SolusVM slave connection error happens when you are using Not supported old PHP handler on the slave server after upgrading to the latest SolusVM releases. 

Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to resolve SolusVM errors.

Different solusVM "slave connection error"

While accessing SolusVM Admin control panel users often receive different connection errors related to solusVM slave.

1. Error Retrieving Information Could not contact

You may get an error in your SolusVM Admin control panel like the one below, even if your slave is online:

Error Retrieving Information... Could not contact xxx.xx.xxx.xx on port 6767
413 - Request Entity Too Large

Assuming your slave dedicated server is online and you can SSH into it then there are a few things you can check to see why your Master cannot connect to your slave.

i. Check if you have used all your space.

Use the df -h command inside your slave to check you have not used all of the available space on the / drive.

If you have and it shows as 100% usage you will need to delete some files. This will restore access.

ii. Check if the ID Key and Password Correct

You can check the file /usr/local/solusvm/data/solusvm.conf inside your slave and compare it to your node settings in your SolusVM admin panel. Ensure they match.

Use the below command:

$ cat /usr/local/solusvm/data/solusvm.conf

Also, check if your Master IP listed in /usr/local/solusvm/data/allow.dat if not add the IP of your master to this file and save it.

iii. Check Firewall Blocking Connections

Disable the firewall on both your master and slave to see if this resolves your problem and restores connectivity.

You need to ensure port 6767 is open on both your master and your slave. You can use an iptables rule to open this port.

iv. Check SELinux Status

Check the status of SELinux and if it is enabled disable it. You can check the status of SELinux by issuing:

$ sestatus

If SELinux is enabled you can disable it by editing the /etc/sysconfig/selinux file.

$ nano /etc/sysconfig/selinux

Just change the SELinux=enforcing directive to the one below, save and close the file. It’s a good idea to reboot at this stage:

SELinux=disabled

2. Master SolusVM fails to connect to the slave node

Typically, error message will look as shown below:

Connection Failed
Debug Data: ERROR:4

Nature of this error:

The slave server does not support older PHP handler. The issue can occur after upgrade to the latest SolusVM releases.

To fix this error:

i. Firstly, connect to the slave server via SSH

ii. Then, make php alias to use SolusVM compiled PHP:

# mv /usr/bin/php /usr/bin/backup-php
# ln -s /usr/local/svmstack/php/bin/php /usr/bin/php

iii. Switch from lighttpd to svmstack-nginx service:

a. To Install repository,

# yum install solusvm-release

b. Shutdown lighttpd service,

# service lighttpd stop
# chkconfig lighttpd off

c. Install nginx and legacy configuration file,

# yum install svmstack-nginx svmstack-nginx-legacy-slave-config

d. Start new service,

# service svmstack-nginx restart
# service svmstack-fpm restart

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