Issue

• Iguana services gets killed/stopped

• The service error log: “Received stop signal“

Cause

• Linux notice Iguana is using a lot of cup or memory, so it stops the Iguana

Background

• The Out Of Memory Killer or OOM Killer is a process that the linux kernel employs when the system is critically low on memory. This situation occurs because the linux kernel has over allocated memory to its processes. When a process starts it requests a block of memory from the kernel. https://neo4j.com/developer/kb/linux-out-of-memory-killer/#:~:text=The%20Out%20Of%20Memory%20Killer,of%20memory%20from%20the%20kernel.

• The OOM score will change over time depending on how much processing the service is doing. Iguana can have a score of 900+ when processing many messages and using a large amount of CPU.

Solutions

• Short Term: One fix for this would be to change the orm_adj to -17 to disable the OOM killer from stopping Iguana

• Long Term: increase the amount of available memory on the server