In AWS Lambda, `shm_open("/crac_XXX", O_RDWR | O_CREAT, 0600)` results in
```
shm_open: No such file or directory
```

To support changing env vars, system properties and some JVM flags we need to fallback to an alternative storage, e.g. a file in `/tmp`.

Note that AWS does not let you override env vars for the image (it allows CMD override though, which could alter it through a script).