Sergey, thanks for review. 
 
The reason is that each temporary docker image is about 5 GB and we don’t have space to keep it localy.
I will update commit message.
  
>Среда, 20 мая 2020, 11:31 +03:00 от Sergey Bronnikov <sergeyb@tarantool.org>:
> 
>Hi, Oleg!
>
>generally LGTM, but see my question regarding commit message.
>
>On 03:36 Wed 20 May , Oleg Piskunov wrote:
>>
>>
>> - add cleanup after perf docker
>>   image preparation (perf_bootstrap job).
>> - cleanup perf docker images on execution hosts
>>   after perf testing (cleanup stage).
>>  
>> Closes #5003
>There is a best practice to explain 'what' and 'why' in a commit message
>body. It is unclear why we should cleanup these images and cannot reuse
>existed images.
>
><snipped>
 
 
--
Oleg Piskunov