166 lines
7.1 KiB
ReStructuredText
166 lines
7.1 KiB
ReStructuredText
==========================
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Set up database clustering
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==========================
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You can store data across multiple machines by setting up MongoDB
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sharded clusters.
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Each cluster includes:
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- One or more *shards*. Each shard consists of a three member replica
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set (three instances organized as a replica set).
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- One or more *query routers*. A query router is the machine that your
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application actually connects to. This machine is responsible for
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communicating with the config server to figure out where the
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requested data is stored. It then accesses and returns the data from
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the appropriate shard(s).
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- One or more *config servers*. Config servers store the metadata that
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links requested data with the shard that contains it.
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This example shows you how to set up a MongoDB sharded cluster.
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.. note:: **Before you begin. **\ Make sure that:
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- The administrative user has registered a MongoDB datastore type and
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version.
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- The administrative user has created an appropriate :ref:`flavor that
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meets the MongoDB minimum requirements <create_db>`.
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Set up clustering
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~~~~~~~~~~~~~~~~~
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#. **Create a cluster**
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Create a cluster by using the trove ``cluster-create`` command. This
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command creates a one-shard cluster. Pass in:
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- The name of the cluster.
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- The name and version of the datastore you want to use.
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- The three instances you want to include in the replication set for
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the first shard. Specify each instance by using the ``--instance``
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argument and the associated flavor ID and volume size. Use the
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same flavor ID and volume size for each instance. In this example,
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flavor ``7`` is a custom flavor that meets the MongoDB minimum
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requirements.
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.. code::
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$ trove cluster-create cluster1 mongodb "2.4" \
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--instance flavor_id=7,volume=2 --instance flavor_id=7,volume=2 \
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--instance flavor_id=7,volume=2
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+-------------------+--------------------------------------+
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| Property | Value |
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+-------------------+--------------------------------------+
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| created | 2014-08-16T01:46:51 |
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| datastore | mongodb |
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| datastore_version | 2.4 |
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| id | aa6ef0f5-dbef-48cd-8952-573ad881e717 |
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| name | cluster1 |
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| task_description | Building the initial cluster. |
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| task_name | BUILDING |
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| updated | 2014-08-16T01:46:51 |
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+-------------------+--------------------------------------+
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#. **Display cluster information**
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Display information about a cluster by using the trove
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``cluster-show`` command. Pass in the ID of the cluster.
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The cluster ID displays when you first create a cluster. (If you need
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to find it later on, use the trove ``cluster-list`` command to list
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the names and IDs of all the clusters in your system.)
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.. code::
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$ trove cluster-show CLUSTER_ID
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+-------------------+--------------------------------------+
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| Property | Value |
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+-------------------+--------------------------------------+
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| created | 2014-08-16T01:46:51 |
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| datastore | mongodb |
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| datastore_version | 2.4 |
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| id | aa6ef0f5-dbef-48cd-8952-573ad881e717 |
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| ip | 10.0.0.2 |
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| name | cluster1 |
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| task_description | No tasks for the cluster. |
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| task_name | NONE |
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| updated | 2014-08-16T01:59:33 |
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+-------------------+--------------------------------------+
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.. note:: **Your application connects to this IP address. **\ The trove
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``cluster-show`` command displays the IP address of the query router.
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This is the IP address your application uses to retrieve data from
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the database.
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#. **List cluster instances**
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List the instances in a cluster by using the trove
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``cluster-instances`` command.
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.. code::
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$ trove cluster-instances CLUSTER_ID
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+--------------------------------------+----------------+-----------+------+
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| ID | Name | Flavor ID | Size |
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+--------------------------------------+----------------+-----------+------+
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| 45532fc4-661c-4030-8ca4-18f02aa2b337 | cluster1-rs1-1 | 7 | 2 |
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| 7458a98d-6f89-4dfd-bb61-5cf1dd65c121 | cluster1-rs1-2 | 7 | 2 |
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| b37634fb-e33c-4846-8fe8-cf2b2c95e731 | cluster1-rs1-3 | 7 | 2 |
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+--------------------------------------+----------------+-----------+------+
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**Naming conventions for replication sets and instances. **\ Note
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that the ``Name`` column displays an instance name that includes the
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replication set name. The replication set names and instance names
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are automatically generated, following these rules:
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- **Replication set name. **\ This name consists of the cluster
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name, followed by the string -rs\ *n*, where *n* is 1 for
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the first replication set you create, 2 for the second replication
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set, and so on. In this example, the cluster name is ``cluster1``,
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and there is only one replication set, so the replication set name
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is ``cluster1-rs1``.
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- **Instance name. **\ This name consists of the replication set
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name followed by the string -*n*, where *n* is 1 for the
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first instance in a replication set, 2 for the second
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instance, and so on. In this example, the instance names are
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``cluster1-rs1-1``, ``cluster1-rs1-2``, and ``cluster1-rs1-3``.
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#. **List clusters**
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List all the clusters in your system, using the trove
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``cluster-list`` command.
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.. code::
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$ trove cluster-list
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+--------------------------------------+----------+-----------+-------------------+-----------+
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| ID | Name | Datastore | Datastore Version | Task Name |
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+--------------------------------------+----------+-----------+-------------------+-----------+
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| aa6ef0f5-dbef-48cd-8952-573ad881e717 | cluster1 | mongodb | 2.4 | NONE |
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| b8829c2a-b03a-49d3-a5b1-21ec974223ee | cluster2 | mongodb | 2.4 | BUILDING |
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+--------------------------------------+----------+-----------+-------------------+-----------+
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#. **Delete a cluster**
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Delete a cluster, using the trove ``cluster-delete`` command.
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.. code::
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$ trove cluster-delete CLUSTER_ID
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Query routers and config servers
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--------------------------------
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Each cluster includes at least one query router and one config server.
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Query routers and config servers count against your quota. When you
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delete a cluster, the system deletes the associated query router(s) and
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config server(s).
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