Upgrade Guide

There are no special procedures to upgrade a 4.X.X version of DVN to 4.4.0. Since the controller handles database migrations, it should be the first component updated. Then the VTCs hosting session controllers, data deflects, and services. And finally other client VTCs can be updated.

Upgrade order:

Controllers -> Provisioning Tools -> VTCs hosting core components (deflect, session controllers, services) -> All Other VTCs

If you were running 4.2.0 (or prior) versions of the old REST API and old web interface, feel free to stop and uninstall those services. They are no longer needed or used.

NOTE: the 4.4 version of our tools use another global configuration variable called Service Prov URL. If you are deploying and maintaining the provisioning tools for your network, make sure to update that value to the appropriate URL.

MySQL Configuration

The new REST API can take advantage of more concurrent calls than previous versions. MySQL limits the number of concurrent connections. By default, a 5.7 MySQL database has a max limit of 151 max connections.

On a machine with decent resources, this can safely be increased and will allow for better performance of the new REST API.

To check the current setting, run the following from the MySQL CLI:

mysql> SHOW VARIABLES LIKE "max_connections";
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 151   |
+-----------------+-------+
1 row in set (0.00 sec)

To show the number of current connections, you can run:

mysql> SHOW STATUS WHERE `variable_name` = 'Threads_connected';
+-------------------+-------+
| Variable_name     | Value |
+-------------------+-------+
| Threads_connected | 114   |
+-------------------+-------+
1 row in set (0.00 sec)

When loading more intensive pages, the API can use upwards of 50-100 connections. If your current settings don't have enough of a buffer for this, it's suggested to increase the max_connection limit:

Temporarily:

mysql> SET GLOBAL max_connections = 300;

Permanently:

To set this value permanently, edit mysql configuration file on your server and set following variable. The configuration file location may change as per your operating system. By default you can find this at /etc/my.cnf on CentOS and RHEL based system and /etc/mysql/my.cnf on Debian based system.

max_connections = 300