Issues with project export when there isn't a shared directory mount between the front-end and sidekiq

The preprod environment is the only HA environment where we do not have a shared filesystem shared/ that both the front-end and sidekiq can access.

We see the following problem with project-export:

No such file or directory @ rb_sysopen - [FILTERED]

Full error from sidekiq:

{"severity":"WARN","time":"2019-10-04T08:28:47.140Z","message":"Gitlab::ImportExport::Error: No such file or directory @ rb_sysopen - [FILTERED]"}
{"severity":"WARN","time":"2019-10-04T08:28:47.140Z","message":"/opt/gitlab/embedded/service/gitlab-rails/app/services/projects/import_export/export_service.rb:75:in `cleanup_and_notify_error!'\n/opt/gitlab/embedded/service/gitlab-rails/a
pp/services/projects/import_export/export_service.rb:28:in `save_all!'\n/opt/gitlab/embedded/service/gitlab-rails/app/services/projects/import_export/export_service.rb:9:in `execute'\n/opt/gitlab/embedded/service/gitlab-rails/app/workers/
project_export_worker.rb:14:in `perform'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:192:in `execute_job'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:165:
in `block (2 levels) in process'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.rb:128:in `block in invoke'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/metrics/sidekiq_middleware.rb:15:
in `block in call'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/metrics/transaction.rb:57:in `run'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/metrics/sidekiq_middleware.rb:15:in `call'\n/opt/gitlab/embedded/lib/ruby/ge
ms/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.rb:130:in `block in invoke'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/sidekiq_status/server_middleware.rb:7:in `call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/side
kiq-5.2.7/lib/sidekiq/middleware/chain.rb:130:in `block in invoke'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/sidekiq_middleware/instrumentation_logger.rb:7:in `call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7
/lib/sidekiq/middleware/chain.rb:130:in `block in invoke'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/sidekiq_middleware/correlation_logger.rb:10:in `block in call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/gitlab-labkit-0.
5.2/lib/labkit/correlation/correlation_id.rb:18:in `use_id'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/sidekiq_middleware/correlation_logger.rb:9:in `call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sideki
q/middleware/chain.rb:130:in `block in invoke'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/sidekiq_middleware/batch_loader.rb:7:in `call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.
rb:130:in `block in invoke'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/sidekiq_middleware/request_store_middleware.rb:8:in `call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.rb:130:
in `block in invoke'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/sidekiq_middleware/memory_killer.rb:20:in `call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.rb:130:in `block in invo
ke'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/sidekiq_middleware/metrics.rb:23:in `block in call'\n/opt/gitlab/embedded/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/sideki
q_middleware/metrics.rb:22:in `call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.rb:130:in `block in invoke'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sentry-raven-2.9.0/lib/raven/integra
tions/sidekiq.rb:9:in `call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.rb:130:in `block in invoke'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.r
b:133:in `invoke'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:164:in `block in process'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:137:in `block (6 level
s) in dispatch'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/job_retry.rb:109:in `local'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:136:in `block (5 levels) in dispatc
h'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/rails.rb:43:in `block in call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/activesupport-5.2.3/lib/active_support/execution_wrapper.rb:87:in `wrap'\n/opt/gitla
b/embedded/lib/ruby/gems/2.6.0/gems/activesupport-5.2.3/lib/active_support/reloader.rb:73:in `block in wrap'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/activesupport-5.2.3/lib/active_support/execution_wrapper.rb:87:in `wrap'\n/opt/git
lab/embedded/lib/ruby/gems/2.6.0/gems/activesupport-5.2.3/lib/active_support/reloader.rb:72:in `wrap'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/rails.rb:42:in `call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0
/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:132:in `block (4 levels) in dispatch'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:250:in `stats'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq
-5.2.7/lib/sidekiq/processor.rb:127:in `block (3 levels) in dispatch'\n/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/sidekiq_logging/structured_logger.rb:16:in `call'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib
/sidekiq/processor.rb:126:in `block (2 levels) in dispatch'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/job_retry.rb:74:in `global'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/proc
essor.rb:125:in `block in dispatch'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/logging.rb:48:in `with_context'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/logging.rb:42:in `with_j
ob_hash_context'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:124:in `dispatch'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:163:in `process'\n/opt/gitlab/e
mbedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:83:in `process_one'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:71:in `run'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/s
idekiq-5.2.7/lib/sidekiq/util.rb:16:in `watchdog'\n/opt/gitlab/embedded/lib/ruby/gems/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/util.rb:25:in `block in safe_thread'"}