change mysql data directory ubuntu 17.xx

Follow https://www.digitalocean.com/community/tutorials/how-to-move-a-mysql-data-directory-to-a-new-location-on-ubuntu-16-04
NOTE: you can skip empty directory (/var/lib/mysql/mysql) creation script in ubuntu 17.xx version.

Then try to start mysql server. If fail then log messages are telling you that /usr/sbin/mysqld needs read (r) access to open /proc/14767/status, /sys/devices/system/node/ (trailing slash because it wants to read the directory), and /proc/14767/task/14767/mem. The file to edit is /etc/apparmor.d/usr.sbin.mysqld.

In my case I solved the problem by adding these lines somewhere in the middle (with two spaces in front of each):

/proc/*/status r,
/sys/devices/system/node/ r,
/sys/devices/system/node/** r,

Reload apparmor:

sudo apparmor_parser -r /etc/apparmor.d/usr.sbin.mysqld
sudo /etc/init.d/apparmor reload

After doing that, try starting MySQL, and if you get more errors, add those files too and try again.

In some case mysql may fail to start for assoc i/o error. So, you may need to disable this settings by adding following line into /etc/mysql/mysql.conf.d/mysqld.cnf

innodb_use_native_aio=0

Another note about file permission of data directory is, “mysql” user should have permission into every directory of that path. Like if new data directory is “/media/myusb01/mysql-data” then “mysql” user should read access of “/media” folder and “/media/myusb01” folder and read write access at new data directory.

Hope mysql will start now.

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network adapter at guest [ubuntu] while setup host only network at virtualbox

I’m trying to setup host only network at virtualbox by following http://christophermaier.name/2010/09/01/host-only-networking-with-virtualbox/

but facing to choice network adapter at guest [ubuntu]

To see a list of the adapters your virtual machine can access, use this:

ls /sys/class/net

This will show you the interface names. For example, with two network adapters set up, my Ubuntu guest looks like this.

eth1 eth2 lo

To see a list of active network with IP address assigned

ifconfig

So you can easily guess what network adapter should use for host only network.

Well in a brand new ubuntu machine the permanent network save is not work in the way described in that article. For this you need to install ifupdown or ifupdown2 package

apt install ifupdown2

After install execute following command

ifup eth1

Then reboot.