def _check_tmp_free_space() -> CheckLevels:
"""
Warn if there is not enough free space in the default temporary directory.
"""
free_space = shutil.disk_usage(gettempdir()).free
free_space_gb = free_space / 1024 / 1024 / 1024
low_space_message = (
'The default temporary directory ("{tmp_prefix}") has '
'{free_space:.1f} GB of free space available. '
'Creating a cluster typically takes approximately 2 GB of temporary '
'storage. '
'If you encounter problems with disk space usage, set the ``TMPDIR`` '
'environment variable to a suitable temporary directory or use the '
'``--workspace-dir`` option on the ``dcos-docker create`` command.'
).format(
tmp_prefix=Path('/') / gettempprefix(),
free_space=free_space_gb,
)
if free_space_gb < 5:
warn(message=low_space_message)
return CheckLevels.WARNING
return CheckLevels.NONE
def _check_storage_driver() -> CheckLevels:
"""
Warn if the Docker storage driver is not a recommended driver.
"""
client = docker_client()
host_driver = client.info()['Driver']
storage_driver_url = (
'https://docs.docker.com/storage/storagedriver/select-storage-driver/')
# Any image will do, we use this for another test so using it here saves
# pulling another image.
tiny_image = 'luca3m/sleep'
container = client.containers.run(
image=tiny_image,
tty=True,
detach=True,
privileged=True,
volumes={'/proc': {
'bind': '/host/proc',
'mode': 'rw',
}},
)
cmd = ['cat', '/host/proc/filesystems']
_, output = container.exec_run(cmd=cmd)
container.stop()
container.remove(v=True)
aufs_supported = bool(b'aufs' in output.split())
supported_host_driver = bool(host_driver in DOCKER_STORAGE_DRIVERS)
can_work = bool(aufs_supported or supported_host_driver)
if not can_work:
message = (
"The host's Docker storage driver is \"{host_driver}\". "
'aufs is not available. '
'Change your storage driver to one of: {supported_drivers}. '
'Alternatively try using the `--docker-storage-driver` option '
'with `overlay` or `overlay2`. '
'See {help_url}.').format(
host_driver=host_driver,
supported_drivers=', '.join(
sorted(DOCKER_STORAGE_DRIVERS.keys())),
help_url=storage_driver_url,
)
error(message=message)
return CheckLevels.ERROR
if not supported_host_driver:
message = ("The host's Docker storage driver is \"{host_driver}\". "
'We recommend that you use one of: {supported_drivers}. '
'See {help_url}.').format(
host_driver=host_driver,
supported_drivers=', '.join(
sorted(DOCKER_STORAGE_DRIVERS.keys())),
help_url=storage_driver_url,
)
warn(message=message)
return CheckLevels.WARNING
return CheckLevels.NONE
def _check_can_mount_in_docker() -> CheckLevels:
"""
Check for an incompatibility between some systemd versions and some
versions of Docker.
"""
docker_client()
cluster_backend = Docker(docker_version=DockerVersion.v1_13_1)
args = ['docker', 'run', '-v', '/foo', 'alpine']
error_message_substring = 'no subsystem for mount'
with Cluster(cluster_backend=cluster_backend) as cluster:
(public_agent, ) = cluster.public_agents
try:
public_agent.run(args=args)
except subprocess.CalledProcessError as exc:
if error_message_substring not in exc.stderr.decode():
raise
message = (
'An issue has been detected which means that, for some '
'versions of Docker inside DC/OS nodes, it will not be '
'possible to create containers with mounts. '
'Some functionality may be affected by this, for example '
'extracting the DC/OS installer on a node.'
'\n'
'This issue is likely because the host\'s version of systemd '
'is greater than version 232, which causes the following '
'known issue: '
'https://github.com/opencontainers/runc/issues/1175.'
'\n'
'Newer versions of Docker, work well with new versions of '
'systemd. '
'To avoid issues caused by this incompatibility, do one of '
'the following:'
'\n* Set ``systemd.legacy_systemd_cgroup_controller=yes`` as '
'a kernel parameter on your host.'
'\n* Use versions of Docker newer than 1.13.1 inside the '
'DC/OS nodes.'
' To do this in the ``dcos-docker`` CLI, use the '
'``--docker-version`` option on ``dcos-docker create``.'
' To do this in the Python library, pass a '
'``docker_version`` parameter to the ``Docker`` backend class.'
)
warn(message=message)
return CheckLevels.WARNING
return CheckLevels.NONE
def check_docker() -> CheckLevels:
"""
Error if Docker is not running.
"""
try:
docker.from_env(version='auto')
except docker.errors.DockerException:
message = (
'Docker is not running. '
'Docker is required for the "create" command to determine the '
'DC/OS variant of the given DC/OS artifact. '
'Use the "--variant" option when using the "create" command or '
'install and run Docker.'
)
warn(message=message)
return CheckLevels.WARNING
return CheckLevels.NONE
def _check_networking() -> CheckLevels:
"""
Error if the Docker network is not set up correctly.
"""
highest_level = CheckLevels.NONE
# Image for a container which sleeps for a long time.
tiny_image = 'luca3m/sleep'
client = docker_client()
docker_for_mac = bool(client.info()['OperatingSystem'] == 'Docker for Mac')
ping_container = client.containers.run(
image=tiny_image,
tty=True,
detach=True,
)
ping_container.reload()
ip_address = ping_container.attrs['NetworkSettings']['IPAddress']
try:
subprocess.check_call(
args=['ping', ip_address, '-c', '1', '-t', '1'],
stdout=subprocess.DEVNULL,
stderr=subprocess.DEVNULL,
)
except subprocess.CalledProcessError:
message = (
'Cannot connect to a Docker container by its IP address. '
'This is needed for features such as connecting to the web UI and '
'using the DC/OS CLI. '
'To use the "wait" command without resolving this issue, use the '
'"--skip-http-checks" flag on the "wait" command.'
)
if docker_for_mac:
message += (
' '
'We recommend using "dcos-docker setup-mac-network" to '
'resolve this issue.'
)
warn(message=message)
highest_level = CheckLevels.WARNING
ping_container.stop()
ping_container.remove(v=True)
return highest_level
def _check_docker_root_free_space() -> CheckLevels:
"""
Warn if there is not enough free space in the Docker root directory.
"""
# Any image will do, we use this for another test so using it here saves
# pulling another image.
tiny_image = 'luca3m/sleep'
client = docker_client()
container = client.containers.run(
image=tiny_image,
tty=True,
detach=True,
privileged=True,
)
cmd = ['df', '/']
_, output = container.exec_run(cmd=cmd)
container.stop()
container.remove(v=True)
output_lines = output.decode().strip().split('\n')
# We skip the first line which is headers.
# Sometimes the information is split across multiple lines.
information = ' '.join(line for line in output_lines[1:])
_, _, _, avail, _, _ = information.split()
available_bytes = int(avail)
available_gigabytes = available_bytes / 1024 / 1024
low_space_message = (
'The Docker root directory is at "{docker_root_dir}". '
'On macOS this location is on a hidden virtual machine. '
'This directory has {free_space:.1f} GB of free space available. '
'If you encounter problems try running ``docker volume prune``.'
).format(
docker_root_dir=client.info()['DockerRootDir'],
free_space=available_gigabytes,
)
# The choice of 5 GB is arbitrary. Let's see how it goes in practice and
# potentially adjust later.
if available_gigabytes < 5:
warn(message=low_space_message)
return CheckLevels.WARNING
return CheckLevels.NONE