My understanding of our process is (assuming we have 3 nodes A,B,C): - Add A' to the cluster with the same keyspace as A. - Remove A from the cluster. - Add B' to the cluster - Remove B from the cluster - Add C' to the cluster - Remove C from the cluster.
Currently these operations have to be performed in sequence. My understanding is that you can't add more than one node at a time. What we would like to do is do this is 3 steps: - Add A', B', C' to the cluster. - Wait for all 3 to be accepted and functioning. - Remove A, B, C from the cluster. Does CEP-21 make this possible? On Thu, Oct 20, 2022 at 1:43 PM Sam Tunnicliffe <s...@beobal.com> wrote: > I'm not sure I 100% understand the question, but the things covered in > CEP-21 won't enable you to as an operator to bootstrap all your new nodes > without fully joining, then perform an atomic CAS to replace the existing > members. CEP-21 alone also won't solve all cross-version streaming issues, > which is one reason performing topology-modifying operations like bootstrap > & decommission during an upgrade are not generally considered a good idea. > > Transactional metadata will make the bootstrapping (and decommissioning) > experience a whole lot more stable and predictable, so in the short term I > would expect the recommended rolling approach to upgrades would improve > significantly. > > > > On 20 Oct 2022, at 12:24, Claude Warren, Jr via dev < > dev@cassandra.apache.org> wrote: > > > > After CEP-21 would it be possible to take a cluster of 6 nodes, spin up > 6 new nodes to duplicate the 6 existing nodes and then spin down the > original 6 nodes. Basically, I am thinking of the case where a cluster is > running version x.y.z and want to run x.y.z+1, can they spin up an equal > number of x.y.z+1 systems and replace the old ones without shutting down > the cluster? > > > > We currently try something like this where we spin up 1 system and then > drop 1 system until all the old nodes are replaced. This process > frequently runs into streaming failures while bootstrapping. > > > > Any insights would be appreciated. > > > > Claude > >
