node1-conf.d.cluster.cnf

[mysqld]
binlog_format=ROW
bind-address=0.0.0.0
default-storage-engine=innodb
innodb_autoinc_lock_mode=2
innodb_flush_log_at_trx_commit=0

wsrep_slave_threads=8
wsrep_provider=/usr/lib/libgalera_smm.so
wsrep_provider_options="gcache.size=128M; gcache.page_size=1G"

wsrep_sst_method=xtrabackup
wsrep_sst_auth="clusterrepuser:9be5dfcb-817a-43be-8b1b-ce8cebd1a154"

wsrep_cluster_address="gcomm://10.0.0.4,10.0.0.5"

wsrep_cluster_name=7db3c646-c619-4bfe-b98c-a630e3b20f17
wsrep_node_name=pxc55-work-member-2
wsrep_node_address=10.0.0.4

node1-my.cnf

root@pxc55-work-member-2:/home/ubuntu# cat /etc/mysql/my.cnf /etc/mysql/conf.d/cluster.cnf 
[client]
user            = os_admin
password        = tskFBdzgTrTyQP8bRYzCftKvHwAH2Y3HJFdb
port = 3306

[mysqld_safe]
nice = 0

[mysqld]
user = mysql
port = 3306
basedir = /usr
datadir = /var/lib/mysql
####tmpdir = /tmp
tmpdir = /var/tmp
pid_file = /var/run/mysqld/mysqld.pid
skip-external-locking = 1
key_buffer_size = 50M
max_allowed_packet = 1024K
thread_stack = 192K
thread_cache_size = 4
myisam-recover = BACKUP
query_cache_type = 1
query_cache_limit = 1M
query_cache_size = 8M
innodb_data_file_path = ibdata1:10M:autoextend
innodb_buffer_pool_size = 150M
innodb_file_per_table = 1
innodb_log_files_in_group = 2
innodb_log_file_size=50M
innodb_log_buffer_size=25M
connect_timeout = 15
wait_timeout = 120
join_buffer_size = 1M
read_buffer_size = 512K
read_rnd_buffer_size = 512K
sort_buffer_size = 1M
tmp_table_size = 16M
max_heap_table_size = 16M
table_open_cache = 256
table_definition_cache = 256
open_files_limit = 512
max_user_connections = 100
max_connections = 100
default_storage_engine = innodb
local-infile = 0
server_id = 1517319516

[mysqldump]
quick = 1
quote-names = 1
max_allowed_packet = 16M

[isamchk]
key_buffer = 16M

!includedir /etc/mysql/conf.d/

node2-conf.d.cluster.cnf

[mysqld]
binlog_format=ROW
bind-address=0.0.0.0
default-storage-engine=innodb
innodb_autoinc_lock_mode=2
innodb_flush_log_at_trx_commit=0

wsrep_slave_threads=8
wsrep_provider=/usr/lib/libgalera_smm.so
wsrep_provider_options="gcache.size=128M; gcache.page_size=1G"

wsrep_sst_method=xtrabackup
wsrep_sst_auth="clusterrepuser:9be5dfcb-817a-43be-8b1b-ce8cebd1a154"

wsrep_cluster_address="gcomm://10.0.0.4,10.0.0.5"

wsrep_cluster_name=7db3c646-c619-4bfe-b98c-a630e3b20f17
wsrep_node_name=pxc55-work-member-1
wsrep_node_address=10.0.0.5

node2-my.cnf

root@pxc55-work-member-1:/home/ubuntu# cat /etc/mysql/my.cnf /etc/mysql/conf.d/cluster.cnf 
[client]
user            = os_admin
password        = yZtK4WABxPNwzhKZvWjXbKGUwMx8wKFgfNnM
port = 3306

[mysqld_safe]
nice = 0

[mysqld]
user = mysql
port = 3306
basedir = /usr
datadir = /var/lib/mysql
####tmpdir = /tmp
tmpdir = /var/tmp
pid_file = /var/run/mysqld/mysqld.pid
skip-external-locking = 1
key_buffer_size = 50M
max_allowed_packet = 1024K
thread_stack = 192K
thread_cache_size = 4
myisam-recover = BACKUP
query_cache_type = 1
query_cache_limit = 1M
query_cache_size = 8M
innodb_data_file_path = ibdata1:10M:autoextend
innodb_buffer_pool_size = 150M
innodb_file_per_table = 1
innodb_log_files_in_group = 2
innodb_log_file_size=50M
innodb_log_buffer_size=25M
connect_timeout = 15
wait_timeout = 120
join_buffer_size = 1M
read_buffer_size = 512K
read_rnd_buffer_size = 512K
sort_buffer_size = 1M
tmp_table_size = 16M
max_heap_table_size = 16M
table_open_cache = 256
table_definition_cache = 256
open_files_limit = 512
max_user_connections = 100
max_connections = 100
default_storage_engine = innodb
local-infile = 0
server_id = 455784140

[mysqldump]
quick = 1
quote-names = 1
max_allowed_packet = 16M

[isamchk]
key_buffer = 16M

!includedir /etc/mysql/conf.d/