To upgrade a Couchbase-Server cluster means to revise upwards the version of Couchbase Server that is running on every node.
To upgrade a Couchbase-Server cluster means to revise upwards the version of the server that is running on every node. For example, a cluster each of whose nodes has been running Couchbase Server Enterprise Edition Version 6.6 is modified; such that each of its nodes subsequently runs Couchbase Server Enterprise Edition Version 7.0.
An upgrade procedure, like an install procedure, involves both preparation routines and specific upgrade commands that are performed on each individual node. To be upgraded, a cluster must have each of its nodes individually upgraded in turn; and the upgrade procedure for the cluster must therefore be selected with regards to whether the cluster is required to continue serving data, or to cease serving data, during the course of the cluster-upgrade. A review of the factors that determine the appropriateness of an upgrade-procedure is provided in Upgrade Procedure-Selection.
An upgrade path declares that the upgrade of one version of Couchbase Server to another is supported. The tables in the following subsections list upgrade paths for Enterprise Edition and for Community Edition, respectively. Each instance of the sign → declares support for the upgrade of the server-version on the left of the sign to the server-version on the right. Note that upgrade between non-adjacent version-numbers is frequently not supported: for example, to upgrade from 5.5.0+ to 7.0, upgrade must be performed twice; first from 5.5.0+ to 6.6, and secondly from 6.6 to 7.0.
All supported upgrades can be performed with the cluster either offline or online.
|Starting Version||Path to Current Version|
5.0.x and 5.1.x → 6.0.4+ → 6.6 → 7.0
5.0.x and 5.1.x → 6.6 → 7.0
5.5.0+ → 6.6 → 7.0
6.x → 7.0
To upgrade a cluster running Community Edition to a cluster running Enterprise Edition, the version-number of the Enterprise Edition must be identical to that of the Community Edition. Therefore, if the target version-number of the Enterprise Edition is higher, the cluster should first be upgraded to the Enterprise version-number that is identical to the Community Edition version-number, then upgraded to the higher Enterprise Edition version-number, according to the paths described above, in Supported Upgrade Paths.
See Upgrade Procedure-Selection, for a list of procedures that can be used when upgrading from Community Edition to Enterprise. Note, however, that Graceful Failover for Data Service nodes, with Delta Recovery, is not supported for such upgrades: instead, removal, addition, and swap rebalance should be used; for all nodes.
Once an upgrade of a Couchbase-Server cluster has started, downgrade to the earlier version of Couchbase Server can be performed, provided that one node continues to run the earlier version. However, once all nodes are running the later version, downgrade can no longer be performed: therefore, once all nodes are running the later version, should application-support require the earlier version, an entirely new cluster must be created, running the earlier version.