voila ce que la commande donne :
dmesg | grep -i mysql | grep -i apparmor
[ 185.746162] audit: type=1400 audit(1527848422.462:44): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/sys/devices/system/node/" pid=4155 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
[ 185.747995] audit: type=1400 audit(1527848422.466:45): apparmor="DENIED" operation="capable" profile="/usr/sbin/mysqld" pid=4155 comm="mysqld" capability=2 capname="dac_read_search"
[ 185.768127] audit: type=1400 audit(1527848422.486:46): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/sys/devices/system/node/" pid=4168 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
[ 190.778700] audit: type=1400 audit(1527848427.493:47): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/sys/devices/system/node/" pid=4200 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
[ 193.584655] audit: type=1400 audit(1527848430.297:48): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/sys/devices/system/node/" pid=4252 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
[ 195.629633] audit: type=1400 audit(1527848432.337:49): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="/usr/sbin/mysqld" pid=4290 comm="apparmor_parser"
[ 196.462607] audit: type=1400 audit(1527848433.177:50): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/sys/devices/system/node/" pid=4353 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
[ 196.483004] audit: type=1400 audit(1527848433.197:51): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/sys/devices/system/node/" pid=4355 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=123 ouid=0
je pense que je vais partir sur maria db si ça ne marche vraiment pas.