Command entity-updates needs a higher bootstrap level to run I am trying to make drush work on Debian 8 with Drupal 8.

Unluckily, executing drush entity-updates returns the following error messages:


  Command entity-updates needs a higher bootstrap level to run - you will need to invoke drush from a more functional Drupal environment to run this command.
  Command entity-updates requires Drupal core version 8+ to run.
  The drush command 'entity-updates' could not be executed.


drush -vd status executed from .../sites/default returns the following:

.../sites/default# drush -vd status
Starting Drush preflight. [0.04 sec, 2.09 MB]                        [preflight]
Loading drushrc "/etc/drush/drushrc.php" into "system" scope. [0.04  [bootstrap]
sec, 2.09 MB]
Cache MISS cid: 7.1.0-commandfiles-0-81cc86c1995ab7206f383ec28ad43baf    [debug]
[0.09 sec, 2.14 MB]
Cache SET cid: 7.1.0-commandfiles-0-81cc86c1995ab7206f383ec28ad43baf     [debug]
[0.12 sec, 2.16 MB]
Bootstrap to phase 0. [0.53 sec, 6.04 MB]                            [bootstrap]
Found command: core-status (commandfile=core) [0.54 sec, 6.05 MB]    [bootstrap]
Loading outputformat engine. [0.54 sec, 6.06 MB]                        [notice]
Calling hook drush_core_status [0.55 sec, 6.11 MB]                       [debug]
Returned from hook drush_core_status [0.55 sec, 6.11 MB]                 [debug]
 PHP executable         :  /usr/bin/php
 PHP configuration      :  /etc/php5/cli/php.ini
 PHP OS                 :  Linux
 Drush script           :  /root/.composer/vendor/drush/drush/drush.php
 Drush version          :  7.1.0
 Drush temp directory   :  /tmp
 Drush configuration    :  /etc/drush/drushrc.php
 Drush alias files      :

Command dispatch complete [0.63 sec, 6.25 MB]                           [notice]


Running drush sqlc executed from .../sites/default results in:

Unable to load class Drush\Sql\Sql                                   [error]
exception 'Drush\Sql\SqlException' with message 'Unable to find a    [error]
matching SQL Class. Drush cannot find your database connection
details.' in
/root/.composer/vendor/drush/drush/commands/sql/sql.drush.inc:597
Stack trace:
#0
/root/.composer/vendor/drush/drush/commands/sql/sql.drush.inc(454):
drush_sql_get_class()
#1 [internal function]: drush_sql_cli()
#2 /root/.composer/vendor/drush/drush/includes/command.inc(359):
call_user_func_array('drush_sql_cli', Array)
#3 /root/.composer/vendor/drush/drush/includes/command.inc(210):
_drush_invoke_hooks(Array, Array)
#4 [internal function]: drush_command()
#5 /root/.composer/vendor/drush/drush/includes/command.inc(178):
call_user_func_array('drush_command', Array)
#6
/root/.composer/vendor/drush/drush/lib/Drush/Boot/BaseBoot.php(62):
drush_dispatch(Array)
#7 /root/.composer/vendor/drush/drush/drush.php(70):
Drush\Boot\BaseBoot-&gt;bootstrap_and_dispatch()
#8 /root/.composer/vendor/drush/drush/drush.php(11): drush_main()
#9 {main}


I have read other topics but none of the solutions seems work. 

I have installed Drush according to instructions provided here How to install drush 8 properly on Debian 8?.
Same problem here.

In my case I discovered that drush uses native mysql commands, not php lib. Then I've installed by


  apt-get install mysql-client


and works great.

For windows users, I think must install mysql cli commands here.