1、编辑/etc/gitlab/gitlab.rb文件
### Gravatar Settings
# gitlab_rails[\'gravatar_plain_url\'] = \'http://www.gravatar.com/avatar/%{hash}?s=%{size}&d=identicon\'
gitlab_rails[\'gravatar_plain_url\'] = \'http://cdn.libravatar.org/avatar/%{hash}?s=%{size}&d=identicon\'
# gitlab_rails[\'gravatar_ssl_url\'] = \'https://secure.gravatar.com/avatar/%{hash}?s=%{size}&d=identicon\'
2、重新加载配置
gitlab-ctl reconfigure
参考：https://docs.gitlab.com/13.9/ee/administration/libravatar.html