mitigate probability of OOM killer of Nodejs nextjs server, set EB2 environment NODE_OPTIONS with --max-old-space-size=<max-reserved in MB>

[tx0c]

Description

the OOM killer happens more often than imagined,

FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory
...

[ec2-user@ip-172-31-7-157 ~]$ time node --trace-warnings -p 'v8.getHeapStatistics()'
{
  total_heap_size: 8155136,
  total_heap_size_executable: 524288,
  total_physical_size: 6561792,
  total_available_size: 2058852536,
  used_heap_size: 4564544,
  heap_size_limit: 2063597568,               <= the default max memory allocation is using 2GB, calculated from 50% of 4GB ;
  malloced_memory: 254104,
  peak_malloced_memory: 476312,
  does_zap_garbage: 0,
  number_of_native_contexts: 1,
  number_of_detached_contexts: 0,
  total_global_handles_size: 8192,
  used_global_handles_size: 2688,
  external_memory: 1984899
}
[ec2-user@ip-172-31-7-157 ~]$ time NODE_OPTIONS="--max_old_space_size=$[1024*3]" node --trace-warnings -p 'v8.getHeapStatistics()'
{
  total_heap_size: 8155136,
  total_heap_size_executable: 524288,
  total_physical_size: 6561792,
  total_available_size: 3266828448,
  used_heap_size: 4548216,
  heap_size_limit: 3271557120,               <= set of 4GB - 1GB reserved = 3GB instead;
  ...

in more logs context: https://www.notion.so/matterslab/2bfadb5c134943cb8203beb069a2280a?v=29efa500e7b74158bb6ab0d872eb14ff

---

Story

• Story: optimization and re-testing developer-resource#420

[tx0c]

and set Scaling triggers on UnhealthyCount instead: ( the original Metric on CPUUtilization 30~80% did not work )

https://stackoverflow.com/a/28849236