mirror of https://github.com/ceph/ceph
141 lines
6.2 KiB
ReStructuredText
141 lines
6.2 KiB
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=============================
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Block Devices and CloudStack
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=============================
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You may use Ceph Block Device images with CloudStack 4.0 and higher through
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``libvirt``, which configures the QEMU interface to ``librbd``. Ceph stripes
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block device images as objects across the cluster, which means that large Ceph
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Block Device images have better performance than a standalone server!
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To use Ceph Block Devices with CloudStack 4.0 and higher, you must install QEMU,
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``libvirt``, and CloudStack first. We recommend using a separate physical host
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for your CloudStack installation. CloudStack recommends a minimum of 4GB of RAM
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and a dual-core processor, but more CPU and RAM will perform better. The
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following diagram depicts the CloudStack/Ceph technology stack.
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.. ditaa:: +---------------------------------------------------+
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| CloudStack |
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+---------------------------------------------------+
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| libvirt |
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+------------------------+--------------------------+
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| configures
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v
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+---------------------------------------------------+
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| QEMU |
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+---------------------------------------------------+
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| librbd |
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+---------------------------------------------------+
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| librados |
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+------------------------+-+------------------------+
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| OSDs | | Monitors |
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+------------------------+ +------------------------+
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.. important:: To use Ceph Block Devices with CloudStack, you must have
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access to a running Ceph Storage Cluster.
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CloudStack integrates with Ceph's block devices to provide CloudStack with a
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back end for CloudStack's Primary Storage. The instructions below detail the
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setup for CloudStack Primary Storage.
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.. note:: We recommend installing with Ubuntu 14.04 or later so that
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you can use package installation instead of having to compile
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libvirt from source.
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.. note:: Make sure the /tmp partition on your hypervisors is at least 25GB.
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When deploying from a template from the first time /tmp will be used for
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converting the template from QCOW2 to RAW for storage on RBD. This is no
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longer valid starting from CloudStack version 4.4.0
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.. note:: To use RBD with CloudStack 4.4.0 you require at least librbd version
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0.67.7 (Ceph Dumpling). Otherwise template deployments and template backups
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will fail. In case you use Ubuntu we recommend at least LTS version 14.04
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Installing and configuring QEMU for use with CloudStack doesn't require any
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special handling. Ensure that you have a running Ceph Storage Cluster. Install
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QEMU and configure it for use with Ceph; then, install ``libvirt`` version
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0.9.13 or higher (you may need to compile from source) and ensure it is running
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with Ceph.
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.. note:: Raring Ringtail (13.04) will have ``libvirt`` version 0.9.13 or higher
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with RBD storage pool support enabled by default.
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.. index:: pools; CloudStack
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Create a Pool
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=============
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By default, Ceph block devices use the ``rbd`` pool. Create a pool for
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CloudStack NFS Primary Storage. Ensure your Ceph cluster is running, then create
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the pool. ::
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ceph osd pool create cloudstack
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See `Create a Pool`_ for details on specifying the number of placement groups
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for your pools, and `Placement Groups`_ for details on the number of placement
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groups you should set for your pools.
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Create a Ceph User
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==================
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To access the Ceph cluster we require a Ceph user which has the correct
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credentials to access the ``cloudstack`` pool we just created. Although we could
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use ``client.admin`` for this, it's recommended to create a user with only
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access to the ``cloudstack`` pool. ::
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ceph auth get-or-create client.cloudstack mon 'allow r' osd 'allow class-read object_prefix rbd_children, allow rwx pool=cloudstack'
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Use the information returned by the command in the next step when adding the
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Primary Storage.
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See `User Management`_ for additional details.
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Add Primary Storage
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===================
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To add primary storage, refer to `Add Primary Storage (4.2.0)`_ to add a Ceph block device, the steps
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include:
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#. Log in to the CloudStack UI.
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#. Click **Infrastructure** on the left side navigation bar.
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#. Select the Zone you want to use for Primary Storage.
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#. Click the **Compute** tab.
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#. Select **View All** on the `Primary Storage` node in the diagram.
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#. Click **Add Primary Storage**.
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#. Follow the CloudStack instructions.
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- For **Protocol**, select ``RBD``.
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- Add cluster information (cephx is supported). Note: Do not include the ``client.`` part of the user.
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- Add ``rbd`` as a tag.
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Create a Disk Offering
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======================
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To create a new disk offering, refer to `Create a New Disk Offering (4.2.0)`_.
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Create a disk offering so that it matches the ``rbd`` tag.
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The ``StoragePoolAllocator`` will choose the ``rbd``
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pool when searching for a suitable storage pool. If the disk offering doesn't
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match the ``rbd`` tag, the ``StoragePoolAllocator`` may select the pool you
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created (e.g., ``cloudstack``).
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Limitations
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===========
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- CloudStack will only bind to one monitor (You can however create a Round Robin DNS record over multiple monitors)
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- You may need to compile ``libvirt`` to use version 0.9.13 with Ubuntu.
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.. _Create a Pool: ../../rados/operations/pools#createpool
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.. _Placement Groups: ../../rados/operations/placement-groups
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.. _Install and Configure QEMU: ../qemu-rbd
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.. _Install and Configure libvirt: ../libvirt
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.. _KVM Hypervisor Host Installation: http://cloudstack.apache.org/docs/en-US/Apache_CloudStack/4.2.0/html/Installation_Guide/hypervisor-kvm-install-flow.html
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.. _Add Primary Storage (4.2.0): http://cloudstack.apache.org/docs/en-US/Apache_CloudStack/4.2.0/html/Admin_Guide/primary-storage-add.html
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.. _Create a New Disk Offering (4.2.0): http://cloudstack.apache.org/docs/en-US/Apache_CloudStack/4.2.0/html/Admin_Guide/compute-disk-service-offerings.html#creating-disk-offerings
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.. _User Management: ../../rados/operations/user-management
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