MySQL login-path issues with clustercheck script used in xinetd - mysql

Question

default: on
# description: mysqlchk
service mysqlchk
{
# this is a config for xinetd, place it in /etc/xinetd.d/
disable = no
flags = REUSE
socket_type = stream
type = UNLISTED
port = 9200
wait = no
user = root
server = /usr/bin/mysqlclustercheck
log_on_failure += USERID
only_from = 0.0.0.0/0
#
# Passing arguments to clustercheck
# <user> <pass> <available_when_donor=0|1> <log_file> <available_when_readonly=0|1> <defaults_extra_file>"
# Recommended: server_args = user pass 1 /var/log/log-file 0 /etc/my.cnf.local"
# Compatibility: server_args = user pass 1 /var/log/log-file 1 /etc/my.cnf.local"
# 55-to-56 upgrade: server_args = user pass 1 /var/log/log-file 0 /etc/my.cnf.extra"
#
# recommended to put the IPs that need
# to connect exclusively (security purposes)
per_source = UNLIMITED
}
/etc/xinetd.d #
It is kind of strange that script works fine when run manually when it runs using /etc/xinetd.d/ , it is not working as expected.
In mysqlclustercheck script, instead of using --user= and passord= syntax, I am using --login-path= syntax
script runs fine when I run using command line but status for xinetd was showing signal 13. After debugging, I have found that even simple command like this is not working
mysql_config_editor print --all >>/tmp/test.txt
We don't see any output generated when it is run using xinetd ( mysqlclustercheck)

Answer 1

Have you tried the following instead of /usr/bin/mysqlclustercheck?
server = /usr/bin/clustercheck
I am wondering if you could test your binary location with the linux which command.

Answer 2

A long time ago since this question was asked, but it just came to my attention.
First of all as mentioned, Percona Cluster Control script is called clustercheck, so make sure you are using the correct name and correct path.
Secondly, since the server script runs fine from command line, it seems to me that the path of mysql client command is not known by the xinetd when it runs the Cluster Control script.
Since the mysqlclustercheck script as it is offered from Percona, it uses only the binary name mysql without specifying the absolute path I suggest you do the following:
Find where mysql client command is located on your system:
ccloud#gal1:~> sudo -i
gal1:~ # which mysql
/usr/local/mysql/bin/mysql
gal1:~ #
then edit script /usr/bin/mysqlclustercheck and in the following line:
MYSQL_CMDLINE="mysql --defaults-extra-file=$DEFAULTS_EXTRA_FILE -nNE --connect-timeout=$TIMEOUT \
place the exact path of mysql client command you found in the previous step.
I also see that you are not using MySQL connection credentials for connecting to MySQL server. mysqlclustercheck script as it is offered from Percona, it uses User/Password in order to connect to MySQL server.
So normally, you should execute the script in the command line like:
gal1:~ # /usr/sbin/clustercheck haproxy haproxyMySQLpass
HTTP/1.1 200 OK
Content-Type: text/plain
Where haproxy/haproxyMySQLpass is the MySQL connection user/pass for HAProxy monitoring user.
Additionally, you should specify them to your script's xinetd settings like:
server = /usr/bin/mysqlclustercheck
server_args = haproxy haproxyMySQLpass
Last but not least, the signal 13 you are getting is because you try to write something in a script run by xinetd. If for example in your mysqlclustercheck you try to add a statement like
echo "debug message"
you probably going to see the broken pipe signal (13 in POSIX).
Finally, I had issues with this script using SLES 12.3 and I finally manage to run it not as 'nobody' but as 'root'.
Hope it helps