Esempio n. 1
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    def create(self, defn, check, allow_reboot, allow_recreate):
        assert isinstance(defn, HetznerDefinition)

        if self.state not in (self.RESCUE, self.UP) or check:
            self.check()

        self.set_common_state(defn)
        self.main_ipv4 = defn.main_ipv4

        if not self.robot_admin_user or not self.robot_admin_pass:
            self.log_start("creating an exclusive robot admin account for "
                           "‘{0}’...".format(self.name))
            # Create a new Admin account exclusively for this machine.
            server = self._get_server_from_main_robot(self.main_ipv4, defn)
            with self.depl._db:
                (self.robot_admin_user,
                 self.robot_admin_pass) = server.admin.create()
            self.log_end("done. ({0})".format(self.robot_admin_user))

        if not self.vm_id:
            self.log("installing machine...")
            self.reboot_rescue(install=True, partitions=defn.partitions)
            self._install_base_system()
            self._detect_hardware()
            server = self._get_server_by_ip(self.main_ipv4)
            vm_id = "nixops-{0}-{1}".format(self.depl.uuid, self.name)
            server.set_name(vm_id[:100])
            self.vm_id = vm_id
            known_hosts.remove(self.main_ipv4)
            self.just_installed = True
Esempio n. 2
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    def create(self, defn, check, allow_reboot, allow_recreate):
        assert isinstance(defn, HetznerDefinition)

        if self.state not in (self.RESCUE, self.UP) or check:
            self.check()

        self.set_common_state(defn)
        self.main_ipv4 = defn.main_ipv4

        if not self.robot_admin_user or not self.robot_admin_pass:
            self.log_start("creating an exclusive robot admin account for "
                           "‘{0}’... ".format(self.name))
            # Create a new Admin account exclusively for this machine.
            server = self._get_server_from_main_robot(self.main_ipv4, defn)
            with self.depl._db:
                (self.robot_admin_user,
                 self.robot_admin_pass) = server.admin.create()
            self.log_end("done. ({0})".format(self.robot_admin_user))

        if not self.vm_id:
            self.log("installing machine...")
            self.reboot_rescue(install=True, partitions=defn.partitions)
            self._install_base_system()
            self._detect_hardware()
            server = self._get_server_by_ip(self.main_ipv4)
            vm_id = "nixops-{0}-{1}".format(self.depl.uuid, self.name)
            server.set_name(vm_id[:100])
            self.vm_id = vm_id
            known_hosts.remove(self.main_ipv4, None)
            self.just_installed = True
Esempio n. 3
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    def create(self, defn, check, allow_reboot, allow_recreate):
        assert isinstance(defn, HetznerDefinition)

        if self.state not in (self.RESCUE, self.UP) or check:
            self.check()

        self.set_common_state(defn)
        self.main_ipv4 = defn.main_ipv4

        if not self.robot_admin_user or not self.robot_admin_pass:
            self.log_start("creating an exclusive robot admin account for "
                           "‘{0}’...".format(self.name))
            # Create a new Admin account exclusively for this machine.
            server = self._get_server_from_main_robot(self.main_ipv4, defn)
            with self.depl._db:
                (self.robot_admin_user,
                 self.robot_admin_pass) = server.admin.create()
            self.log_end("done. ({0})".format(self.robot_admin_user))

        if not self.vm_id:
            self.log("installing machine...")
            self.reboot_rescue(install=True, partitions=defn.partitions)
            self._install_base_system()
            self._detect_hardware()
            server = self._get_server_by_ip(self.main_ipv4)
            vm_id = "nixops-{0}-{1}".format(self.depl.uuid, self.name)
            # XXX: Truncated to 50 chars until the Robot allows more.
            #      And this also means, that this field is unreliable so we
            #      can't use it for uniquely identifying machine UUIDs.
            server.set_name(vm_id[:50])
            self.vm_id = vm_id
            known_hosts.remove(self.main_ipv4)
            self.just_installed = True
Esempio n. 4
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File: gce.py Progetto: NixOS/nixops
    def destroy(self, wipe=False):
        if wipe:
            self.depl.logger.warn("wipe is not supported")

        if not self.project:
            return True

        if self.state == self.MISSING:
            # The machine is down, we have nothing to do.
            return True

        try:
            node = self.node()
            question = "are you sure you want to destroy {0}?"
            if not self.depl.logger.confirm(question.format(self.full_name)):
                return False

            known_hosts.remove(self.public_ipv4, self.public_host_key)
            self.log("destroying the GCE machine...")
            node.destroy()

        except libcloud.common.google.ResourceNotFoundError:
            self.warn("seems to have been destroyed already")
        self._node_deleted()

        # Destroy volumes created for this instance.
        for k, v in self.block_device_mapping.items():
            if v.get('deleteOnTermination', False):
                self._delete_volume(v['disk_name'], v['region'], True)
            self.update_block_device_mapping(k, None)

        return True
Esempio n. 5
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    def destroy(self, wipe=False):
        if wipe:
            self.depl.logger.warn("wipe is not supported")

        if not self.project:
            return True

        try:
            node = self.node()
            question = "are you sure you want to destroy {0}?"
            if not self.depl.logger.confirm(question.format(self.full_name)):
                return False

            known_hosts.remove(self.public_ipv4, self.public_host_key)
            self.log("destroying the GCE machine...")
            node.destroy()

        except libcloud.common.google.ResourceNotFoundError:
            self.warn("seems to have been destroyed already")
        self._node_deleted()

        # Destroy volumes created for this instance.
        for k, v in self.block_device_mapping.items():
            if v.get('deleteOnTermination', False):
                self._delete_volume(v['disk_name'], v['region'], True)
            self.update_block_device_mapping(k, None)

        return True
Esempio n. 6
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    def create(self, defn, check, allow_reboot, allow_recreate):
        assert isinstance(defn, HetznerDefinition)

        if self.state not in (self.RESCUE, self.UP) or check:
            self.check()

        self.set_common_state(defn)
        self.main_ipv4 = defn.main_ipv4

        if defn.create_sub_account:
            if not self.robot_admin_user or not self.robot_admin_pass:
                self.log_start(
                    "creating an exclusive robot admin sub-account "
                    "for ‘{0}’... ".format(self.name)
                )
                server = self._get_server_from_main_robot(self.main_ipv4, defn)
                with self.depl._db:
                    (
                        self.robot_admin_user,
                        self.robot_admin_pass,
                    ) = server.admin.create()
                self.log_end("done. ({0})".format(self.robot_admin_user))
        else:
            # If available, assign user and password even if they are already
            # in the DB, so that changes to them are immediately reflected.
            # If not available, we use the ones from the DB.
            (robot_user, robot_pass) = self._get_robot_user_and_pass(
                defn=defn,
                default_user=self.robot_admin_user,
                default_pass=self.robot_admin_pass,
            )
            if (
                robot_user != self.robot_admin_user
                or robot_pass != self.robot_admin_pass
            ):
                with self.depl._db:
                    (self.robot_admin_user, self.robot_admin_pass) = (
                        robot_user,
                        robot_pass,
                    )

        if not self.vm_id:
            self.log("installing machine...")
            self.reboot_rescue(install=True, partitions=defn.partitions)
            self._install_base_system()
            self._detect_hardware()
            server = self._get_server_by_ip(self.main_ipv4)
            vm_id = "nixops-{0}-{1}".format(self.depl.uuid, self.name)
            server.set_name(vm_id[:100])
            self.vm_id = vm_id
            known_hosts.remove(self.main_ipv4, None)
            self.just_installed = True
            self.state_version = defn.config.nixosRelease
Esempio n. 7
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 def _reset(self) -> None:
     assert self.depl
     if all((self.public_ipv4, self._public_host_key)):
         known_hosts.remove(self.public_ipv4, self._public_host_key)
     with self.depl._db:
         self.state = self.MISSING
         self.vm_id = None
         self.image_id = None
         self.location = None
         self.public_ipv4 = None
         self.server_type = None
         self.hw_info = None
         self._ssh_public_key = None
         self._ssh_private_key = None
         self._public_host_key = None
Esempio n. 8
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    def create(self, defn, check, allow_reboot, allow_recreate):
        assert isinstance(defn, HetznerDefinition)

        if self.state not in (self.RESCUE, self.UP) or check:
            self.check()

        self.set_common_state(defn)
        self.main_ipv4 = defn.main_ipv4

        if defn.create_sub_account:
            if not self.robot_admin_user or not self.robot_admin_pass:
                self.log_start("creating an exclusive robot admin sub-account "
                               "for ‘{0}’... ".format(self.name))
                server = self._get_server_from_main_robot(self.main_ipv4, defn)
                with self.depl._db:
                    (self.robot_admin_user,
                     self.robot_admin_pass) = server.admin.create()
                self.log_end("done. ({0})".format(self.robot_admin_user))
        else:
            # If available, assign user and password even if they are already
            # in the DB, so that changes to them are immediately reflected.
            # If not available, we use the ones from the DB.
            (robot_user, robot_pass) = self._get_robot_user_and_pass(
                defn=defn,
                default_user=self.robot_admin_user,
                default_pass=self.robot_admin_pass,
            )
            if robot_user != self.robot_admin_user or \
               robot_pass != self.robot_admin_pass:
                with self.depl._db:
                    (self.robot_admin_user,
                     self.robot_admin_pass) = (robot_user, robot_pass)

        if not self.vm_id:
            self.log("installing machine...")
            self.reboot_rescue(install=True, partitions=defn.partitions)
            self._install_base_system()
            self._detect_hardware()
            server = self._get_server_by_ip(self.main_ipv4)
            vm_id = "nixops-{0}-{1}".format(self.depl.uuid, self.name)
            server.set_name(vm_id[:100])
            self.vm_id = vm_id
            known_hosts.remove(self.main_ipv4, None)
            self.just_installed = True
            self.state_version = defn.config['nixosRelease']
Esempio n. 9
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class HetznerCloudState(MachineState[HetznerCloudDefinition]):
    """
    State of a Hetzner Cloud machine.
    """
    @classmethod
    def get_type(cls):
        return "hetznercloud"

    state = attr_property("state", MachineState.MISSING, int)  # override
    vm_id = attr_property("vmId", None, int)  # override type
    api_token = attr_property("hetznerCloud.apiToken", None)
    public_ipv4 = attr_property("publicIpv4", None)
    public_ipv6 = attr_property("publicIpv6", None)
    private_ipv4 = attr_property("privateIpv4", None)
    public_client_key = attr_property("hetznerCloud.publicClientKey", None)
    private_client_key = attr_property("hetznerCloud.privateClientKey", None)
    public_host_key = attr_property("hetznerCloud.publicHostKey", None)
    private_host_key = attr_property("hetznerCloud.privateHostKey", None)
    legacy_if_scheme = attr_property("legacyIfScheme", None, bool)
    labels = attr_property("hetznerCloud.labels", {}, "json")
    location = attr_property("hetznerCloud.location", None)
    server_name = attr_property("hetznerCloud.serverName", None)
    server_type = attr_property("hetznerCloud.serverType", None)
    server_networks = attr_property("hetznerCloud.serverNetworks", {}, "json")
    volumes = attr_property("hetznerCloud.volumes", {}, "json")
    ip_addresses = attr_property("hetznerCloud.ipAddresses", {}, "json")

    def __init__(self, depl: Deployment, name: str, id):
        MachineState.__init__(self, depl, name, id)
        self._client = None

    def cleanup_state(self) -> None:
        """ Discard all state pertaining to an instance. """
        with self.depl._db:
            self.vm_id = None
            self.public_ipv4 = None
            self.public_ipv6 = None
            self.private_client_key = None
            self.public_client_key = None
            self.private_host_key = None
            self.public_host_key = None
            self.legacy_if_scheme = None
            self.location = None
            self.server_name = None
            self.server_type = None
            self.server_networks = {}
            self.labels = {}
            self.volumes = {}
            self.ip_addresses = {}

    def show_type(self):
        s = f"{super(HetznerCloudState, self).show_type()}"
        if self.location:
            s += f" [{self.location}; {self.server_type}]"
        return s

    @property
    def full_name(self) -> str:
        return f"Hetzner Cloud Server ‘{self.name}’"

    def get_instance(self) -> BoundServer:
        try:
            return self.get_client().servers.get_by_id(self.vm_id)
        except APIException as e:
            if e.code == "not_found":
                self.logger.warn(
                    f"{self.full_name} was deleted from outside of nixops")
                return None
            else:
                raise

    def get_client(self) -> Client:
        """
        Generic method to get or create a Hetzner Cloud client.
        """
        if self._client:
            return self._client

        new_api_token = self.api_token or os.environ.get("HCLOUD_API_TOKEN")
        if new_api_token is not None:
            self.api_token = new_api_token

        if self.api_token is None:
            raise Exception("please set ‘apiToken’ or $HCLOUD_API_TOKEN")

        self._client = Client(token=self.api_token)
        return self._client

    def get_common_labels(self) -> Dict[str, str]:
        labels = {
            "CharonNetworkUUID": self.depl.uuid,
            "CharonInstanceName": self.name,
            "CharonStateFileHost": socket.gethostname(),
            "CharonStateFileUser": getpass.getuser(),
        }
        pattern = "^$|(?i)((?=^[a-z0-9])[a-z0-9._-]{0,63}[a-z0-9]$)"
        file_name = os.path.basename(self.depl._db.db_file)
        if re.match(pattern, file_name):
            labels["CharonStateFileName"] = file_name
        if self.depl.name:
            labels["CharonNetworkName"] = self.depl.name
        return labels

    def get_ssh_name(self) -> str:
        if not self.public_ipv4:
            raise Exception(
                f"{self.full_name} does not have a public IP address (yet)")
        return self.public_ipv4

    def get_ssh_private_key_file(self) -> str:
        return self._ssh_private_key_file or self.write_ssh_private_key(
            self.private_client_key)

    def get_ssh_flags(self, *args, **kwargs) -> List[str]:
        super_flags = super(HetznerCloudState,
                            self).get_ssh_flags(*args, **kwargs)
        return super_flags + ["-i", self.get_ssh_private_key_file()]

    def get_udev_name(self, volume_id: str) -> str:
        return f"/dev/disk/by-id/scsi-0HC_Volume_{volume_id}"

    def get_physical_spec(self) -> Dict[Any, Any]:

        ipv4 = [{"address": self.public_ipv4, "prefixLength": 32}]
        ipv6 = [{"address": self.public_ipv6[:-3], "prefixLength": 64}]
        for addr in self.ip_addresses.values():
            try:
                socket.inet_pton(socket.AF_INET, addr)
                ipv4.append({"address": addr, "prefixLength": 32})
            except socket.error:  # not a valid address ipv4
                ipv6.append({"address": addr, "prefixLength": 64})

        def get_interface_name(i: int) -> str:
            return f"ens{10+i}" if self.legacy_if_scheme else f"enp{7+i}s0"

        spec = {
            "imports":
            [RawValue("<nixpkgs/nixos/modules/profiles/qemu-guest.nix>")],
            ("boot", "loader", "grub", "device"):
            "nodev",
            ("fileSystems", "/"): {
                "device": "/dev/sda1",
                "fsType": "ext4"
            },
            **{("fileSystems", v["mountPoint"]): {
                   "fsType": v["fsType"],
                   "device": v["device"],
               }
               for k, v in self.volumes.items() if v["mountPoint"]},
            # Hetzner Cloud networking defaults
            ("networking", "defaultGateway"):
            "172.31.1.1",
            ("networking", "nameservers"): [
                "213.133.98.98",
                "213.133.99.99",
                "213.133.100.100",
            ],
            (
                "networking",
                "interfaces",
                "ens3" if self.legacy_if_scheme else "enp1s0",
            ): {
                ("ipv4", "addresses"): ipv4,
                ("ipv6", "addresses"): ipv6,
                "useDHCP": True,
            },
            ("users", "extraUsers", "root", "openssh", "authorizedKeys", "keys"):
            [self.public_client_key],
        }

        for i, v in enumerate(self.server_networks.values()):
            private_ipv4_addresses = [{
                "address": addr,
                "prefixLength": 32
            } for addr in [v["privateIpAddress"]] + v["aliasIpAddresses"]]
            spec[("networking", "interfaces", get_interface_name(i))] = {
                ("ipv4", "addresses"): private_ipv4_addresses,
                "useDHCP": True,
            }

        for v in self.volumes.values():
            if v["fsType"] == "xfs":
                spec[("boot", "kernelModules")] = ["xfs"]
                break

        return spec

    def _update_attr(self, attr: str, k: str, v: Optional[Dict[str,
                                                               Any]]) -> None:
        x = getattr(self, attr)
        if v is None:
            x.pop(k, None)
        else:
            x[k] = v
        setattr(self, attr, x)

    def _handle_changed_server_networks(self, defn: HetznerCloudDefinition,
                                        allow_recreate: bool) -> None:
        """
        Detects and corrects any virtual network state desynchronisation.
        """

        attached: Set[str] = {
            x.network.id
            for x in self.get_instance().private_net
        }

        # Detach server from networks
        for name in self.server_networks.keys():
            nw: Optional[BoundNetwork] = self.get_client(
            ).networks.get_by_name(name)

            # Detect destroyed networks
            if nw is None:
                if name not in defn.server_networks:  # we dont need it
                    self.logger.warn(
                        f"forgetting about network ‘{name}’ that no longer exists"
                        " and is no longer needed by the deployment specification"
                    )
                    self._update_attr("server_networks", name, None)
                else:  # we do need it
                    raise Exception(
                        f"network ‘{name}’ (used by {self.full_name}) no longer exists;"
                        " run ‘nixops deploy --check’ to update resource state"
                    )
            # Detect network detachment
            elif nw.id not in attached:
                self.logger.warn(
                    f"instance was manually detached from network ‘{name}’ [{nw.id}]"
                )
                if name in defn.server_networks:
                    self._update_attr("server_networks", name, None)
            # Detach from existing networks if required.
            elif name not in defn.server_networks:
                self.logger.log(f"detaching from network ‘{name}’ [{nw.id}]")
                self.get_client().servers.detach_from_network(
                    server=Server(self.vm_id),
                    network=nw).wait_until_finished()
                self._update_attr("server_networks", name, None)

        # Attach server to networks
        for name, x in defn.server_networks.items():
            if name not in self.server_networks:
                nw = self.get_client().networks.get_by_name(name)

                if nw is None:
                    raise Exception(
                        f"tried to attach instance to network ‘{name}’"
                        " but it doesn't exist...")

                # NixOps will update machines in parallel, so retry
                # network attachment to deal with resource conflict.
                def attach_to_network() -> bool:
                    try:
                        self.wait_on_action(
                            self.get_client().servers.attach_to_network(
                                server=Server(self.vm_id),
                                network=nw,
                                ip=x["privateIpAddress"],
                                alias_ips=x["aliasIpAddresses"],
                            ))
                    except APIException as e:
                        if e.code == "conflict":
                            return False
                        else:
                            raise
                    else:
                        self._update_attr("server_networks", x["network"], x)
                        return True

                self.logger.log(
                    f"attaching instance to network ‘{name}’ [{nw.id}]...")
                check_wait(attach_to_network)

    def _handle_changed_floating_ips(self, defn: HetznerCloudDefinition,
                                     allow_recreate: bool) -> None:
        """
        Detects and corrects any floating IP state desynchronisation.
        """

        assigned: Set[str] = {
            x.name
            for x in self.get_instance().public_net.floating_ips
        }

        for name in self.ip_addresses.keys():
            fip: Optional[BoundFloatingIP] = self.get_client(
            ).floating_ips.get_by_name(name)

            # Detect manually destroyed floating IPs
            if fip is None:
                if name not in defn.ip_addresses:  # we dont need it
                    self.logger.warn(
                        f"forgetting about floating IP ‘{name}’ that no longer"
                        " exists and is no longer needed by the deployment"
                        " specification")
                    self._update_attr("ip_addresses", name, None)
                else:
                    if name.startswith("nixops-" + self.depl.uuid):
                        raise Exception(
                            f"floating IP ‘{name}’ (used by {self.full_name})"
                            " no longer exists; run ‘nixops deploy --check’"
                            " to update resource state")
                    else:
                        raise Exception(
                            f"floating IP ‘{name}’ (used by {self.full_name})"
                            " was manually destroyed")

            # Detect unassigned floating IPs
            elif name not in assigned:
                if name not in defn.ip_addresses:  # we dont need it
                    self.logger.warn(
                        f"forgetting about unassigned floating IP ‘{name}’ [{fip.id}]"
                        " that is no longer needed by the deployment specification"
                    )
                else:  # we do need it
                    self.logger.warn(
                        f"floating IP ‘{name}’ [{fip.id}] was manually unassigned;"
                        " will reassign it.")
                    self._update_attr("ip_addresses", name, None)

        # Assign missing floating IPs.
        for name in defn.ip_addresses:
            if name not in self.ip_addresses:
                fip = self.get_client().floating_ips.get_by_name(name)
                if fip is None:
                    raise Exception(f"tried to assign floating IP ‘{name}’"
                                    " but it doesn't exist...")
                self.logger.log(
                    f"assigning floating IP ‘{name}’ [{fip.id}]...")
                self.wait_on_action(fip.assign(Server(self.vm_id)))
                self._update_attr("ip_addresses", name, fip.ip)

    def _handle_changed_volumes(self, defn: HetznerCloudDefinition,
                                allow_recreate: bool) -> None:
        """
        Detects and corrects any volume state desynchronisation.
        """

        attached: Set[str] = {x.name for x in self.get_instance().volumes}

        for name in self.volumes.keys():
            volume: Optional[BoundVolume] = self.get_client(
            ).volumes.get_by_name(name)

            # Detect destroyed volumes.
            if volume is None:
                if name not in defn.volumes:  # we dont need it
                    self.logger.warn(
                        f"forgetting about volume ‘{name}’ that no longer exists"
                        " and is no longer needed by the deployment specification"
                    )
                else:
                    if name.startswith("nixops-" + self.depl.uuid):
                        raise Exception(
                            f"volume ‘{name}’ (used by {self.full_name}) no longer exists;"
                            " run ‘nixops deploy --check’ to update resource state"
                        )
                    else:
                        raise Exception(
                            f"volume ‘{name}’ (used by {self.full_name}) was"
                            " manually destroyed")
            # Detect detached volumes.
            elif name not in attached:
                if name not in defn.volumes:  # we dont need it
                    self.logger.warn(
                        f"forgetting about detached volume ‘{name}’ [{volume.id}]"
                        " that is no longer needed by the deployment specification"
                    )
                else:  # we do need it
                    self.logger.warn(
                        f"volume ‘{name}’ [{volume.id}] was manually detached;"
                        " will reattach it")
                self._update_attr("volumes", name, None)
            # Detach existing attached volumes if required.
            elif name not in defn.volumes:
                self.logger.warn(
                    f"detaching volume ‘{name}’ [{volume.id}] that is no longer"
                    " needed by the deployment specification")
                volume.detach().wait_until_finished()
                self._update_attr("volumes", name, None)

        # Attach missing volumes. resize filesystems if required, before mounting.
        for name, v in defn.volumes.items():
            if name not in self.volumes:

                # Check if it exists. resources will have been created if user ran check,
                # but prexisting vols which got deleted may be gone (detected in code above)
                volume = self.get_client().volumes.get_by_name(name)

                if volume is None:
                    self.logger.warn(
                        f"tried to attach non-NixOps managed volume ‘{name}’,"
                        " but it doesn't exist... skipping")
                    continue
                elif volume.location.name != self.location:
                    raise Exception(
                        f"volume ‘{name}’ [{volume.id}] is in a different location"
                        " to {self.full_name}; attempting to attach it will fail."
                    )
                elif (volume.server and volume.server.id != self.vm_id
                      and self.depl.logger.confirm(
                          f"volume ‘{name}’ is in use by instance ‘{volume.server.id}’,"
                          " are you sure you want to attach this volume?")
                      ):  # noqa: E124
                    self.logger.log(
                        f"detaching volume ‘{name}’ from instance ‘{volume.server.id}’..."
                    )
                    volume.detach().wait_until_finished()
                    volume.server = None

                # Attach volume.

                self.logger.log(f"attaching volume ‘{name}’ [{volume.id}]... ")
                volume.attach(Server(self.vm_id)).wait_until_finished()

                # Wait until the device is visible in the instance.

                v["device"] = self.get_udev_name(volume.id)

                def check_device() -> bool:
                    return 0 == self.run_command(f"test -e {v['device']}",
                                                 check=False)

                if not check_wait(
                        check_device, initial=1, max_tries=10,
                        exception=False):
                    # If stopping times out, then do an unclean shutdown.
                    self.logger.log_end("(timed out)")
                    self.logger.log(f"can't find device ‘{v['device']}’...")
                    self.logger.log("available devices:")
                    self.run_command("lsblk")
                    raise Exception("operation timed out")
                else:
                    self._update_attr("volumes", name, v)
                    self.logger.log_end("")

            # Grow filesystems on resource based volumes.

            # We want to grow the fs when its volume gets resized, but if the
            # volume isn't attached to any server at the time, thats not possible.
            # Blindly trying to grow all volumes when mounting them just in case
            # they got resized while they were orphaned is bad. Workaround:
            # the needsFSResize attribute of VolumeState is set when the volume
            # gets resized by NixOps. When attaching a volume NixOps will use this
            # flag to decide whether to grow the filesystem.

            if name.startswith("nixops-" + self.depl.uuid):
                res = self.depl.get_typed_resource(name[44:],
                                                   "hetznercloud-volume",
                                                   VolumeState)
                # get correct option definitions for volume resources
                v["size"] = res._state["size"]
                v["fsType"] = res._state["fsType"]
                v["device"] = self.get_udev_name(res._state["resourceId"])

                question = (
                    f"volume {name} was resized, do you wish to grow its"
                    " filesystem to fill the space?")
                op = (f"umount {v['device']} ;"
                      f"e2fsck -fy {v['device']} &&"
                      f"resize2fs {v['device']}")

                if (v["fsType"] == "ext4" and res.needsFSResize
                        and self.depl.logger.confirm(question)
                        and self.run_command(op, check=False) == 0):
                    with res.depl._db:
                        res.needsFSResize = False

                self._update_attr("volumes", name, v)

            if v["mountPoint"]:
                volume = self.get_client().volumes.get_by_name(name)
                v["device"] = self.get_udev_name(volume.id)
                self._update_attr("volumes", name, v)

    def after_activation(self, defn: HetznerCloudDefinition) -> None:

        # Unlike ext4, xfs filesystems must be resized while the underlying drive is mounted.
        # Thus this operation is delayed until after activation.
        for name, v in self.volumes.items():
            if (name.startswith("nixops-" + self.depl.uuid) and v["mountPoint"]
                    and v["fsType"] == "xfs"):
                res = self.depl.get_typed_resource(name[44:],
                                                   "hetznercloud-volume",
                                                   VolumeState)
                question = (
                    f"volume {name} was resized, do you wish to grow its"
                    " filesystem to fill the space?")
                if (res.needsFSResize and self.depl.logger.confirm(question)
                        and 0 == self.run_command(
                            f"xfs_growfs {v['mountPoint']}", check=False)):
                    with res.depl._db:
                        res.needsFSResize = False

    def create_after(
            self, resources,
            defn: HetznerCloudDefinition) -> Set[HetznerCloudResourceState]:
        return {
            r
            for r in resources if isinstance(r, FloatingIPState)
            or isinstance(r, NetworkState) or isinstance(r, VolumeState)
        }

    def _create_ssh_key(self, public_key: str) -> BoundSSHKey:
        """Create or get a hetzner cloud ssh key."""
        public_key = public_key.strip()
        hetzner_ssh_keys: List[BoundSSHKey] = self.get_client(
        ).ssh_keys.get_all()
        name: str = f"nixops-{self.depl.uuid}-{self.name}"
        for key in hetzner_ssh_keys:
            if key.public_key.strip() == public_key:
                return key
            elif key.name == name:
                self.get_client().ssh_keys.delete(key)
        ssh_key: BoundSSHKey = self.get_client().ssh_keys.create(
            name=name,
            public_key=public_key,
        )
        return ssh_key

    def _create_instance(self, defn) -> None:
        if not self.public_client_key:
            (private, public) = create_key_pair(type="ed25519")
            self.public_client_key = public
            self.private_client_key = private

        if not self.public_host_key:
            (private, public) = create_key_pair(type="ed25519")
            self.public_host_key = public
            self.private_host_key = private

        location: BoundLocation = self.get_client().locations.get_by_name(
            defn.location)

        ssh_keys: List[BoundSSHKey] = [
            self._create_ssh_key(self.public_client_key)
        ]

        # Ensure host keys get injected into the base OS
        user_data = ("#cloud-config\n"
                     "ssh_keys:\n"
                     "  ed25519_public: {0}\n"
                     "  ed25519_private: |\n"
                     "    {1}").format(
                         self.public_host_key,
                         self.private_host_key.replace("\n", "\n    "))

        self.logger.log_start(
            f"creating {defn.server_type} server at {location.description}...")
        response = self.get_client().servers.create(
            name=defn.server_name,
            labels={
                **self.get_common_labels(),
                **dict(defn.labels)
            },
            location=location,
            server_type=ServerType(defn.server_type),
            ssh_keys=ssh_keys,
            user_data=user_data,
            image=Image(name="ubuntu-20.04"),  # for lustration
            start_after_create=True,
        )

        self.state = self.STARTING
        self.wait_on_action(response.action)

        with self.depl._db:
            self.vm_id = response.server.id
            self.public_ipv4 = response.server.public_net.ipv4.ip
            self.public_ipv6 = response.server.public_net.ipv6.ip
            self.server_name = defn.server_name
            self.server_type = defn.server_type
            self.legacy_if_scheme = defn.server_type.startswith("cx")
            self.location = defn.location
            self.labels = dict(defn.labels)
            self.private_host_key = None

        known_hosts.add(self.public_ipv4, self.public_host_key)
        self.logger.log_end(f"{self.public_ipv4}")

    def create(  # noqa: C901
        self,
        defn: HetznerCloudDefinition,
        check: bool,
        allow_reboot: bool,
        allow_recreate: bool,
    ) -> None:
        self.api_token = defn.api_token

        if self.state != self.UP:
            check = True

        self.set_common_state(defn)

        if self.api_token and self.api_token != defn.api_token:
            raise Exception("cannot change api token of an existing instance")

        # Destroy the instance (if allowed) to handle attribute changes which
        # require recreating i.e. location
        if (self.vm_id and allow_recreate and self.location != defn.location
                and self.depl.logger.confirm(
                    "changing server location requires recreate, are you sure?"
                )):
            self._destroy()

        # Stop the instance (if allowed) to handle attribute changes which
        # require rebooting i.e. server_type
        if self.vm_id and allow_reboot and self.server_type != defn.server_type:
            self.stop()
            check = True

        # Check whether the instance hasn't been killed behind our backs.
        # Handle changed server type.
        # Restart stopped instances.
        if self.vm_id and check:
            instance = self.get_instance()

            if instance is None or instance.status in {"deleting"}:
                if not allow_recreate:
                    raise Exception(
                        f"{self.full_name} went away;"
                        " use ‘--allow-recreate’ to create a new one")
                status = instance.status if instance else "gone"
                self.logger.log(
                    f"{self.full_name} went away (state ‘{status}’), will recreate"
                )
                self.cleanup_state()

            # Modify the server type, if desired. TODO store disk size
            # in state to enable option to later downsize server type.
            if instance.status == "off" and self.server_type != defn.server_type:
                self.logger.log_start(
                    f"changing server type from ‘{self.server_type}’ to"
                    f" ‘{defn.server_type}’; may take a few minutes...")
                instance.change_type(ServerType(defn.server_type),
                                     upgrade_disk=True).wait_until_finished()
                self.logger.log_end("done!")

                with self.depl._db:
                    self.server_type = defn.server_type

                self.logger.log("instance was stopped, restarting...")
                self.start()

        # Provision the instance.
        if not self.vm_id:
            self._create_instance(defn)
            self.wait_for_ssh()
            self.state = self.RESCUE
            self.logger.log_start("running nixos-infect")
            self.run_command("bash </dev/stdin 2>&1", stdin=open(INFECT_PATH))
            self.logger.log("rebooting into NixOS 😎")
            self.reboot_sync()
            self.state = self.UP

        if self.location != defn.location:
            raise Exception("cannot change location of an existing instance"
                            f" (from ‘{self.location}‘ to ‘{defn.location}‘);"
                            " use ‘--allow-recreate’")

        if self.server_type != defn.server_type:
            raise Exception(
                "cannot change server type of a running instance"
                f" (from ‘{self.server_type}‘ to ‘{defn.server_type}‘);"
                " use ‘--allow-reboot’")

        # Update name or labels if they have changed.
        if self.server_name != defn.server_name or self.labels != defn.labels:
            self.logger.log("updating trivial modified attributes")
            self.get_instance().update(defn.server_name, {
                **self.get_common_labels(),
                **dict(defn.labels)
            })

        self._handle_changed_floating_ips(defn, allow_recreate)
        self._handle_changed_volumes(defn, allow_recreate)
        self._handle_changed_server_networks(defn, allow_recreate)

    def _destroy(self) -> None:
        if self.state != self.UP:
            return
        self.logger.log(f"destroying {self.full_name}")

        # Detach volumes
        for name, v in self.volumes.items():
            self.logger.log(f"detaching volume {name}...")
            self.get_client().volumes.get_by_name(
                name).detach().wait_until_finished()

        if (instance := self.get_instance()) is not None:
            instance.delete()

        # Remove host ssh key.

        self.get_client().ssh_keys.get_by_name(
            f"nixops-{self.depl.uuid}-{self.name}").delete()
        known_hosts.remove(self.public_ipv4, self.public_host_key)

        self.cleanup_state()