Re: 8.0.15 to 8.0.16 upgrade fails due to permissions on Ubuntu

[Terje Røsten]

- Could not create server upgrade info file at '/var/lib/mysql/'

This is this bug:
https://bugs.mysql.com/bug.php?id=95165

Workaround:

sudo chown mysql:mysql /var/lib/mysql/mysql_upgrade_info

- Can't find error-message file '/usr/share/mysql/errmsg.sys'

This is due to incorrect basedir or/and lc-messages-dir option in
my.cnf.

- Fix:
Remove any basedir and lc-message-dir options in my,cnf

- The SSL library function CRYPTO_set_mem_functions failed.

MySQL is now using system SSL libs. Make sure these are updated:

$ yum update openssl

Verify mysqld uses this libs

$ ldd /usr/sbin/mysqld|grep ssl
libssl.so.10 => /lib64/libssl.so.10 (0x00007f0869a83000)

$ rpm -qf /lib64/libssl.so.10
openssl-libs-1.0.2k-16.el7_6.1.x86_64

- and other paths broken (from mysql to mysql-8.0)

Can you post your my.cnf file to better identify the issues?