Thanks for providing all those details @Vardan_Sargsyan92,
The cluster tier - M0 Sandbox (it’s a Dev cluster)
The mongocli index creations are done in a rolling fashion (as is the Atlas API for creating a rolling index). Due to this method of index creation and the current cluster tier in use for your dev environment (M0), the index will not be created as per the Atlas M0 (Free Cluster), M2, and M5 Limitations documentation :
M0free clusters andM2/M5shared clusters do not provide the ability to build indexes with a rolling build.
In saying so, I understand that this behaviour is not expected as an error response to the request or suitable alternative may better indicate the index was not built / being built. I have escalated this internally and was confirmed that this is an issue with mongocli not returning an error when it should.
In the meantime, the index creation command via mongocli that you’ve provided should work as expected if done against a M10+ tier cluster as these tier of clusters do not share the above limitations as the free/shared tier clusters.
Regards,
Jason