The metric page of SolusVM slave node fails to load statistics: Datastore not found.

Symptoms 

The metric page of the slave node fails to load statistics at SolusVM > Nodes > Metrics:

SVM_ERROR: Datastore not found. Is the hypervisor metrics module installed? It can take 10 minutes for graphs to start to show after installation.

Execution of the back-end tool fails:

# /usr/local/solusvm/Modules/HypervisorMetrics/Hypervisor
PHP Fatal error:
The file /usr/local/solusvm/Modules/HypervisorMetrics/Hypervisor was encoded
with the PHP 5.6 ionCube Encoder and requires PHP 5.6 or PHP 7.0 to be installed.
in Unknown on line 0

Cause

PHP version running on the corresponding node is lower than 5.6:

# php -v
PHP 5.5.38 (cli) (built: Jan 11 2019 14:40:23)

Resolution

1. Connect to the slave server via SSH
2. Switch the PHP to the version from svmstack