don't rely on configuration for critical options, add --daemonize no in unit file

redis.init

@@ -9,7 +9,7 @@
 . /etc/rc.d/init.d/functions
 
 name="redis-server"
-exec="/usr/sbin/$name"
+exec="/usr/bin/$name"
 pidfile="/var/run/redis/redis.pid"
 REDIS_CONFIG="/etc/redis.conf"
 
@@ -21,7 +21,7 @@ start() {
     [ -f $REDIS_CONFIG ] || exit 6
     [ -x $exec ] || exit 5
     echo -n $"Starting $name: "
-    daemon --user ${REDIS_USER-redis} "$exec $REDIS_CONFIG"
+    daemon --user ${REDIS_USER-redis} "$exec $REDIS_CONFIG --daemonize yes --pidfile $pidfile"
     retval=$?
     echo
     [ $retval -eq 0 ] && touch $lockfile

redis.service

@@ -3,7 +3,7 @@ Description=Redis persistent key-value database
 After=network.target
 
 [Service]
-ExecStart=/usr/bin/redis-server /etc/redis.conf
+ExecStart=/usr/bin/redis-server /etc/redis.conf --daemonize no
 User=redis
 Group=redis