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feat: add option to override default kubernetes scheduler (#2013)
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Add the `.spec.schedulerName` field to specify what scheduler should dispatch
the Cluster pods.

This patch ensures that we trigger a rollout of the pods when the scheduler changes;
the only limitation is that no rollout will be started by setting the field empty.

Signed-off-by: adrixop95 <adrixop95@me.com>
Signed-off-by: Philippe Scorsolini <p.scorsolini@gmail.com>
Signed-off-by: Armando Ruocco <armando.ruocco@enterprisedb.com>
Signed-off-by: Marco Nenciarini <marco.nenciarini@enterprisedb.com>
Co-authored-by: Philippe Scorsolini <p.scorsolini@gmail.com>
Co-authored-by: Armando Ruocco <armando.ruocco@enterprisedb.com>
Co-authored-by: Marco Nenciarini <marco.nenciarini@enterprisedb.com>
(cherry picked from commit 50113b8)
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@Adrixop95
Adrixop95 committed May 18, 2023
1 parent 5ccaf07 commit b657b42
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Showing 8 changed files with 55 additions and 7 deletions.
7 changes: 7 additions & 0 deletions api/v1/cluster_types.go
View file
Expand Up @@ -135,6 +135,13 @@ type ClusterSpec struct {
// +optional
ImagePullPolicy corev1.PullPolicy `json:"imagePullPolicy,omitempty"`

// If specified, the pod will be dispatched by specified Kubernetes
// scheduler. If not specified, the pod will be dispatched by the default
// scheduler. More info:
// https://kubernetes.io/docs/concepts/scheduling-eviction/kube-scheduler/
// +optional
SchedulerName string `json:"schedulerName,omitempty"`

// The UID of the `postgres` user inside the image, defaults to `26`
// +kubebuilder:default:=26
PostgresUID int64 `json:"postgresUID,omitempty"`
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5 changes: 5 additions & 0 deletions config/crd/bases/postgresql.cnpg.io_clusters.yaml
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Expand Up @@ -2852,6 +2852,11 @@ spec:
to an implementation-defined value. More info: https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/'
type: object
type: object
schedulerName:
description: 'If specified, the pod will be dispatched by specified
Kubernetes scheduler. If not specified, the pod will be dispatched
by the default scheduler. More info: https://kubernetes.io/docs/concepts/scheduling-eviction/kube-scheduler/'
type: string
seccompProfile:
description: 'The SeccompProfile applied to every Pod and Container.
Defaults to: `RuntimeDefault`'
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18 changes: 18 additions & 0 deletions controllers/cluster_upgrade.go
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Expand Up @@ -286,6 +286,10 @@ func IsPodNeedingRollout(status postgres.PostgresqlStatus, cluster *apiv1.Cluste
return true, false, reason
}

if restartRequired, reason := isPodNeedingUpdatedScheduler(cluster, status.Pod); restartRequired {
return restartRequired, false, reason
}

// Detect changes in the postgres container configuration
for _, container := range status.Pod.Spec.Containers {
// we go to the next array element if it isn't the postgres container
Expand All @@ -306,6 +310,20 @@ func IsPodNeedingRollout(status postgres.PostgresqlStatus, cluster *apiv1.Cluste
true, "configuration needs a restart to apply some configuration changes"
}

// isPodNeedingUpdatedScheduler returns a boolean indicating if a restart is required and the relative message
func isPodNeedingUpdatedScheduler(cluster *apiv1.Cluster, pod corev1.Pod) (bool, string) {
if cluster.Spec.SchedulerName == "" || cluster.Spec.SchedulerName == pod.Spec.SchedulerName {
return false, ""
}

message := fmt.Sprintf(
"scheduler name changed from: '%s', to '%s'",
pod.Spec.SchedulerName,
cluster.Spec.SchedulerName,
)
return true, message
}

func isPodNeedingUpdateOfProjectedVolume(cluster *apiv1.Cluster, pod corev1.Pod) (needsUpdate bool, reason string) {
currentProjectedVolumeConfiguration := getProjectedVolumeConfigurationFromPod(pod)

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24 changes: 19 additions & 5 deletions controllers/cluster_upgrade_test.go
View file
Expand Up @@ -28,11 +28,16 @@ import (
)

var _ = Describe("Pod upgrade", func() {
cluster := apiv1.Cluster{
Spec: apiv1.ClusterSpec{
ImageName: "postgres:13.0",
},
}
var cluster apiv1.Cluster

BeforeEach(func() {
cluster = apiv1.Cluster{
Spec: apiv1.ClusterSpec{
ImageName: "postgres:13.0",
},
}
})

It("will not require a restart for just created Pods", func() {
pod := specs.PodWithExistingStorage(cluster, 1)
Expect(isPodNeedingRestart(&cluster, postgres.PostgresqlStatus{Pod: *pod})).
Expand Down Expand Up @@ -93,6 +98,15 @@ var _ = Describe("Pod upgrade", func() {
Expect(reason).To(BeEquivalentTo("configuration needs a restart to apply some configuration changes"))
})

It("should trigger a rollout when the scheduler changes", func() {
pod := specs.PodWithExistingStorage(cluster, 1)
cluster.Spec.SchedulerName = "newScheduler"

rollout, reason := isPodNeedingUpdatedScheduler(&cluster, *pod)
Expect(rollout).To(BeTrue())
Expect(reason).ToNot(BeEmpty())
})

When("there's a custom environment variable set", func() {
It("detects when a new custom environment variable is set", func() {
pod := specs.PodWithExistingStorage(cluster, 1)
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1 change: 1 addition & 0 deletions docs/src/api_reference.md
View file
Expand Up @@ -360,6 +360,7 @@ Name | Description
`inheritedMetadata ` | Metadata that will be inherited by all objects related to the Cluster | [*EmbeddedObjectMetadata](#EmbeddedObjectMetadata)
`imageName ` | Name of the container image, supporting both tags (`<image>:<tag>`) and digests for deterministic and repeatable deployments (`<image>:<tag>@sha256:<digestValue>`) | string
`imagePullPolicy ` | Image pull policy. One of `Always`, `Never` or `IfNotPresent`. If not defined, it defaults to `IfNotPresent`. Cannot be updated. More info: https://kubernetes.io/docs/concepts/containers/images#updating-images | corev1.PullPolicy
`schedulerName ` | If specified, the pod will be dispatched by specified Kubernetes scheduler. If not specified, the pod will be dispatched by the default scheduler. More info: https://kubernetes.io/docs/concepts/scheduling-eviction/kube-scheduler/ | string
`postgresUID ` | The UID of the `postgres` user inside the image, defaults to `26` | int64
`postgresGID ` | The GID of the `postgres` user inside the image, defaults to `26` | int64
`instances ` | Number of instances required in the cluster - *mandatory* | int
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1 change: 1 addition & 0 deletions internal/cmd/plugin/pgbench/pgbench.go
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Expand Up @@ -161,6 +161,7 @@ func (cmd *pgBenchCommand) buildJob(cluster apiv1.Cluster) *batchv1.Job {
},
},
},
SchedulerName: cluster.Spec.SchedulerName,
Containers: []corev1.Container{
{
Name: "pgbench",
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1 change: 1 addition & 0 deletions pkg/specs/jobs.go
View file
Expand Up @@ -271,6 +271,7 @@ func createPrimaryJob(cluster apiv1.Cluster, nodeSerial int, role jobRole, initC
InitContainers: []corev1.Container{
createBootstrapContainer(cluster),
},
SchedulerName: cluster.Spec.SchedulerName,
Containers: []corev1.Container{
{
Name: string(role),
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5 changes: 3 additions & 2 deletions pkg/specs/pods.go
View file
Expand Up @@ -352,8 +352,9 @@ func PodWithExistingStorage(cluster apiv1.Cluster, nodeSerial int) *corev1.Pod {
InitContainers: []corev1.Container{
createBootstrapContainer(cluster),
},
Containers: createPostgresContainers(cluster, envConfig),
Volumes: createPostgresVolumes(cluster, podName),
SchedulerName: cluster.Spec.SchedulerName,
Containers: createPostgresContainers(cluster, envConfig),
Volumes: createPostgresVolumes(cluster, podName),
SecurityContext: CreatePodSecurityContext(
cluster.GetSeccompProfile(),
cluster.GetPostgresUID(),
Expand Down

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