MariaDB Galera Cluster on EC2 - rsync error

I am trying to create a simple two node cluster; on joining node 2 to the cluster there are errors in the log of node 1. looks to be an rsync permission error on node 1. I am running node 1 and node 2 under the default ec2-user with sudo, whilst setting --user=root. the error on node 1 says:
2016-08-01 12:21:12 139905883698944 [Note] WSREP: Tables flushed.
rsync: open "ibdata1" (in rsync_sst) failed: Permission denied (13)
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1052) [sender=3.0.9]
WSREP_SST: [ERROR] rsync returned code 23: (20160801 12:21:13.022)
2016-08-01 12:21:13 139905883698944 [ERROR] WSREP: Failed to read from: wsrep_sst_rsync --role 'donor' --address '<node2_ip>:4444/rsync_sst' --socket '/var/lib/mysql/mysql.sock' --datadir '/var/lib/mysql/' '' --gtid '3a3e195f-57f1-11e6-92fd-5a5896716e64:0' --gtid-domain-id '0'

How to configure this such that rsync replication works?

thanks