Percona Xtradb Cluster upgrade

Hi team,

l have 3 nodes running Percona Xtradb Cluster 5.7 version. Now l want to upgrdae them to version 8. For downtime requirement l want to do it like rolling upgrade. One node at a time. Is it possible doing major upgarde in Xtardb cluster? l read document that it is possible and l did it on node 3 but when starting mysqld service my node joined cluster with joiner state and thats totally normal but in the logs it stucks like this

joiner side:

Note] [MY-000000] [WSREP-SST] …Waiting for SST streaming to complete!

on donor side also in the logs l see

[Note] WSREP: Initiating SST/IST transfer on DONOR side (wsrep_sst_xtrabackup-v2 --role ‘donor’ --address ‘xx.xx.xxx:4444/xtrabackup_sst//1’ --socket ‘/var/lib/mysql/mysql.sock’ --datadir ‘/var/lib/mysql/’ --defaults-file ‘/etc/my.cnf’ --defaults-group-suffix ‘’ --mysqld-version ‘5.7.42-46-57’ --binlog ‘binlog’ --gtid ‘c11ed0aa-0c3b-11ee-b9dd-731cc246b6e6:572053310’ )

[Note] WSREP: DONOR thread signaled with 0

WSREP_SST: [INFO] Streaming with xbstream

[Note] WSREP: (078eaf51, ‘ssl://0.0.0.0:4567’) turning message relay requesting off

WSREP_SST: [INFO] Streaming the backup to joiner at xxxxxxx 4444

5.7 version uses galera 3, 8 version uses galera 4.

l updated packages on joiner and see logs that it upgraded data dir. But at the end it stucks. Why is that? Can you help me plsss? @matthewb @CTutte

joiner.log (2.5 KB)

donor.log (1.1 KB)

With this upgrade method, please ensure that the 8.0 node joins the cluster (2 nodes with 5.7) through IST rather than SST. Based on the logs, it is currently triggering SST. Please verify that you have sufficient gcache size configured to continue the instance with IST.

2025-12-08T07:29:36.164484Z 2 [Note] [MY-000000] [Galera] State gap can't be serviced using IST. Switching to SST