Slave nodes unavailable in SolusVM UI: Request Entity Too Large

Symptoms 

• Slave nodes unavailable in SolusVM UI at SolusVM > Nodes > Node:

  SVM_ERROR: Connection failed
  413 - Request Entity Too Large

Cause

No free space left on / partition on Master node:

# df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/sda3   77G  77G     0 100% /

Resolution

Free up or extend the disk space on / partition on Master node.