Galera Cluster starting backup can't find innobackupex in the path
MariaDB Galera Cluster is a synchronous multi-master cluster.
The most recent MariaDB Galera Cluster 5.5 release is:
MariaDB Galera Cluster 5.5.63 Download Now
The current versions of the Galera wsrep provider library are 26.4.7 for Galera 4 and 25.3.32 for Galera 3.
For convenience, packages containing these libraries are included in the MariaDB YUM and APT repositories.
Answer
See if this helps you out: https://mariadb.com/kb/en/xtrabackup-sync-method/
"Resolved. The answer was to run wsrep_sst_xtrabackup manually, view the error, then look at the code to see that 'which' needed to be installed! yum install which. Once that had been done the second node successfully ran xtrabackup and syncronized the cluster."