path: root/resources/libraries/python/ContainerUtils.py

# Copyright (c) 2018 Cisco and/or its affiliates.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Bug workaround in pylint for abstract classes.
# pylint: disable=W0223

"""Library to manipulate Containers."""

from collections import OrderedDict, Counter

from resources.libraries.python.ssh import SSH
from resources.libraries.python.constants import Constants
from resources.libraries.python.CpuUtils import CpuUtils
from resources.libraries.python.topology import Topology
from resources.libraries.python.VppConfigGenerator import VppConfigGenerator


__all__ = ["ContainerManager", "ContainerEngine", "LXC", "Docker", "Container"]

SUPERVISOR_CONF = '/etc/supervisord.conf'


class ContainerManager(object):
    """Container lifecycle management class."""

    def __init__(self, engine):
        """Initialize Container Manager class.

        :param engine: Container technology used (LXC/Docker/...).
        :type engine: str
        :raises NotImplementedError: If container technology is not implemented.
        """
        try:
            self.engine = globals()[engine]()
        except KeyError:
            raise NotImplementedError('{engine} is not implemented.'.
                                      format(engine=engine))
        self.containers = OrderedDict()

    def get_container_by_name(self, name):
        """Get container instance.

        :param name: Container name.
        :type name: str
        :returns: Container instance.
        :rtype: Container
        :raises RuntimeError: If failed to get container with name.
        """
        try:
            return self.containers[name]
        except KeyError:
            raise RuntimeError('Failed to get container with name: {name}'.
                               format(name=name))

    def construct_container(self, **kwargs):
        """Construct container object on node with specified parameters.

        :param kwargs: Key-value pairs used to construct container.
        :param kwargs: dict
        """
        # Create base class
        self.engine.initialize()
        # Set parameters
        for key in kwargs:
            setattr(self.engine.container, key, kwargs[key])

        # Set additional environmental variables
        setattr(self.engine.container, 'env',
                'MICROSERVICE_LABEL={label}'.format(label=kwargs['name']))

        # Set cpuset.cpus cgroup
        skip_cnt = kwargs['cpu_skip']
        smt_used = CpuUtils.is_smt_enabled(kwargs['node']['cpuinfo'])
        if not kwargs['cpu_shared']:
            skip_cnt += kwargs['i'] * kwargs['cpu_count']
        self.engine.container.cpuset_cpus = \
            CpuUtils.cpu_slice_of_list_per_node(node=kwargs['node'],
                                                cpu_node=kwargs['cpuset_mems'],
                                                skip_cnt=skip_cnt,
                                                cpu_cnt=1,
                                                smt_used=False) \
            + \
            CpuUtils.cpu_slice_of_list_per_node(node=kwargs['node'],
                                                cpu_node=kwargs['cpuset_mems'],
                                                skip_cnt=skip_cnt+1,
                                                cpu_cnt=kwargs['cpu_count']-1,
                                                smt_used=smt_used)

        # Store container instance
        self.containers[kwargs['name']] = self.engine.container

    def construct_containers(self, **kwargs):
        """Construct 1..N container(s) on node with specified name.

        Ordinal number is automatically added to the name of container as
        suffix.

        :param kwargs: Named parameters.
        :param kwargs: dict
        """
        name = kwargs['name']
        for i in range(kwargs['count']):
            # Name will contain ordinal suffix
            kwargs['name'] = ''.join([name, str(i+1)])
            # Create container
            self.construct_container(i=i, **kwargs)

    def acquire_all_containers(self):
        """Acquire all containers."""
        for container in self.containers:
            self.engine.container = self.containers[container]
            self.engine.acquire()

    def build_all_containers(self):
        """Build all containers."""
        for container in self.containers:
            self.engine.container = self.containers[container]
            self.engine.build()

    def create_all_containers(self):
        """Create all containers."""
        for container in self.containers:
            self.engine.container = self.containers[container]
            self.engine.create()

    def execute_on_container(self, name, command):
        """Execute command on container with name.

        :param name: Container name.
        :param command: Command to execute.
        :type name: str
        :type command: str
        """
        self.engine.container = self.get_container_by_name(name)
        self.engine.execute(command)

    def execute_on_all_containers(self, command):
        """Execute command on all containers.

        :param command: Command to execute.
        :type command: str
        """
        for container in self.containers:
            self.engine.container = self.containers[container]
            self.engine.execute(command)

    def install_vpp_in_all_containers(self):
        """Install VPP into all containers."""
        for container in self.containers:
            self.engine.container = self.containers[container]
            # We need to install supervisor client/server system to control VPP
            # as a service
            self.engine.install_supervisor()
            self.engine.install_vpp()
            self.engine.restart_vpp()

    def restart_vpp_in_all_containers(self):
        """Restart VPP on all containers."""
        for container in self.containers:
            self.engine.container = self.containers[container]
            self.engine.restart_vpp()

    def configure_vpp_in_all_containers(self, chain_topology,
                                        dut1_if=None, dut2_if=None):
        """Configure VPP in all containers.

        :param chain_topology: Topology used for chaining containers can be
            chain or cross_horiz. Chain topology is using 1 memif pair per
            container. Cross_horiz topology is using 1 memif and 1 physical
            interface in container (only single container can be configured).
        :param dut1_if: Interface on DUT1 directly connected to DUT2.
        :param dut2_if: Interface on DUT2 directly connected to DUT1.
        :type container_topology: str
        :type dut1_if: str
        :type dut2_if: str
        """
        # Count number of DUTs based on node's host information
        dut_cnt = len(Counter([self.containers[container].node['host']
                               for container in self.containers]))
        mod = len(self.containers)/dut_cnt
        container_vat_template = 'memif_create_{topology}.vat'.format(
            topology=chain_topology)

        if chain_topology == 'chain':
            for i, container in enumerate(self.containers):
                mid1 = i % mod + 1
                mid2 = i % mod + 1
                sid1 = i % mod * 2 + 1
                sid2 = i % mod * 2 + 2
                self.engine.container = self.containers[container]
                self.engine.create_vpp_startup_config()
                self.engine.create_vpp_exec_config(container_vat_template, \
                    mid1=mid1, mid2=mid2, sid1=sid1, sid2=sid2, \
                    socket1='memif-{c.name}-{sid}'. \
                    format(c=self.engine.container, sid=sid1), \
                    socket2='memif-{c.name}-{sid}'. \
                    format(c=self.engine.container, sid=sid2))
        elif chain_topology == 'cross_horiz':
            if mod > 1:
                raise RuntimeError('Container chain topology {topology} '
                                   'supports only single container.'.
                                   format(topology=chain_topology))
            for i, container in enumerate(self.containers):
                mid1 = i % mod + 1
                sid1 = i % mod * 2 + 1
                self.engine.container = self.containers[container]
                if 'DUT1' in self.engine.container.name:
                    if_pci = Topology.get_interface_pci_addr( \
                        self.engine.container.node, dut1_if)
                    if_name = Topology.get_interface_name( \
                        self.engine.container.node, dut1_if)
                if 'DUT2' in self.engine.container.name:
                    if_pci = Topology.get_interface_pci_addr( \
                        self.engine.container.node, dut2_if)
                    if_name = Topology.get_interface_name( \
                        self.engine.container.node, dut2_if)
                self.engine.create_vpp_startup_config_dpdk_dev(if_pci)
                self.engine.create_vpp_exec_config(container_vat_template, \
                    mid1=mid1, sid1=sid1, if_name=if_name, \
                    socket1='memif-{c.name}-{sid}'. \
                    format(c=self.engine.container, sid=sid1))
        else:
            raise RuntimeError('Container topology {topology} not implemented'.
                               format(topology=chain_topology))

    def stop_all_containers(self):
        """Stop all containers."""
        for container in self.containers:
            self.engine.container = self.containers[container]
            self.engine.stop()

    def destroy_all_containers(self):
        """Destroy all containers."""
        for container in self.containers:
            self.engine.container = self.containers[container]
            self.engine.destroy()


class ContainerEngine(object):
    """Abstract class for container engine."""

    def __init__(self):
        """Init ContainerEngine object."""
        self.container = None

    def initialize(self):
        """Initialize container object."""
        self.container = Container()

    def acquire(self, force):
        """Acquire/download container.

        :param force: Destroy a container if exists and create.
        :type force: bool
        """
        raise NotImplementedError

    def build(self):
        """Build container (compile)."""
        raise NotImplementedError

    def create(self):
        """Create/deploy container."""
        raise NotImplementedError

    def execute(self, command):
        """Execute process inside container.

        :param command: Command to run inside container.
        :type command: str
        """
        raise NotImplementedError

    def stop(self):
        """Stop container."""
        raise NotImplementedError

    def destroy(self):
        """Destroy/remove container."""
        raise NotImplementedError

    def info(self):
        """Info about container."""
        raise NotImplementedError

    def system_info(self):
        """System info."""
        raise NotImplementedError

    def install_supervisor(self):
        """Install supervisord inside a container."""
        self.execute('sleep 3')
        self.execute('apt-get update')
        self.execute('apt-get install -y supervisor')
        self.execute('echo "{config}" > {config_file}'.
                     format(
                         config='[unix_http_server]\n'
                         'file  = /tmp/supervisor.sock\n\n'
                         '[rpcinterface:supervisor]\n'
                         'supervisor.rpcinterface_factory = '
                         'supervisor.rpcinterface:make_main_rpcinterface\n\n'
                         '[supervisorctl]\n'
                         'serverurl = unix:///tmp/supervisor.sock\n\n'
                         '[supervisord]\n'
                         'pidfile = /tmp/supervisord.pid\n'
                         'identifier = supervisor\n'
                         'directory = /tmp\n'
                         'logfile=/tmp/supervisord.log\n'
                         'loglevel=debug\n'
                         'nodaemon=false\n\n',
                         config_file=SUPERVISOR_CONF))
        self.execute('supervisord -c {config_file}'.
                     format(config_file=SUPERVISOR_CONF))

    def install_vpp(self):
        """Install VPP inside a container."""
        self.execute('ln -s /dev/null /etc/sysctl.d/80-vpp.conf')
        self.execute('apt-get update')
        if self.container.install_dkms:
            self.execute(
                'apt-get install -y dkms && '
                'dpkg -i --force-all {guest_dir}/install_dir/*.deb'.
                format(guest_dir=self.container.mnt[0].split(':')[1]))
        else:
            self.execute(
                'for i in $(ls -I \"*dkms*\" {guest_dir}/install_dir/); do '
                'dpkg -i --force-all {guest_dir}/install_dir/$i; done'.
                format(guest_dir=self.container.mnt[0].split(':')[1]))
        self.execute('apt-get -f install -y')
        self.execute('apt-get install -y ca-certificates')
        self.execute('echo "{config}" >> {config_file}'.
                     format(
                         config='[program:vpp]\n'
                         'command=/usr/bin/vpp -c /etc/vpp/startup.conf\n'
                         'autorestart=false\n'
                         'redirect_stderr=true\n'
                         'priority=1',
                         config_file=SUPERVISOR_CONF))
        self.execute('supervisorctl reload')
        self.execute('supervisorctl restart vpp')

    def restart_vpp(self):
        """Restart VPP service inside a container."""
        self.execute('supervisorctl restart vpp')
        self.execute('cat /tmp/supervisord.log')

    def create_base_vpp_startup_config(self):
        """Create base startup configuration of VPP on container.

        :returns: Base VPP startup configuration.
        :rtype: VppConfigGenerator
        """
        cpuset_cpus = self.container.cpuset_cpus

        # Create config instance
        vpp_config = VppConfigGenerator()
        vpp_config.set_node(self.container.node)
        vpp_config.add_unix_cli_listen()
        vpp_config.add_unix_nodaemon()
        vpp_config.add_unix_exec('/tmp/running.exec')
        # We will pop first core from list to be main core
        vpp_config.add_cpu_main_core(str(cpuset_cpus.pop(0)))
        # if this is not only core in list, the rest will be used as workers.
        if cpuset_cpus:
            corelist_workers = ','.join(str(cpu) for cpu in cpuset_cpus)
            vpp_config.add_cpu_corelist_workers(corelist_workers)

        return vpp_config

    def create_vpp_startup_config(self):
        """Create startup configuration of VPP without DPDK on container.
        """
        vpp_config = self.create_base_vpp_startup_config()
        vpp_config.add_plugin('disable', 'dpdk_plugin.so')

        # Apply configuration
        self.execute('mkdir -p /etc/vpp/')
        self.execute('echo "{config}" | tee /etc/vpp/startup.conf'
                     .format(config=vpp_config.get_config_str()))

    def create_vpp_startup_config_dpdk_dev(self, *devices):
        """Create startup configuration of VPP with DPDK on container.

        :param devices: List of PCI devices to add.
        :type devices: list
        """
        vpp_config = self.create_base_vpp_startup_config()
        vpp_config.add_dpdk_dev(*devices)
        vpp_config.add_dpdk_no_tx_checksum_offload()
        vpp_config.add_dpdk_log_level('debug')
        vpp_config.add_plugin('disable', 'default')
        vpp_config.add_plugin('enable', 'dpdk_plugin.so')
        vpp_config.add_plugin('enable', 'memif_plugin.so')

        # Apply configuration
        self.execute('mkdir -p /etc/vpp/')
        self.execute('echo "{config}" | tee /etc/vpp/startup.conf'
                     .format(config=vpp_config.get_config_str()))

    def create_vpp_exec_config(self, vat_template_file, **kwargs):
        """Create VPP exec configuration on container.

        :param vat_template_file: File name of a VAT template script.
        :param kwargs: Parameters for VAT script.
        :type vat_template_file: str
        :type kwargs: dict
        """
        vat_file_path = '{p}/{f}'.format(p=Constants.RESOURCES_TPL_VAT,
                                         f=vat_template_file)

        with open(vat_file_path, 'r') as template_file:
            cmd_template = template_file.readlines()
            for line_tmpl in cmd_template:
                vat_cmd = line_tmpl.format(**kwargs)
                self.execute('echo "{c}" >> /tmp/running.exec'
                             .format(c=vat_cmd.replace('\n', '')))

    def is_container_running(self):
        """Check if container is running."""
        raise NotImplementedError

    def is_container_present(self):
        """Check if container is present."""
        raise NotImplementedError

    def _configure_cgroup(self, name):
        """Configure the control group associated with a container.

        By default the cpuset cgroup is using exclusive CPU/MEM. When Docker/LXC
        container is initialized a new cgroup /docker or /lxc is created under
        cpuset parent tree. This newly created cgroup is inheriting parent
        setting for cpu/mem exclusive parameter and thus cannot be overriden
        within /docker or /lxc cgroup. This function is supposed to set cgroups
        to allow coexistence of both engines.

        :param name: Name of cgroup.
        :type name: str
        :raises RuntimeError: If applying cgroup settings via cgset failed.
        """
        ret, _, _ = self.container.ssh.exec_command_sudo(
            'cgset -r cpuset.cpu_exclusive=0 /')
        if int(ret) != 0:
            raise RuntimeError('Failed to apply cgroup settings.')

        ret, _, _ = self.container.ssh.exec_command_sudo(
            'cgset -r cpuset.mem_exclusive=0 /')
        if int(ret) != 0:
            raise RuntimeError('Failed to apply cgroup settings.')

        ret, _, _ = self.container.ssh.exec_command_sudo(
            'cgcreate -g cpuset:/{name}'.format(name=name))
        if int(ret) != 0:
            raise RuntimeError('Failed to copy cgroup settings from root.')

        ret, _, _ = self.container.ssh.exec_command_sudo(
            'cgset -r cpuset.cpu_exclusive=0 /{name}'.format(name=name))
        if int(ret) != 0:
            raise RuntimeError('Failed to apply cgroup settings.')

        ret, _, _ = self.container.ssh.exec_command_sudo(
            'cgset -r cpuset.mem_exclusive=0 /{name}'.format(name=name))
        if int(ret) != 0:
            raise RuntimeError('Failed to apply cgroup settings.')


class LXC(ContainerEngine):
    """LXC implementation."""

    def __init__(self):
        """Initialize LXC object."""
        super(LXC, self).__init__()

    def acquire(self, force=True):
        """Acquire a privileged system object where configuration is stored.

        :param force: If a container exists, destroy it and create a new
            container.
        :type force: bool
        :raises RuntimeError: If creating the container or writing the container
            config fails.
        """
        if self.is_container_present():
            if force:
                self.destroy()
            else:
                return

        image = self.container.image if self.container.image else\
            "-d ubuntu -r xenial -a amd64"

        cmd = 'lxc-create -t download --name {c.name} -- {image} '\
            '--no-validate'.format(c=self.container, image=image)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd, timeout=1800)
        if int(ret) != 0:
            raise RuntimeError('Failed to create container.')

        self._configure_cgroup('lxc')

    def create(self):
        """Create/deploy an application inside a container on system.

        :raises RuntimeError: If creating the container fails.
        """
        if self.container.mnt:
            for mount in self.container.mnt:
                host_dir, guest_dir = mount.split(':')
                entry = 'lxc.mount.entry = {host_dir} '\
                    '/var/lib/lxc/{c.name}/rootfs{guest_dir} none ' \
                    'bind,create=dir 0 0'.format(c=self.container,
                                                 host_dir=host_dir,
                                                 guest_dir=guest_dir)
                ret, _, _ = self.container.ssh.exec_command_sudo(
                    "sh -c 'echo \"{e}\" >> /var/lib/lxc/{c.name}/config'".
                    format(e=entry, c=self.container))
                if int(ret) != 0:
                    raise RuntimeError('Failed to write {c.name} config.'
                                       .format(c=self.container))

        cpuset_cpus = '{0}'.format(
            ','.join('%s' % cpu for cpu in self.container.cpuset_cpus))\
            if self.container.cpuset_cpus else ''

        ret, _, _ = self.container.ssh.exec_command_sudo(
            'lxc-start --name {c.name} --daemon'.
            format(c=self.container))
        if int(ret) != 0:
            raise RuntimeError('Failed to start container {c.name}.'.
                               format(c=self.container))
        self._lxc_wait('RUNNING')

        # Workaround for LXC to be able to allocate all cpus including isolated.
        ret, _, _ = self.container.ssh.exec_command_sudo(
            'cgset --copy-from / lxc/')
        if int(ret) != 0:
            raise RuntimeError('Failed to copy cgroup to LXC')

        ret, _, _ = self.container.ssh.exec_command_sudo(
            'lxc-cgroup --name {c.name} cpuset.cpus {cpus}'.
            format(c=self.container, cpus=cpuset_cpus))
        if int(ret) != 0:
            raise RuntimeError('Failed to set cpuset.cpus to container '
                               '{c.name}.'.format(c=self.container))

    def execute(self, command):
        """Start a process inside a running container.

        Runs the specified command inside the container specified by name. The
        container has to be running already.

        :param command: Command to run inside container.
        :type command: str
        :raises RuntimeError: If running the command failed.
        """
        env = '--keep-env {0}'.format(
            ' '.join('--set-var %s' % env for env in self.container.env))\
            if self.container.env else ''

        cmd = "lxc-attach {env} --name {c.name} -- /bin/sh -c '{command}; "\
            "exit $?'".format(env=env, c=self.container, command=command)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd, timeout=180)
        if int(ret) != 0:
            raise RuntimeError('Failed to run command inside container '
                               '{c.name}.'.format(c=self.container))

    def stop(self):
        """Stop a container.

        :raises RuntimeError: If stopping the container failed.
        """
        cmd = 'lxc-stop --name {c.name}'.format(c=self.container)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to stop container {c.name}.'
                               .format(c=self.container))
        self._lxc_wait('STOPPED|FROZEN')

    def destroy(self):
        """Destroy a container.

        :raises RuntimeError: If destroying container failed.
        """
        cmd = 'lxc-destroy --force --name {c.name}'.format(c=self.container)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to destroy container {c.name}.'
                               .format(c=self.container))

    def info(self):
        """Query and shows information about a container.

        :raises RuntimeError: If getting info about a container failed.
        """
        cmd = 'lxc-info --name {c.name}'.format(c=self.container)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to get info about container {c.name}.'
                               .format(c=self.container))

    def system_info(self):
        """Check the current kernel for LXC support.

        :raises RuntimeError: If checking LXC support failed.
        """
        cmd = 'lxc-checkconfig'

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to check LXC support.')

    def is_container_running(self):
        """Check if container is running on node.

        :returns: True if container is running.
        :rtype: bool
        :raises RuntimeError: If getting info about a container failed.
        """
        cmd = 'lxc-info --no-humanize --state --name {c.name}'\
            .format(c=self.container)

        ret, stdout, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to get info about container {c.name}.'
                               .format(c=self.container))
        return True if 'RUNNING' in stdout else False

    def is_container_present(self):
        """Check if container is existing on node.

        :returns: True if container is present.
        :rtype: bool
        :raises RuntimeError: If getting info about a container failed.
        """
        cmd = 'lxc-info --no-humanize --name {c.name}'.format(c=self.container)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        return False if int(ret) else True

    def _lxc_wait(self, state):
        """Wait for a specific container state.

        :param state: Specify the container state(s) to wait for.
        :type state: str
        :raises RuntimeError: If waiting for state of a container failed.
        """
        cmd = 'lxc-wait --name {c.name} --state "{s}"'\
            .format(c=self.container, s=state)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to wait for state "{s}" of container '
                               '{c.name}.'.format(s=state, c=self.container))


class Docker(ContainerEngine):
    """Docker implementation."""

    def __init__(self):
        """Initialize Docker object."""
        super(Docker, self).__init__()

    def acquire(self, force=True):
        """Pull an image or a repository from a registry.

        :param force: Destroy a container if exists.
        :type force: bool
        :raises RuntimeError: If pulling a container failed.
        """
        if self.is_container_present():
            if force:
                self.destroy()
            else:
                return

        cmd = 'docker pull {c.image}'.format(c=self.container)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd, timeout=1800)
        if int(ret) != 0:
            raise RuntimeError('Failed to create container {c.name}.'
                               .format(c=self.container))
        self._configure_cgroup('docker')

    def create(self):
        """Create/deploy container.

        :raises RuntimeError: If creating a container failed.
        """
        cpuset_cpus = '--cpuset-cpus={0}'.format(
            ','.join('%s' % cpu for cpu in self.container.cpuset_cpus))\
            if self.container.cpuset_cpus else ''

        cpuset_mems = '--cpuset-mems={0}'.format(self.container.cpuset_mems)\
            if self.container.cpuset_mems is not None else ''
        # Temporary workaround - disabling due to bug in memif
        cpuset_mems = ''

        env = '{0}'.format(
            ' '.join('--env %s' % env for env in self.container.env))\
            if self.container.env else ''

        command = '{0}'.format(self.container.command)\
            if self.container.command else ''

        publish = '{0}'.format(
            ' '.join('--publish %s' % var for var in self.container.publish))\
            if self.container.publish else ''

        volume = '{0}'.format(
            ' '.join('--volume %s' % mnt for mnt in self.container.mnt))\
            if self.container.mnt else ''

        cmd = 'docker run '\
            '--privileged --detach --interactive --tty --rm '\
            '--cgroup-parent docker {cpuset_cpus} {cpuset_mems} {publish} '\
            '{env} {volume} --name {container.name} {container.image} '\
            '{command}'.format(cpuset_cpus=cpuset_cpus, cpuset_mems=cpuset_mems,
                               container=self.container, command=command,
                               env=env, publish=publish, volume=volume)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to create container {c.name}'
                               .format(c=self.container))

        self.info()

    def execute(self, command):
        """Start a process inside a running container.

        Runs the specified command inside the container specified by name. The
        container has to be running already.

        :param command: Command to run inside container.
        :type command: str
        :raises RuntimeError: If runnig the command in a container failed.
        """
        cmd = "docker exec --interactive {c.name} /bin/sh -c '{command}; "\
            "exit $?'".format(c=self.container, command=command)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd, timeout=180)
        if int(ret) != 0:
            raise RuntimeError('Failed to execute command in container '
                               '{c.name}.'.format(c=self.container))

    def stop(self):
        """Stop running container.

        :raises RuntimeError: If stopping a container failed.
        """
        cmd = 'docker stop {c.name}'.format(c=self.container)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to stop container {c.name}.'
                               .format(c=self.container))

    def destroy(self):
        """Remove a container.

        :raises RuntimeError: If removing a container failed.
        """
        cmd = 'docker rm --force {c.name}'.format(c=self.container)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to destroy container {c.name}.'
                               .format(c=self.container))

    def info(self):
        """Return low-level information on Docker objects.

        :raises RuntimeError: If getting info about a container failed.
        """
        cmd = 'docker inspect {c.name}'.format(c=self.container)

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to get info about container {c.name}.'
                               .format(c=self.container))

    def system_info(self):
        """Display the docker system-wide information.

        :raises RuntimeError: If displaying system information failed.
        """
        cmd = 'docker system info'

        ret, _, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to get system info.')

    def is_container_present(self):
        """Check if container is present on node.

        :returns: True if container is present.
        :rtype: bool
        :raises RuntimeError: If getting info about a container failed.
        """
        cmd = 'docker ps --all --quiet --filter name={c.name}'\
            .format(c=self.container)

        ret, stdout, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to get info about container {c.name}.'
                               .format(c=self.container))
        return True if stdout else False

    def is_container_running(self):
        """Check if container is running on node.

        :returns: True if container is running.
        :rtype: bool
        :raises RuntimeError: If getting info about a container failed.
        """
        cmd = 'docker ps --quiet --filter name={c.name}'\
            .format(c=self.container)

        ret, stdout, _ = self.container.ssh.exec_command_sudo(cmd)
        if int(ret) != 0:
            raise RuntimeError('Failed to get info about container {c.name}.'
                               .format(c=self.container))
        return True if stdout else False


class Container(object):
    """Container class."""

    def __init__(self):
        """Initialize Container object."""
        pass

    def __getattr__(self, attr):
        """Get attribute custom implementation.

        :param attr: Attribute to get.
        :type attr: str
        :returns: Attribute value or None.
        :rtype: any
        """
        try:
            return self.__dict__[attr]
        except KeyError:
            return None

    def __setattr__(self, attr, value):
        """Set attribute custom implementation.

        :param attr: Attribute to set.
        :param value: Value to set.
        :type attr: str
        :type value: any
        """
        try:
            # Check if attribute exists
            self.__dict__[attr]
        except KeyError:
            # Creating new attribute
            if attr == 'node':
                self.__dict__['ssh'] = SSH()
                self.__dict__['ssh'].connect(value)
            self.__dict__[attr] = value
        else:
            # Updating attribute base of type
            if isinstance(self.__dict__[attr], list):
                self.__dict__[attr].append(value)
            else:
                self.__dict__[attr] = value