SymptomsAfter an upgrade attempt, Parallels Plesk Panel (PP) becomes unreachable; psa packages are not upgraded; /usr/local/psa/version remains the same version as before the upgrade attempt; and the version value in the misc table of the psa database shows the old version of PP.
While checking autoinstaller3.log, you can see the following entries:
===> Installing psa database
Trying to start MySQL server... Checking for service MySQL: ..running
Trying to define valid mysql credentials... Trying to establish test connection... ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
Trying to establish test connection... ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
CauseThe cause of the issue could be that the MySQL init script (/etc/init.d/mysql) exits too early from the "start" routine while the server is still in the process of starting; therefore, the upgrade process exits with an error.
ResolutionTo work around this issue, you can add a delay at the end of the "stop" and "start" functions of the mysql script in /etc/init.d/mysql (marked with green):
echo -n "Starting service MySQL "
--datadir=$datadir &>/dev/null &
for((i=0; i<50; i++)); do
test -S $socket && i='' && break
After that, you can re-initiate the upgrade process.
stop) echo -n "Shutting down service MySQL " killproc -p $pid_file -TERM $MYSQLD sleep 10 # Remember status and be verbose rc_status -v ;;