Submodules with GitLab CI

Hello!
I get difficulties with the use of submodules in the GitLab CI job. I create a .gitmodules file that contains:

[submodule "MyModule"]
    path = MyModule
    url = ../../usename/MyModule.git

(full path for this repo is git@git.domain.tld:username/MyModule.git)
and add

variables:
  GIT_SUBMODULE_STRATEGY: recursive

to .gitlab-ci.yml file.

Pipeline passed without any errors but MyModule not fetched.

In the log I see

Updating/initializing submodules recursively...

But no repos on the working folder.

I try to add before_script acording to manual:
https://docs.gitlab.com/ee/ci/git_submodules.html#configuring-the-gitmodules-file

But with no luck.

We use self-hosted Gitlab (12.6.1 (a0094541f87) with gitlab-runner (12.9.0).