External Data Services

Stackato comes with several data services that can be enabled on a micro cloud or in a Stackto cluster. However, for implementations where high availability or high performance databases are required, it's advisable to configure Stackato to connect to an externally maintained database or data service.

External data services can be configured at the discretion of the administrator or service provider, but in many cases they can be set up so that Stackato can allocate databases in the same way it does for the built-in databases.

General Principles

Any application running on Stackato can connect to an external database directly as long as the instance can route to the IP address and port of the database server. Database connections can be hard coded in the application without needing to make any changes to Stackato configuration.

To automatically provision databases for applications on these external servers, Stackato must have access to an administrator account on the database server with permissions to create users and databases. The credentials for this account, along with the hostname and port of the database server, are set in the Stackato configuration (via kato config).

MySQL

The MySQL server must be set up to allow connections over the network (rather than just on 'localhost'). Make sure the 'bind-address' is set to the host's IP address (or '0.0.0.0').

Enter the mysql shell and grant the root user privileges on all tables. For example:

$ GRANT ALL PRIVILEGES ON *.* TO 'root'@'10.5.120.%' IDENTIFIED BY
'<PASSWORD>'
WITH GRANT OPTION;
$ FLUSH PRIVILEGES;

The 10.5.120.% portion above should be in relation to the Stackato mysql_node IP address. For increased security you can create a special 'stackato' user with the same privileges as the 'root' user as an alternative option.

Once the user is configured to accept connections from Stackato and to create users and databases, change the configuration for 'mysql_node' in Stackato. For example:

$ kato config set mysql_node mysql/host 10.5.120.101
$ kato config set mysql_node mysql/pass yourpassword
$ kato config set mysql_node mysql/port 3306
$ kato config set mysql_node mysql/user root

Once these have been set, restart mysql:

$ kato restart mysql

PostgreSQL

Make sure the PostgreSQL database server (version 9.1 or later) will accept connections over the network. Edit postgresql.conf make sure the 'listen_addresses' is uncommented and set to the networked interface IP. For example:

listen_addresses = 'localhost, 10.5.120.102'

Edit pg_hba.conf and make sure a line exists that allows all Stackato instances to connect to it. For example:

host    all   all       10.5.120.0/23   md5

Restart PostgreSQL.

Using the default 'postgres' user (or another account with the same superuser privileges), change the configuration for 'postgresql_node' in Stackato. For example:

$ kato config set postgresql_node postgresql/host 10.5.120.102
$ kato config set postgresql_node postgresql/pass yourpassword
$ kato config set postgresql_node postgresql/port 5432
$ kato config set postgresql_node postgresql/user postgres

Once these have been set, restart the postgresql_node process:

$ kato restart postgresql_node

Troubleshooting

The psql and mysql clients are available at the command line on the Stackato VM. Log in to the Core node (i.e. the one running the Cloud Controller) and test the database connection directly with the appropriate client. For example:

$ mysql -u stackato -p mypassword -h 10.5.120.101
mysql> show databases;
...

If the basic client connection works, test database creation using the stackato create-service ... command:

$ stackato create-service mysql
Creating Service [mysql-24901]: OK

If there are problems, check the corresponding logs on the database server. These are generally found in /var/log/postgresql and /var/log/mysql.

Logs from Stackato can be viewed with kato log tail:

$ kato log tail postgresql_node