How to upgrade mongodb online without affecting the normal operation of existing services?

  mongodb, question

Problem description

The version of mongodb online is a bit low, and some grammar is useless. Therefore, I want to upgrade the next version, but I have no previous experience in upgrading the version. I would like to consult relevant experience.

The main problem is that it cannot affect the normal operation of online services.

Each MongoDB version comes with an Upgrade Notes to guide you in upgrading from the previous version to the current version. For example:

After reading these documents carefully, the upgrade process of each version is almost entirely inappropriate, because the three nodes of replica set can be upgraded in turn.
Matters needing attention:

  1. Version upgrade is not allowed. For example, from 2.6 to 4.0, the upgrade path must be: 2.6-> 3.0-> 3.2-> 3.4-> 3.6-> 4.0;
  2. Upgrade the driver before upgrading MongoDB, because the old driver cannot be compatible with the new version, but the new driver can certainly be compatible with the old version.