Node

The scherbelberg.Node class describes one node, i.e. server, within the cluster. It can represent both, a Dask worker node as well as a Dask scheduler node, see Dask CLI for more details.

The Node Class

class scherbelberg.Node(server, client, fn_private, prefix, wait, log=None)

Represents one node of the cluster, i.e. a server. Mutable.

Parameters

  • server (BoundServer) – A cloud API server object.

  • client (Client) – A cloud API client object.

  • fn_private (str) – Location of private SSH key.

  • prefix (str) – Name of cluster, used as a prefix in names of every component.

  • wait (float) – Timeout in seconds before actions are repeated or exceptions are raised.

  • log (Optional[Logger]) – Allows to pass custom logger objects. Defaults to scherbelberg’s own default logger.

__repr__()

Interactive string representation

Return type

str

async bootstrap()

Bootstraps scherbelberg’s basic infrastructure on the node, i.e.

  • System updates

  • Secure user & SSH configuration

  • TLS/SSL certificate

  • Conda-forge base install via mamba-forge

async classmethod from_async(**kwargs)

Constructs objects from this class asynchronously

Return type

NodeABC

Returns

New node object

async classmethod from_name(name, client, fn_private, prefix, wait, log=None)

Creates scherbelberg.Node object by connecting to an existing server. Raises scherbelberg.NodeNotFound if no matching server can be found.

Parameters

  • name (str) – Full name of node / server.

  • client (Client) – Cloud API client object.

  • fn_private (str) – Location of private SSH key.

  • prefix (str) – Name of cluster, used as a prefix in names of every component.

  • wait (float) – Timeout in seconds before actions are repeated or exceptions are raised.

  • log (Optional[Logger]) – Allows to pass custom logger objects. Defaults to scherbelberg’s own default logger.

Return type

NodeABC

Returns

New node object

async get_sshconfig(user=None)

Generates SSH configuration for commands that are supposed to be executed on this node.

Parameters

user (Optional[str]) – Remote user name, defaults to standard cluster user name.

Return type

SSHConfigABC

Returns

SSH configuration.

property labels: Dict[str, str]

Labels of node / server

Return type

Dict[str, str]

property name: str

Full name of node / server

Return type

str

async ping_ssh(user=None)

Checks if node can be contacted via SSH by executing an exit command on it. Performs exactly one single try. Does not raise any type of exception.

Parameters

user (Optional[str]) – Remote user name, defaults to standard cluster user name.

Return type

bool

Returns

Success (or the lack thereof).

property private_ip4: str

Private IPv4 address of node / server

Return type

str

property public_ip4: str

Public IPv4 address of node / server

Return type

str

async reboot()

Triggers a server reboot.

async start_scheduler(dask_ipc, dask_dash)

Starts Dask scheduler on node.

Parameters

  • dask_ipc (int) – Port used for Dask’s interprocess communication.

  • dask_dash (int) – Port used for Dask’s dashboard.

async start_worker(dask_ipc, dask_dash, dask_nanny, scheduler_ip4)

Starts Dask scheduler on node.

Parameters

  • dask_ipc (int) – Port used for Dask’s interprocess communication.

  • dask_dash (int) – Port used for Dask’s dashboard.

  • dask_nanny (int) – Port used for Dask’s nanny.

  • scheduler_ip4 (str) – IPv4 address of scheduler node.

property suffix: str

Suffix portion of name of node / server

Return type

str

async update()

Updates the internal cloud API server object by requesting new information about the node from the cloud API.

async wait_for_ssh(user=None)

Keeps pinging the server on SSH via scherbelberg.Node.ping_ssh() until success in wait second intervals.

Parameters

user (Optional[str]) – Remote user name, defaults to standard cluster user name.