After updating SolusVM to 1.23.05 or higher the slave nodes are unavailable in UI: Connection Failed Debug Data

Symptoms 

• After updating SolusVM to 1.23.05 or higher the slave nodes are unavailable in UI. The following error is displayed at SolusVM > Nodes > Node:

  SVM_ERROR: Connection Failed Debug Data:

• SolusVM is using PHP not from SolusVM svmstack:

  # php -v
  PHP 5.3.3 (cli) (built: Nov 1 2019 12:28:08)
  Copyright (c) 1997-2010 The PHP Group
  Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies
  with the ionCube PHP Loader v4.2.1, Copyright (c) 2002-2012, by ionCube Ltd.

Cause

Bug with ID #SVM-2773 which is planned to be fixed in future SolusVM updates.

Resolution

1. Connect to affected node via SSH
2. Switch to PHP from SolusVM svmstack using the instruction from this article:
   https://support.solus.io/hc/en-us/articles/360022824452-How-to-switch-old-software-stack-with-Lighttpd-web-server-to-the-latest-one-with-Nginx-on-master-slave-server-
3. Rerun the update with the command:

   # upcp