Upgrade Pt2

[Marc Hoppins <ma...@eset.com>]

Hi all,

What (if any) problems could we expect from an upgrade?

Ie.,  If we have 12 nodes and I upgrade them one-at-a-time, some will be on the new version and others on the old.

Assuming that daily operations continue during this process, could problems occur with streaming replica from one node to another?

Marc

Re: Upgrade Pt2

[Bowen Song via user <us...@cassandra.apache.org>]

Please read 
https://docs.datastax.com/en/upgrading/docs/datastax_enterprise/upgrdCstarToDSE.html#_general_restrictions

The document is written for DSE Cassandra, but must of it applies to 
Apache Cassandra too.

In short, watch out for these:

Client side:

  * Check client driver compatibility.
  * Set the protocol version explicitly in your application.
  * Ensure that the list of initial contact points contains only hosts
    with the oldest Cassandra version or protocol version.

Server side:

  * Do not enable new features.
  * Do not run nodetool repair.
  * During the upgrade, do not bootstrap new nodes or decommission
    existing nodes.
  * Do not enable Change Data Capture (CDC) on a mixed-version cluster.
    Upgrade all nodes to DSE 5.1 (equivalent to Apache Cassandra 3.10)
    or later before enabling CDC.
  * Complete the cluster-wide upgrade before the expiration of
    gc_grace_seconds (approximately 13 days) to ensure any repairs
    complete successfully.
  * Do not issue TRUNCATE or DDL related queries during the upgrade process.

In addition, if using relevant security features:

  * Do not change security credentials or permissions until the upgrade
    is complete on all nodes.
  * If you are not already using Kerberos, do not set up Kerberos
    authentication before upgrading. First upgrade the cluster, and then
    set up Kerberos.

On 19/10/2022 11:36, Marc Hoppins wrote:
>
> Hi all,
>
> What (if any) problems could we expect from an upgrade?
>
> Ie.,  If we have 12 nodes and I upgrade them one-at-a-time, some will 
> be on the new version and others on the old.
>
> Assuming that daily operations continue during this process, could 
> problems occur with streaming replica from one node to another?
>
> Marc
>