SQL Node not connected in a mysql cluster - mysql

Question

I am trying to deploy a mysql cluster (4 machines) with 1 node manager, 1 sql node, and 2 data nodes. I am following these tutorials which are complimentary (first part, second part, third part, fourth part) from the official mysql website. However I have a problem with the SQL Node which is always not connected, as you can see here in the node manager:
$ sudo ndb_mgm -e show
Connected to Management Server at: localhost:1186
Cluster Configuration
---------------------
[ndbd(NDB)] 2 node(s)
id=2 #10.31.35.40 (mysql-5.6.23 ndb-7.4.5, starting, Nodegroup: 0)
id=3 #10.31.35.42 (mysql-5.6.23 ndb-7.4.5, starting, Nodegroup: 0)
[ndb_mgmd(MGM)] 1 node(s)
id=1 #10.31.37.108 (mysql-5.6.23 ndb-7.4.5)
[mysqld(API)] 1 node(s)
id=4 (not connected, accepting connect from 10.31.35.41)
I don't know why the SQL node is not connected to the management node !! I looked for similar problems in google but I still can't resolve my problem !
I tried several times to do:
/etc/init.d/mysql.server stop
and
/etc/init.d/mysql.server start
but in vain.
Here is also the output of mysqld in verbose mode which mentions a problem I don't know what its cause:
ubuntu#10-31-35-41:/usr/local/mysql/bin$ sudo mysqld --verbose --help
150404 5:26:00 [Note] Plugin 'FEDERATED' is disabled.
150404 5:26:00 [ERROR] mysqld: unknown option '--ndbcluster'
......
Also when I try to see the location of the mysqld_safe (which I think is not normal since as you can see in the first part of the tutorial the folder was put in /usr/local/mysql (and I am supposed to use the mysql.server, isn't it ?)), I have
$ which mysqld_safe
/usr/bin/mysqld_safe
Moreover, I don't know if there is a conflict with the previous installed package of mysql
This is /etc/mysql/my.cnf (in the sql node, which is the same in the working data nodes):
[mysqld]
# Options for mysqld process:
ndbcluster # run NDB storage engine
[mysql_cluster]
# Options for MySQL Cluster processes:
ndb-connectstring=10.31.37.108 # location of management server
This is the config.ini file in the ndb_mgm:
[ndbd default]
# Options affecting ndbd processes on all data nodes:
NoOfReplicas=2 # Number of replicas
DataMemory=80M # How much memory to allocate for data storage
IndexMemory=18M # How much memory to allocate for index storage
# For DataMemory and IndexMemory, we have used the
# default values. Since the "world" database takes up
# only about 500KB, this should be more than enough for
# this example Cluster setup.
[tcp default]
# TCP/IP options:
portnumber=2202 # This the default; however, you can use any
# port that is free for all the hosts in the cluster
# Note: It is recommended that you do not specify the port
# number at all and simply allow the default value to be used
# instead
[ndb_mgmd]
# Management process options:
hostname=10.31.37.108 # Hostname or IP address of MGM node
datadir=/var/lib/mysql-cluster # Directory for MGM node log files
[ndbd]
# Options for data node "A":
# (one [ndbd] section per data node)
hostname=10.31.35.40 # Hostname or IP address
datadir=/usr/local/mysql/data # Directory for this data node's data files
[ndbd]
# Options for data node "B":
hostname=10.31.35.42 # Hostname or IP address
datadir=/usr/local/mysql/data # Directory for this data node's data files
[mysqld]
# SQL node options:
hostname=10.31.35.41 # Hostname or IP address
# (additional mysqld connections can be
# specified for this node for various
# purposes such as running ndb_restore)
Thank you very much in advance for your help !!

Answer 1

To resolve the problem I changed the permissions on the /usr/local/mysql/data directory as follows:
sudo chown -R ubuntu data/
so now instead of:
$ /usr/local/mysql/support-files/mysql.server restart
* MySQL server PID file could not be found!
Starting MySQL
. * The server quit without updating PID file (/usr/local/mysql/data/ip-172-31-46-103.pid).
I get now:
$ /usr/local/mysql/support-files/mysql.server restart
Shutting down MySQL
.. *
Starting MySQL
. *