to the guest VM. Cinder LVM2 backend with iSCSI ============================== As of Newton-1 milestone, Kolla supports LVM2 as cinder backend. It is accomplished by introducing two new containers ``tgtd`` and ``iscsid``. tgtd container serves as a bridge between cinder-volume process and a server hosting Logical Volume Groups (LVG). ``iscsid`` container serves as a bridge between nova-compute process and the server hosting LVG. In order to use iSCSI as a Cinder's backend, these two parameters must be specified in ``globals.yml``. :: enable_iscsi: "yes" cinder_volume_group: << lvg_name >> Where: - ``lvg_name`` - is a name of LVG on that server. NOTE: For Ubuntu and LVM2/iSCSI ``iscsd`` process uses configfs which is normally mounted at ``/sys/kernel/config`` to store discovered targets information, on centos/rhel type of systems this special file system gets mounted automatically, which is not the case on debian/ubuntu. Since ``iscsid`` container runs on every nova compute node, the following steps must be completed on every Ubuntu server targeted for nova compute role. - Add configfs module to ``/etc/modules`` - Rebuild initramfs using: ``update-initramfs -u`` command - Make sure configfs gets mounted during a server boot up process. There are multiple ways to accomplish it, one example is adding this command "mount -t configfs configfs ``/sys/kernel/config``" to ``/etc/rc.local``