Struct k8s_csi::v1_3_0::TopologyRequirement

pub struct TopologyRequirement {
    pub requisite: Vec<Topology>,
    pub preferred: Vec<Topology>,
}

Fields

requisite: Vec<Topology>

Specifies the list of topologies the provisioned volume MUST be accessible from. This field is OPTIONAL. If TopologyRequirement is specified either requisite or preferred or both MUST be specified.

If requisite is specified, the provisioned volume MUST be accessible from at least one of the requisite topologies.

Given x = number of topologies provisioned volume is accessible from n = number of requisite topologies The CO MUST ensure n >= 1. The SP MUST ensure x >= 1 If x==n, then the SP MUST make the provisioned volume available to all topologies from the list of requisite topologies. If it is unable to do so, the SP MUST fail the CreateVolume call. For example, if a volume should be accessible from a single zone, and requisite = {"region": "R1", "zone": "Z2"} then the provisioned volume MUST be accessible from the "region" "R1" and the "zone" "Z2". Similarly, if a volume should be accessible from two zones, and requisite = {"region": "R1", "zone": "Z2"}, {"region": "R1", "zone": "Z3"} then the provisioned volume MUST be accessible from the "region" "R1" and both "zone" "Z2" and "zone" "Z3".

If x<n, then the SP SHALL choose x unique topologies from the list of requisite topologies. If it is unable to do so, the SP MUST fail the CreateVolume call. For example, if a volume should be accessible from a single zone, and requisite = {"region": "R1", "zone": "Z2"}, {"region": "R1", "zone": "Z3"} then the SP may choose to make the provisioned volume available in either the "zone" "Z2" or the "zone" "Z3" in the "region" "R1". Similarly, if a volume should be accessible from two zones, and requisite = {"region": "R1", "zone": "Z2"}, {"region": "R1", "zone": "Z3"}, {"region": "R1", "zone": "Z4"} then the provisioned volume MUST be accessible from any combination of two unique topologies: e.g. "R1/Z2" and "R1/Z3", or "R1/Z2" and "R1/Z4", or "R1/Z3" and "R1/Z4".

If x>n, then the SP MUST make the provisioned volume available from all topologies from the list of requisite topologies and MAY choose the remaining x-n unique topologies from the list of all possible topologies. If it is unable to do so, the SP MUST fail the CreateVolume call. For example, if a volume should be accessible from two zones, and requisite = {"region": "R1", "zone": "Z2"} then the provisioned volume MUST be accessible from the "region" "R1" and the "zone" "Z2" and the SP may select the second zone independently, e.g. "R1/Z4".

preferred: Vec<Topology>

Specifies the list of topologies the CO would prefer the volume to be provisioned in.

This field is OPTIONAL. If TopologyRequirement is specified either requisite or preferred or both MUST be specified.

An SP MUST attempt to make the provisioned volume available using the preferred topologies in order from first to last.

If requisite is specified, all topologies in preferred list MUST also be present in the list of requisite topologies.

If the SP is unable to to make the provisioned volume available from any of the preferred topologies, the SP MAY choose a topology from the list of requisite topologies. If the list of requisite topologies is not specified, then the SP MAY choose from the list of all possible topologies. If the list of requisite topologies is specified and the SP is unable to to make the provisioned volume available from any of the requisite topologies it MUST fail the CreateVolume call.

Example 1: Given a volume should be accessible from a single zone, and requisite = {"region": "R1", "zone": "Z2"}, {"region": "R1", "zone": "Z3"} preferred = {"region": "R1", "zone": "Z3"} then the the SP SHOULD first attempt to make the provisioned volume available from "zone" "Z3" in the "region" "R1" and fall back to "zone" "Z2" in the "region" "R1" if that is not possible.

Example 2: Given a volume should be accessible from a single zone, and requisite = {"region": "R1", "zone": "Z2"}, {"region": "R1", "zone": "Z3"}, {"region": "R1", "zone": "Z4"}, {"region": "R1", "zone": "Z5"} preferred = {"region": "R1", "zone": "Z4"}, {"region": "R1", "zone": "Z2"} then the the SP SHOULD first attempt to make the provisioned volume accessible from "zone" "Z4" in the "region" "R1" and fall back to "zone" "Z2" in the "region" "R1" if that is not possible. If that is not possible, the SP may choose between either the "zone" "Z3" or "Z5" in the "region" "R1".

Example 3: Given a volume should be accessible from TWO zones (because an opaque parameter in CreateVolumeRequest, for example, specifies the volume is accessible from two zones, aka synchronously replicated), and requisite = {"region": "R1", "zone": "Z2"}, {"region": "R1", "zone": "Z3"}, {"region": "R1", "zone": "Z4"}, {"region": "R1", "zone": "Z5"} preferred = {"region": "R1", "zone": "Z5"}, {"region": "R1", "zone": "Z3"} then the the SP SHOULD first attempt to make the provisioned volume accessible from the combination of the two "zones" "Z5" and "Z3" in the "region" "R1". If that's not possible, it should fall back to a combination of "Z5" and other possibilities from the list of requisite. If that's not possible, it should fall back to a combination of "Z3" and other possibilities from the list of requisite. If that's not possible, it should fall back to a combination of other possibilities from the list of requisite.

Trait Implementations

impl Clone for TopologyRequirement

fn clone(&self) -> TopologyRequirement

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TopologyRequirement

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for TopologyRequirement

fn default() -> TopologyRequirement

Returns the "default value" for a type.

impl Message for TopologyRequirement

fn encode_raw<B>(&self, buf: &mut B) where
    B: BufMut, 

fn merge_field<B>(
    &mut self,
    tag: u32,
    wire_type: WireType,
    buf: &mut B,
    ctx: DecodeContext
) -> Result<(), DecodeError> where
    B: Buf, 

fn encoded_len(&self) -> usize

Returns the encoded length of the message without a length delimiter.

fn clear(&mut self)

Clears the message, resetting all fields to their default.

fn encode<B>(&self, buf: &mut B) -> Result<(), EncodeError> where
    B: BufMut, 

Encodes the message to a buffer.

fn encode_length_delimited<B>(&self, buf: &mut B) -> Result<(), EncodeError> where
    B: BufMut, 

Encodes the message with a length-delimiter to a buffer.

fn decode<B>(buf: B) -> Result<Self, DecodeError> where
    B: Buf,
    Self: Default, 

Decodes an instance of the message from a buffer.

fn decode_length_delimited<B>(buf: B) -> Result<Self, DecodeError> where
    B: Buf,
    Self: Default, 

Decodes a length-delimited instance of the message from the buffer.

fn merge<B>(&mut self, buf: B) -> Result<(), DecodeError> where
    B: Buf, 

Decodes an instance of the message from a buffer, and merges it into self.

fn merge_length_delimited<B>(&mut self, buf: B) -> Result<(), DecodeError> where
    B: Buf, 

Decodes a length-delimited instance of the message from buffer, and merges it into self.

impl PartialEq<TopologyRequirement> for TopologyRequirement

fn eq(&self, other: &TopologyRequirement) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &TopologyRequirement) -> bool

This method tests for !=.

impl StructuralPartialEq for TopologyRequirement