src/Riak/Node/Builder.php
public function usingPamAuthentication($user)
    {
        $this->config->setUser($user);
        $this->config->setAuth(true);

        return $this;
    }
public function usingPamAuthentication($user)
    {
        $this->config->setUser($user);
        $this->config->setAuth(true);

        return $this;
    }
usingPamAuthentication

Build nodes with PAM authentication

User authentication and access rules are only available in Riak versions 2 and above. To use this feature, TSL
is required to communicate with your Riak nodes.

@param $user

@return $this