Galera library is not installable from MariaDB deb repositories on Wheezy
$ sudo apt-get install galera
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
galera : Depends: libssl0.9.8 but it is not installable
E: Unable to correct problems, you have held broken packages.
Wheezy contains libssl1.0.0, there is no installation candidate for 0.9.8.
I've set it to Minor because, as I understand, Wheezy is not yet a stable release.