Illegal instruction (core dumped) mongod --fork --port 27017 --dbpath "$MONGO_DB_PATH"

As most of you know, Appsmith released a checkpoint version with v1.9.2 (release notes) with significant changes.

TLDR; with v1.9.2+ Appsmith only supports MongoDB v5.0

Although, MongoDB v5 itself comes with it’s own limitations, mainly - MongoDB v5.0 requires CPU AVX instructions, which is causing you to get above error.

Solutions -
There are two types of self-hosted deployments one can have -

  1. Instance with embedded MongoDB
  2. Instance with custom MongoDB

1. For users who are using the embedded MongoDB (i.e. default mongo db that is shipped with Appsmith).

Here you have three options -
a. Migrate your setup to a new server that can run mongo v5. Here is the list of suggested platforms
b. Start using a custom mongoDB so that your Appsmith instance can stay on the same server but DB is migrated
c. Downgrade your instance back to v1.8.15 and keep using it until you are ready to migrate as suggested in the first option.

2. For users who are using the custom MongoDB (i.e using their own mongo server to manage the data)

You also have two options -
a. Migrate your mongo server to use mongoDB v5 on a compliant hardware (Here is the list of suggested platforms)
b. Downgrade your instance back to v1.8.15 and keep using it until you are ready to migrate as suggested in previous option.