feat: pod node selector

Author: y-young

resources/src/objects/pod.rs

@@ -7,7 +7,7 @@ use indenter::indented;
 use serde::{Deserialize, Serialize};
 use strum::{Display, EnumIter, IntoEnumIterator};
 
-use super::{function::Function, metrics, Metadata, Object};
+use super::{function::Function, metrics, Labels, Metadata, Object};
 
 #[derive(Debug, Serialize, Deserialize, Clone, PartialEq, Eq)]
 pub struct Pod {
@@ -167,6 +167,11 @@ pub struct PodSpec {
     /// Default to false.
     #[serde(default)]
     pub host_network: bool,
+    /// NodeSelector is a selector which must be true for the pod to fit on a node.
+    /// Selector which must match a node's labels
+    /// for the pod to be scheduledon that node.
+    #[serde(default)]
+    pub node_selector: Labels,
     /// NodeName is a request to schedule this pod onto a specific node.
     /// If it is non-empty, the scheduler simply schedules this pod onto that node,
     /// assuming that it fits resource requirements.

scheduler/src/algorithm/simple.rs

@@ -2,12 +2,13 @@ use resources::objects::{object_reference::ObjectReference, pod::Pod};
 
 use crate::cache::{Cache, NodeState};
 
-pub fn simple(_pod: &Pod, cache: &Cache) -> Option<ObjectReference> {
+pub fn simple(pod: &Pod, cache: &Cache) -> Option<ObjectReference> {
     let mut candidate = None;
     cache
         .node_states
         .iter()
         .filter(|(_, state)| state.is_ready)
+        .filter(|(_, state)| state.labels.matches(&pod.spec.node_selector))
         .for_each(|(_, state)| {
             if is_better_than(Some(state), candidate) {
                 candidate = Some(state);

scheduler/src/cache.rs

@@ -2,12 +2,13 @@ use std::collections::HashMap;
 
 use resources::{
     informer::Store,
-    objects::{node::Node, pod::Pod},
+    objects::{node::Node, pod::Pod, Labels},
 };
 
 #[derive(Debug, Default)]
 pub struct NodeState {
     pub name: String,
+    pub labels: Labels,
     pub is_ready: bool,
     pub pod_count: u32,
 }
@@ -78,6 +79,7 @@ impl Cache {
             node.metadata.name.to_owned(),
             NodeState {
                 name: node.metadata.name,
+                labels: node.metadata.labels,
                 is_ready,
                 ..Default::default()
             },
@@ -96,6 +98,7 @@ impl Cache {
     pub async fn calculate_node_state(&self, node: &Node) -> NodeState {
         let mut node_state = NodeState {
             name: node.metadata.name.to_owned(),
+            labels: node.metadata.labels.to_owned(),
             is_ready: node.is_ready(),
             ..Default::default()
         };