docker: Create data_dir if it does not exist
docker: Create data_dir if it does not exist

When provisioning a Scylla docker image with --developer-mode 0 (disabled)
scylla_raid_setup is not invoked. As a consequence the "data" directory is not
created and scylla_io_setup fails (steps to reproduce and error message provided
at the end).

This patch adds the same verifications present in scylla_io_setup to docker's
scyllasetup.py and creates the data directory in the case it is not present.

--

Steps to reproduce on AWS i3.2xlarge with Ubuntu 16.04:

sudo -s
apt update && apt upgrade -y && apt-get install docker.io -y

mdadm --create --verbose --force --run /dev/md0 --level=0 -c1024 --raid-devices=1 /dev/nvme0n1
mkfs.xfs /dev/md0 -f -K
mkdir /var/lib/scylla
mount -t xfs /dev/md0 /var/lib/scylla

docker run --name some-scylla \
  --volume /var/lib/scylla:/var/lib/scylla \
  -p 9042:9042 -p 7000:7000 -p 7001:7001 -p 7199:7199 \
  -p 9160:9160 -p 9180:9180 -p 10000:10000 \
  -d scylladb/scylla --overprovisioned 1 --developer-mode 0

docker logs some-scylla
  running: (['/usr/lib/scylla/scylla_dev_mode_setup', '--developer-mode', '0'],)
  running: (['/usr/lib/scylla/scylla_io_setup'],)
  terminate called after throwing an instance of 'std::system_error'
    what():  open: No such file or directory
  ERROR:root:/var/lib/scylla/data did not pass validation tests, it may not be on XFS and/or has limited disk space.
  This is a non-supported setup, and performance is expected to be very bad.
  For better performance, placing your data on XFS-formatted directories is required.
  To override this error, enable developer mode as follow:
  sudo /usr/lib/scylla/scylla_dev_mode_setup --developer-mode 1
  failed!
  Traceback (most recent call last):
    File "/docker-entrypoint.py", line 15, in <module>
      setup.io()
    File "/scyllasetup.py", line 34, in io
      self._run(['/usr/lib/scylla/scylla_io_setup'])
    File "/scyllasetup.py", line 23, in _run
      subprocess.check_call(*args, **kwargs)
    File "/usr/lib64/python3.4/subprocess.py", line 558, in check_call
      raise CalledProcessError(retcode, cmd)
  subprocess.CalledProcessError: Command '['/usr/lib/scylla/scylla_io_setup']' returned non-zero exit status 1

ls -latr /var/lib/scylla
  total 4
  drwxr-xr-x 44 root root 4096 Abr 24 13:02 ..
  drwxr-xr-x  2 root root    6 Abr 24 13:10 .

Signed-off-by: Moreno Garcia <1c018a305664da4040a64de20321707c068d2f4a@scylladb.com>
Message-Id: <20180424173729.22151-1-1c018a305664da4040a64de20321707c068d2f4a@scylladb.com>

duarten/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla