134 lines
5.6 KiB
Markdown
134 lines
5.6 KiB
Markdown
Overview
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--------
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This charm provides the swift-proxy component of the OpenStack Swift object
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storage system. It can be deployed as part of its own stand-alone storage
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cluster or it can be integrated with the other OpenStack components, assuming
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those are also managed by Juju. For Swift to function, you'll also need to
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deploy additional swift-storage nodes using the cs:precise/swift-storage
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charm.
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For more information about Swift and its architecture, visit the [official project website](http://swift.openstack.org)
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This charm was developed to support deploying multiple version of Swift on
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Ubuntu Precise 12.04, as they relate to the release series of OpenStack. That
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is, OpenStack Essex corresponds to Swift 1.4.8 while OpenStack Folsom shipped
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1.7.4. This charm can be used to deploy either (and future) versions of Swift
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onto an Ubuntu Precise 12.04 or Trusty 14.04 making use of the Ubuntu Cloud
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Archive when needed.
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Usage
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-----
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Currently, Swift may be deployed in two ways. In either case, additional
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storage nodes are required. The configuration option that dictates
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how to deploy this charm is the 'zone-assignment' setting. This section
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describes how to select the appropriate zone assignment policy, as well as
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a few other configuration settings of interest. Many of the configuration
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settings can be left as default.
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**Zone Assignment**
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This setting determines how the charm assigns new storage nodes to storage
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zones.
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The default, 'manual' option is suggested for production as it allows
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administrators to carefully architect the storage cluster. It requires each
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swift-storage service to be deployed with an explicit storage zone configured
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in its deployment settings. Upon relation to a swift-proxy, the storage node
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will request membership to its configured zone and be assigned by the
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swift-proxy charm accordingly. Using the cs:precise/swift-storage charm with
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this charm, a deployment would look something like:
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$ cat >swift.cfg <<END
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swift-proxy:
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zone-assignment: manual
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replicas: 3
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swift-storage-zone1:
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zone: 1
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block-device: /etc/swift/storage.img|2G
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swift-storage-zone2:
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zone: 2
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block-device: /etc/swift/storage.img|2G
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swift-storage-zone3:
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zone: 3
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block-device: /etc/swift/storage.img|2G
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END
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$ juju deploy --config=swift.cfg swift-proxy
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$ juju deploy --config=swift.cfg swift-storage swift-storage-zone1
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$ juju deploy --config=swift.cfg swift-storage swift-storage-zone2
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$ juju deploy --config=swift.cfg swift-storage swift-storage-zone3
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$ juju add-relation swift-proxy swift-storage-zone1
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$ juju add-relation swift-proxy swift-storage-zone2
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$ juju add-relation swift-proxy swift-storage-zone3
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This will result in a configured storage cluster of 3 zones, each with one
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node. To expand capacity of the storage system, nodes can be added to specific
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zones in the ring.
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$ juju add-unit swift-storage-zone1
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$ juju add-unit -n5 swift-storage-zone3 # Adds 5 units to zone3
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This charm will not balance the storage ring until there are enough storage
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zones to meet its minimum replica requirement, in this case 3.
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The other option for zone assignment is 'auto'. In this mode, swift-proxy
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gets a relation to a single swift-storage service unit. Each machine unit
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assigned to that service unit will be distributed evenly across zones.
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$ cat >swift.cfg <<END
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swift-proxy:
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zone-assignment: auto
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replicas: 3
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swift-storage:
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zone: 1
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block-device: /etc/swift/storage.img|2G
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END
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$ juju deploy --config=swift.cfg swift-proxy
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$ juju deploy --config=swift.cfg swift-storage
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$ juju add-relation swift-proxy swift-storage
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# The swift-storage/0 unit ends up the first node in zone 1
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$ juju add-unit swift-storage
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# swift-storage/1 ends up the first node in zone 2.
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$ juju add-unit swift-storage
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# swift-storage/2 is the first in zone 3, replica requirement is satisfied
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# the ring is balanced.
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Extending the ring in the case is just a matter of adding more units to the
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single service unit. New units will be distributed across the existing zones.
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$ juju add-unit swift-storage
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# swift-storage/3 is assigned to zone 1.
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$ juju add-unit swift-storage
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# swift-storage/4 is assigned to zone 2.
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etc.
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**Installation repository.**
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The 'openstack-origin' setting allows Swift to be installed from installation
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repositories and can be used to setup access to the Ubuntu Cloud Archive
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to support installing Swift versions more recent than what is shipped with
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Ubuntu 12.04 (1.4.8). For more information, see config.yaml.
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**Authentication.**
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By default, the charm will be deployed using the tempauth auth system. This is
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a simple and not-recommended auth system that functions without any external
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dependencies. See Swift documentation for details.
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The charm may also be configured to use Keystone, either manually (via config)
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or automatically via a relation to an existing Keystone service using the
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cs:precise/keystone charm. The latter is preferred, however, if a Keystone
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service is desired but it is not managed by Juju, the configuration for the
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auth token middleware can be set manually via the charm's config. A relation
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to a Keystone server via the identity-service interface will configure
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swift-proxy with the appropriate credentials to make use of Keystone and is
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required for any integration with other OpenStack components.
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**Glance**
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Swift may be used to as a storage backend for the Glance image service. To do
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so, simply add a relation between swift-proxy and an existing Glance service
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deployed using the cs:precise/glance charm.
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