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>
