Random Celery tasks delaying fixed time

Some Celery tasks without any pattern are delaying 10, 20 or 30 seconds.

Seems to me there is a dns resolving timeout of 10 seconds or something similar.

Attaching trace:

[2015-02-26 19:03:03,417: INFO/MainProcess] Task apps.tasks.metrics.update_mp_user[8d4c90da-ef16-4b1e-8f7d-7ca635f8101a] succeeded in 0.412914252001s: None       
[2015-02-26 19:03:13,071: INFO/MainProcess] Task apps.tasks.metrics.update_mp_user[ecc4b268-0917-4172-bdbf-144da5e3d67a] succeeded in 10.112269582s: None         
[2015-02-26 19:03:13,628: INFO/MainProcess] Task apps.tasks.views.remove_fake_attendees[e9cd7bbd-a393-46b2-84b7-652ee3e069cc] succeeded in 10.059868463s: None    
[2015-02-26 19:03:23,970: INFO/MainProcess] Task apps.tasks.views.register_view_plan[fe2b1113-fff9-483e-993b-2a5fadee170b] succeeded in 20.997350218s:                                                                                                                         
[2015-02-26 19:03:24,797: INFO/MainProcess] Task apps.tasks.metrics.update_mp_user[03ba7c4d-6ffa-4991-baa7-f6d71561da8f] succeeded in 11.157462471s: None         
[2015-02-26 19:03:24,798: INFO/MainProcess] Task apps.tasks.views.attend_free_plan[84a45343-9d79-4e2c-af5c-a5d7e17764a0] succeeded in 21.538693966s: True         
[2015-02-26 19:03:34,082: INFO/MainProcess] Task apps.tasks.metrics.update_mp_user[878d982c-5975-4ede-bf5c-e046c516d9db] succeeded in 10.110408876s: None         
[2015-02-26 19:03:34,208: INFO/MainProcess] Task apps.tasks.views.register_view_plan[ae6ff3da-b533-426c-812c-4872d7b085a8] succeeded in 0.125267753s: