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diff --git a/doc/source/reference/cinder-guide.rst b/doc/source/reference/cinder-guide.rst new file mode 100644 index 000000000..937e99ac8 --- /dev/null +++ b/doc/source/reference/cinder-guide.rst @@ -0,0 +1,166 @@ +.. _cinder-guide: + +=============== +Cinder in Kolla +=============== + +Overview +======== + +Cinder can be deploying using Kolla and supports the following storage +backends: + +* ceph +* hnas_iscsi +* hnas_nfs +* iscsi +* lvm +* nfs + +LVM +=== + +When using the ``lvm`` backend, a volume group will need to be created on each +storage node. This can either be a real physical volume or a loopback mounted +file for development. Use ``pvcreate`` and ``vgcreate`` to create the volume +group. For example with the devices ``/dev/sdb`` and ``/dev/sdc``: + +:: + + <WARNING ALL DATA ON /dev/sdb and /dev/sdc will be LOST!> + + 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. :: + + + free_device=$(losetup -f) + fallocate -l 20G /var/lib/cinder_data.img + losetup $free_device /var/lib/cinder_data.img + pvcreate $free_device + vgcreate cinder-volumes $free_device + +Enable the ``lvm`` backend in ``/etc/kolla/globals.yml``: + +:: + + enable_cinder_backend_lvm: "yes" + +.. note :: + There are currently issues using the LVM backend in a multi-controller setup, + see `_bug 1571211 <https://launchpad.net/bugs/1571211>`__ for more info. + +NFS +=== + +To use the ``nfs`` backend, configure ``/etc/exports`` to contain the mount +where the volumes are to be stored:: + + /kolla_nfs 192.168.5.0/24(rw,sync,no_root_squash) + +In this example, ``/kolla_nfs`` is the directory on the storage node which will +be ``nfs`` mounted, ``192.168.5.0/24`` is the storage network, and +``rw,sync,no_root_squash`` means make the share read-write, synchronous, and +prevent remote root users from having access to all files. + +Then start ``nfsd``:: + + systemctl start nfs + +On the deploy node, create ``/etc/kolla/config/nfs_shares`` with an entry for +each storage node:: + + storage01:/kolla_nfs + storage02:/kolla_nfs + +Finally, enable the ``nfs`` backend in ``/etc/kolla/globals.yml``:: + + enable_cinder_backend_nfs: "yes" + +Validation +========== + +Create a volume as follows: + +:: + + $ openstack volume create --size 1 steak_volume + <bunch of stuff printed> + +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 back end with iSCSI +=============================== + +As of Newton-1 milestone, Kolla supports LVM2 as cinder back end. 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 Cinder's LVM back end, a LVG named ``cinder-volumes`` should +exist on the server and following parameter must be specified in +``globals.yml`` :: + + enable_cinder_backend_lvm: "yes" + +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 + - Stop ``open-iscsi`` system service due to its conflicts + with iscsid container. + + Ubuntu 16.04 (systemd): + ``systemctl stop open-iscsi; systemctl stop iscsid`` + + - Make sure configfs gets mounted during a server boot up process. There are + multiple ways to accomplish it, one example: + :: + + mount -t configfs /etc/rc.local /sys/kernel/config + +Cinder back end with external iSCSI storage +=========================================== + +In order to use external storage system (like one from EMC or NetApp) +the following parameter must be specified in ``globals.yml`` :: + + enable_cinder_backend_iscsi: "yes" + +Also ``enable_cinder_backend_lvm`` should be set to "no" in this case. |