openstack/trove
Code Issues Proposed changes
40821578f9
trove/doc/source/user/upgrade-cluster-datastore.rst
Przemysław Godek 2fd324357b Add Redis datastore upgrade 
This patch adds support for upgrading Redis datastore - both single
instance and cluster.

It is achievied in a similar way to MySQL/Mariadb. Steps are:
    + For each node do:
        + stop database
        + preserve configuration files,
        + unmount data volume,
        + create new instance with new datastore,
        + enter restarting mode
        + mount data volume,
        + restore configuration files,
        + reload datastore

Note that due to the Redis Cluster design and Trove approach (all
nodes are master nodes) we do not perform real rolling upgrade - some
Redis slots may be unavailable while upgrading node associated with
them.

This patch adds also a user documentation about upgrading datastores
using Redis as an example.

Story: #2005421
Task: #30443
Co-Authored-By: Kasper Hasior <k.hasior@samsung.com>
Change-Id: I60cddb3a41d2cc7024cbec3d2fd2038d79446507
Signed-off-by: Kasper Hasior <k.hasior@samsung.com>
2019-05-16 13:07:00 +00:00

3.1 KiB
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Upgrade cluster datastore

Upgrading datastore for cluster instances is very similar to upgrading a single instance.

Trove tries to perform a rolling upgrade so that there won't be any downtime. However, it is not always possible and, for example, in case of Redis upgrade, some of its slots may be temporarily unavailable.

Trove strategy upgrades every instance in the entire cluster one by one. Upgrading is finished once all instances are upgraded.

Please check the guide for datastore upgrade to check prerequisistes.

This example shows you how to upgrade Redis datastore (version 3.2.6) for a cluster.

Upgrading cluster

  1. Check cluster task

    Use openstack database cluster list to check whether the task of your cluster is NONE.

    $openstack database cluster list
 +--------------------------------------+---------------+-----------+-------------------+-----------+
 | ID                                   | Name          | Datastore | Datastore Version | Task Name |
 +--------------------------------------+---------------+-----------+-------------------+-----------+
 | 05f2e7b7-8dac-453f-ad5d-38195cd5718f | redis_cluster | redis     | 3.2.6             | NONE      |
 +--------------------------------------+---------------+-----------+-------------------+-----------+

  2. Check if target version is available

    Use openstack datastore version list to list all available versions your datastore.

    $openstack datastore version list redis
 +--------------------------------------+-------+
 | ID                                   | Name  |
 +--------------------------------------+-------+
 | 483debec-b7c3-4167-ab1d-1765795ed7eb | 3.2.6 |
 | 507f666e-193c-4194-9d9d-da8342dcb4f1 | 3.2.7 |
 +--------------------------------------+-------+

  3. Run cluster-upgrade

    Use openstack database cluster upgrade command to upgrade your datastore for the selected instance.

    $openstack database cluster upgrade 05f2e7b7-8dac-453f-ad5d-38195cd5718f 3.2.7

  4. Wait until task changes from UPGRADING_CLUSTER to NONE

    You can use openstack database cluster list to check the current task.

    $openstack database cluster list
 +--------------------------------------+---------------+-----------+-------------------+-----------+
 | ID                                   | Name          | Datastore | Datastore Version | Task Name |
 +--------------------------------------+---------------+-----------+-------------------+-----------+
 | 05f2e7b7-8dac-453f-ad5d-38195cd5718f | redis_cluster | redis     | 3.2.7             | NONE      |
 +--------------------------------------+---------------+-----------+-------------------+-----------+

Other clusters

Upgrade for other clusters works in the same way. Currently Trove supports upgrades for the following cluster datastores:

  • MySQL.
  • MariaDB.
  • Redis.