root@db2:~# apt-get update
...
root@db2:~# apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt-get -f install' to correct these.
The following packages have unmet dependencies:
 mariadb-galera-server-5.5 : Depends: mariadb-server-core-5.5 (>= 5.5.36+maria-1~wheezy) but it is not installed
E: Unmet dependencies. Try using -f.

root@db2:~# dpkg -l | egrep '(mysql|maria)'
ii  libdbd-mysql-perl                4.021-1+b1                    amd64        Perl5 database interface to the MySQL database
ii  libmariadbclient18               5.5.36+maria-1~wheezy         amd64        MariaDB database client library
ii  libmysqlclient18                 5.5.36+maria-1~wheezy         amd64        Virtual package to satisfy external depends
ii  mariadb-client                   5.5.36+maria-1~wheezy         all          MariaDB database client (metapackage depending on the latest version)
ii  mariadb-client-5.5               5.5.36+maria-1~wheezy         amd64        MariaDB database client binaries
ii  mariadb-client-core-5.5          5.5.36+maria-1~wheezy         amd64        MariaDB database core client binaries
ii  mariadb-common                   5.5.36+maria-1~wheezy         all          MariaDB database common files (e.g. /etc/mysql/conf.d/mariadb.cnf)
iU  mariadb-galera-server            5.5.36+maria-1~wheezy         all          MariaDB database server with Galera cluster (metapackage depending on the latest version)
iU  mariadb-galera-server-5.5        5.5.36+maria-1~wheezy         amd64        MariaDB database server with Galera cluster binaries
ii  mysql-common                     5.5.36+maria-1~wheezy         all          MariaDB database common files (e.g. /etc/mysql/my.cnf)

root@db2:~# apt-get remove mariadb-galera-server mariadb-galera-server-5.5
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  galera libaio1 libhtml-template-perl
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  mariadb-galera-server mariadb-galera-server-5.5
0 upgraded, 0 newly installed, 2 to remove and 4 not upgraded.
2 not fully installed or removed.
After this operation, 84.4 MB disk space will be freed.
Do you want to continue [Y/n]? y
(Reading database ... 25139 files and directories currently installed.)
Removing mariadb-galera-server ...
Removing mariadb-galera-server-5.5 ...
Processing triggers for man-db ...

root@db2:~# apt-get install  mariadb-galera-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  mariadb-galera-server-5.5 mariadb-server-core-5.5
Suggested packages:
  tinyca mariadb-test
The following NEW packages will be installed:
  mariadb-galera-server mariadb-galera-server-5.5 mariadb-server-core-5.5
0 upgraded, 3 newly installed, 0 to remove and 4 not upgraded.
Need to get 0 B/30.6 MB of archives.
After this operation, 100 MB of additional disk space will be used.
Do you want to continue [Y/n]? y
Preconfiguring packages ...
(Reading database ... 24971 files and directories currently installed.)
Unpacking mariadb-server-core-5.5 (from .../mariadb-server-core-5.5_5.5.36+maria-1~wheezy_amd64.deb) ...
Selecting previously unselected package mariadb-galera-server-5.5.
Unpacking mariadb-galera-server-5.5 (from .../mariadb-galera-server-5.5_5.5.36+maria-1~wheezy_amd64.deb) ...
[ ok ] Stopping MariaDB database server: mysqld.
dpkg: error processing /var/cache/apt/archives/mariadb-galera-server-5.5_5.5.36+maria-1~wheezy_amd64.deb (--unpack):
 trying to overwrite '/usr/share/man/man8/mysqld.8.gz', which is also in package mariadb-server-core-5.5 5.5.36+maria-1~wheezy
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
Selecting previously unselected package mariadb-galera-server.
Unpacking mariadb-galera-server (from .../mariadb-galera-server_5.5.36+maria-1~wheezy_all.deb) ...
Processing triggers for man-db ...
Errors were encountered while processing:
 /var/cache/apt/archives/mariadb-galera-server-5.5_5.5.36+maria-1~wheezy_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

root@db2:~# apt-get remove mariadb-server-core-5.5
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
 mariadb-galera-server : Depends: mariadb-galera-server-5.5 (= 5.5.36+maria-1~wheezy) but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).