139 lines
4.5 KiB
ReStructuredText
139 lines
4.5 KiB
ReStructuredText
.. _cinder-guide:
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===============
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Cinder in Kolla
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===============
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Overview
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========
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Currently Kolla can deploy the cinder services:
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- cinder-api
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- cinder-scheduler
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- cinder-backup
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- cinder-volume
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The cinder implementation defaults to using LVM storage. The default
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implementation requires a volume group be set up. This can either be
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a real physical volume or a loopback mounted file for development.
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.. note ::
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The Cinder community has closed a bug as WontFix which makes it
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impossible for LVM to be used at all in a multi-controller setup.
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The only option for multi-controller storage to work correctly at
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present is via a Ceph deployment. If community members disagree
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with this decision, please report the specific use case in the
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Cinder bug tracker here:
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`_bug 1571211 <https://launchpad.net/bugs/1571211>`__.
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Create a Volume Group
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=====================
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Use ``pvcreate`` and ``vgcreate`` to create the volume group. For example
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with the devices ``/dev/sdb`` and ``/dev/sdc``:
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::
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<WARNING ALL DATA ON /dev/sdb and /dev/sdc will be LOST!>
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pvcreate /dev/sdb /dev/sdc
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vgcreate cinder-volumes /dev/sdb /dev/sdc
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During development, it may be desirable to use file backed block storage. It
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is possible to use a file and mount it as a block device via the loopback
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system. ::
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mknod /dev/loop2 b 7 2
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dd if=/dev/zero of=/var/lib/cinder_data.img bs=1G count=20
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losetup /dev/loop2 /var/lib/cinder_data.img
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pvcreate /dev/loop2
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vgcreate cinder-volumes /dev/loop2
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Validation
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==========
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Create a volume as follows:
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::
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$ openstack volume create --size 1 steak_volume
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<bunch of stuff printed>
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Verify it is available. If it says "error" here something went wrong during
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LVM creation of the volume. ::
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$ openstack volume list
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+--------------------------------------+--------------+-----------+------+-------------+
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| ID | Display Name | Status | Size | Attached to |
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+--------------------------------------+--------------+-----------+------+-------------+
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| 0069c17e-8a60-445a-b7f0-383a8b89f87e | steak_volume | available | 1 | |
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+--------------------------------------+--------------+-----------+------+-------------+
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Attach the volume to a server using:
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::
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openstack server add volume steak_server 0069c17e-8a60-445a-b7f0-383a8b89f87e
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Check the console log added the disk:
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::
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openstack console log show steak_server
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A ``/dev/vdb`` should appear in the console log, at least when booting cirros.
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If the disk stays in the available state, something went wrong during the
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iSCSI mounting of the volume to the guest VM.
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Cinder LVM2 backend with iSCSI
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==============================
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As of Newton-1 milestone, Kolla supports LVM2 as cinder backend. It is
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accomplished by introducing two new containers ``tgtd`` and ``iscsid``.
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``tgtd`` container serves as a bridge between cinder-volume process and a server
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hosting Logical Volume Groups (LVG). ``iscsid`` container serves as a bridge
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between nova-compute process and the server hosting LVG.
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In order to use Cinder's LVM backend, a LVG named ``cinder-volumes`` should
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exist on the server and following parameter must be specified in
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``globals.yml`` ::
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enable_cinder_backend_lvm: "yes"
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For Ubuntu and LVM2/iSCSI
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~~~~~~~~~~~~~~~~~~~~~~~~~
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``iscsd`` process uses configfs which is normally mounted at
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``/sys/kernel/config`` to store discovered targets information, on centos/rhel
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type of systems this special file system gets mounted automatically, which is
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not the case on debian/ubuntu. Since ``iscsid`` container runs on every nova
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compute node, the following steps must be completed on every Ubuntu server
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targeted for nova compute role.
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- Add configfs module to ``/etc/modules``
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- Rebuild initramfs using: ``update-initramfs -u`` command
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- Stop ``open-iscsi`` system service due to its conflicts
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with iscsid container.
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For Ubuntu 14.04 (upstart): ``service open-iscsi stop``
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Ubuntu 16.04 (systemd):
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``systemctl stop open-iscsi; systemctl stop iscsid``
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- Make sure configfs gets mounted during a server boot up process. There are
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multiple ways to accomplish it, one example:
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::
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mount -t configfs /etc/rc.local /sys/kernel/config
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Cinder backend with external iSCSI storage
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==========================================
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In order to use external storage system (like one from EMC or NetApp)
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the following parameter must be specified in ``globals.yml`` ::
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enable_cinder_backend_iscsi: "yes"
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Also ``enable_cinder_backend_lvm`` should be set to "no" in this case.
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