Use address type (IP vs DNS) configured by ListenerClass (#233)

* Make preferred NodePort address type configurable

* Respect preferred address type for LoadBalancer and ClusterIP services too

* Changelog

* Docs

* Test both DNS and IP address types

* Add node_primary_address tests, simplified from @sbernauer's

* Split node_primary_addresses into a separate module

* Split the rest of utils

* Reword changelog a bit

* The op-rs PR was merged

Author: nightkr

CHANGELOG.md

@@ -4,9 +4,14 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+### Added
+
+- `Listener.status.addresses` can now be configured to prefer either IP addresses or DNS hostnames ([#233]).
+
 ### Changed
 
-- Listener.status.addresses for NodePort listeners now includes replicas that are currently unavailable ([#231]).
+- `Listener.status.addresses` for NodePort listeners now includes replicas that are currently unavailable ([#231]).
+- `Listener.status.addresses` now defaults to DNS hostnames for all service types (previously NodePort and ClusterIP would prefer IP addresses, [#233]).
 
 ### Fixed
 
@@ -15,6 +20,7 @@ All notable changes to this project will be documented in this file.
 - Propagate `ListenerClass.spec.serviceAnnotations` to the created Services ([#234]).
 
 [#231]: https://github.com/stackabletech/listener-operator/pull/231
+[#233]: https://github.com/stackabletech/listener-operator/pull/233
 [#234]: https://github.com/stackabletech/listener-operator/pull/234
 
 ## [24.7.0] - 2024-07-24

Cargo.lock

@@ -21,7 +21,7 @@ prost = "0.13"
 prost-types = "0.13"
 serde = "1.0"
 snafu = "0.8"
-stackable-operator = { git = "https://github.com/stackabletech/operator-rs.git", tag = "stackable-operator-0.76.0" }
+stackable-operator = { git = "https://github.com/stackabletech/operator-rs.git", tag = "stackable-operator-0.78.0" }
 strum = { version = "0.26", features = ["derive"] }
 socket2 = { version = "0.5", features = ["all"] }
 tokio = { version = "1.40", features = ["full"] }
@@ -31,5 +31,6 @@ tonic-build = "0.12"
 tonic-reflection = "0.12"
 tracing = "0.1.40"
 
-# [patch."https://github.com/stackabletech/operator-rs.git"]
-# stackable-operator = { git = "https://github.com/stackabletech//operator-rs.git", branch = "main" }
+[patch."https://github.com/stackabletech/operator-rs.git"]
+# stackable-operator = { path = "../operator-rs/crates/stackable-operator" }
+stackable-operator = { git = "https://github.com/stackabletech//operator-rs.git", branch = "main" }

Cargo.nix

@@ -24,6 +24,16 @@ spec:
             spec:
               description: Defines a policy for how [Listeners](https://docs.stackable.tech/home/nightly/listener-operator/listener) should be exposed. Read the [ListenerClass documentation](https://docs.stackable.tech/home/nightly/listener-operator/listenerclass) for more information.
               properties:
+                preferredAddressType:
+                  default: Hostname
+                  description: |-
+                    Whether addresses should prefer using the IP address (`IP`) or the hostname (`Hostname`).
+
+                    The other type will be used if the preferred type is not available. By default `Hostname` is used.
+                  enum:
+                    - Hostname
+                    - IP
+                  type: string
                 serviceAnnotations:
                   additionalProperties:
                     type: string

Cargo.toml

@@ -30,6 +30,7 @@ How exactly this is accomplished depends on the cloud provider in question, but
 include::example$listenerclass-internal-gke.yaml[]
 ----
 
+[#servicetype]
 == Service types
 
 The service type is defined by `ListenerClass.spec.serviceType`.
@@ -62,6 +63,24 @@ Compared to xref:#servicetype-nodeport[], this service type allows Pods to be mo
 However, it requires https://kubernetes.io/docs/concepts/services-networking/service/#loadbalancer[a cloud controller manager that supports load balancers].
 Additionally, many cloud providers charge for load-balanced traffic.
 
+[#addresstype]
+== Address types
+
+The Stackable Listener Operator supports both IP addresses and DNS hostnames. The preferred address type for a given ListenerClass can be configured using the `ListenerClass.spec.preferredAddressType` field. If no `preferredAddressType` is specified then it defaults to xref:#addresstype-hostname[].
+
+NOTE: If the preferred address type is not supported for a given environment then another type will be used.
+
+[#addresstype-ip]
+=== IP
+
+The IP address of a resource. The addresses will be less predictable (especially for xref:#servicetype-clusterip[] services),
+but does not require any special client configuration (beyond what the xref:#servicetype[] requires).
+
+[#addresstype-hostname]
+=== Hostname
+
+The DNS hostname of a resource. Clients must be able to resolve these addresses in order to connect, which may require special DNS configuration.
+
 == Default ListenerClasses
 
 The Stackable Data Platform assumes the existence of a few predefined ListenerClasses, and will use them by default as appropriate:

crate-hashes.json

@@ -8,7 +8,7 @@ use stackable_operator::{
 };
 use tonic::{Request, Response, Status};
 
-use crate::utils::error_full_message;
+use crate::utils::error::error_full_message;
 
 use super::{tonic_unimplemented, ListenerSelector, ListenerVolumeContext};
 

deploy/helm/listener-operator/crds/crds.yaml

@@ -4,8 +4,8 @@ use snafu::{OptionExt, ResultExt, Snafu};
 use stackable_operator::{
     builder::meta::OwnerReferenceBuilder,
     commons::listener::{
-        Listener, ListenerIngress, ListenerPort, ListenerSpec, PodListener, PodListenerScope,
-        PodListeners, PodListenersSpec,
+        Listener, ListenerClass, ListenerIngress, ListenerPort, ListenerSpec, PodListener,
+        PodListenerScope, PodListeners, PodListenersSpec,
     },
     k8s_openapi::api::core::v1::{Node, PersistentVolume, PersistentVolumeClaim, Pod, Volume},
     kube::{
@@ -21,7 +21,7 @@ use crate::{
         listener_mounted_pod_label, listener_persistent_volume_label, ListenerMountedPodLabelError,
         ListenerPersistentVolumeLabelError,
     },
-    utils::{error_full_message, node_primary_address},
+    utils::{address::node_primary_addresses, error::error_full_message},
 };
 
 use super::{tonic_unimplemented, ListenerSelector, ListenerVolumeContext};
@@ -72,6 +72,9 @@ enum PublishVolumeError {
         listener: ObjectRef<Listener>,
     },
 
+    #[snafu(display("{listener} has no associated ListenerClass"))]
+    ListenerHasNoClass { listener: ObjectRef<Listener> },
+
     #[snafu(display("{pod} has not been scheduled to a node yet"))]
     PodHasNoNode { pod: ObjectRef<Pod> },
 
@@ -131,6 +134,7 @@ impl From<PublishVolumeError> for Status {
             PublishVolumeError::PodHasNoNode { .. } => Status::unavailable(full_msg),
             PublishVolumeError::ListenerPvReference { .. } => Status::failed_precondition(full_msg),
             PublishVolumeError::ListenerPodSelector { .. } => Status::failed_precondition(full_msg),
+            PublishVolumeError::ListenerHasNoClass { .. } => Status::failed_precondition(full_msg),
             PublishVolumeError::BuildListenerOwnerRef { .. } => Status::unavailable(full_msg),
             PublishVolumeError::ApplyListener { .. } => Status::unavailable(full_msg),
             PublishVolumeError::AddListenerLabelToPv { .. } => Status::unavailable(full_msg),
@@ -442,10 +446,25 @@ async fn local_listener_addresses_for_pod(
             .get::<Node>(node_name, &())
             .await
             .with_context(|_| GetObjectSnafu {
-                obj: { ObjectRef::<Node>::new(node_name).erase() },
+                obj: ObjectRef::<Node>::new(node_name).erase(),
+            })?;
+        let listener_class_name =
+            listener
+                .spec
+                .class_name
+                .as_deref()
+                .with_context(|| ListenerHasNoClassSnafu {
+                    listener: ObjectRef::from_obj(listener),
+                })?;
+        let listener_class = client
+            .get::<ListenerClass>(listener_class_name, &())
+            .await
+            .with_context(|_| GetObjectSnafu {
+                obj: ObjectRef::<ListenerClass>::new(listener_class_name).erase(),
             })?;
 
-        Ok(node_primary_address(&node)
+        Ok(node_primary_addresses(&node)
+            .pick(listener_class.spec.preferred_address_type)
             .map(|(address, address_type)| ListenerIngress {
                 // nodes: Some(vec![node_name.to_string()]),
                 address: address.to_string(),