As we can't control which allocations are destroyed when downscaling a job, we decided
to use Nomad jobs as our runners. Thus for each runner we prewarm for an environment,
a corresponding job is created in Nomad. We create a default job that serves as a template
for the runners. Using this, already existing execution environments can easily be restored,
once Poseidon is restarted.
Previously, the network_mode was only set when creating a job with
network_access = false. This results in Nomad leaving this setting
as is when updating the job to use network. Thus a job would have
had the mapped ports in the Nomad UI, but the Docker network_mode
would still be 'none'.
This enables executing commands in runners and forwarding input and
output between the runner and the websocket to the client.
Co-authored-by: Maximilian Paß <maximilian.pass@student.hpi.uni-potsdam.de>
