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Merged
merged 10 commits into from
Aug 13, 2025
Merged

Attach additional volume for postgres #4210

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0f1cf63
Add additional volume for postgres pods
benjaminjb Jul 17, 2025
3e24547
Add initcontainer case to tests
benjaminjb Aug 7, 2025
11e9c6c
Add assert to KUTTL
benjaminjb Aug 7, 2025
91939e6
Update name limit
benjaminjb Aug 12, 2025
a7ea055
Issue event for missing containers
benjaminjb Aug 12, 2025
4901e18
Fix test
benjaminjb Aug 12, 2025
cedf6b4
PR feedback
benjaminjb Aug 13, 2025
2c8a40e
Update internal/controller/postgrescluster/instance.go
benjaminjb Aug 13, 2025
0971139
Allow no containers
benjaminjb Aug 13, 2025
b4e667a
Alphabetize
benjaminjb Aug 13, 2025
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88 changes: 88 additions & 0 deletions config/crd/bases/postgres-operator.crunchydata.com_postgresclusters.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -11027,6 +11027,50 @@ spec:
type: array
volumes:
properties:
additional:
description: Additional pre-existing volumes to add to the
pod.
items:
properties:
claimName:
description: A reference to a preexisting PVC.
maxLength: 253
minLength: 1
pattern: ^[a-z0-9]([-a-z0-9]*[a-z0-9])?([.][a-z0-9]([-a-z0-9]*[a-z0-9])?)*$
type: string
containers:
description: |-
The containers to attach this volume to.
An omitted `Containers` field matches all containers.
An empty `Containers` field matches no containers.
items:
type: string
maxItems: 10
type: array
x-kubernetes-list-type: atomic
name:
allOf:
- maxLength: 63
- maxLength: 55
description: |-
The name of the volume used for mounting path.
Volumes are mounted in the pods at `volumes/<NAME>`
Must be unique.
minLength: 1
pattern: ^[a-z0-9]([-a-z0-9]*[a-z0-9])?$
type: string
readOnly:
description: Sets the write/read mode of the volume
type: boolean
required:
- claimName
- name
type: object
maxItems: 10
type: array
x-kubernetes-list-map-keys:
- name
x-kubernetes-list-type: map
temp:
description: |-
An ephemeral volume for temporary files.
Expand Down Expand Up @@ -29598,6 +29642,50 @@ spec:
type: array
volumes:
properties:
additional:
description: Additional pre-existing volumes to add to the
pod.
items:
properties:
claimName:
description: A reference to a preexisting PVC.
maxLength: 253
minLength: 1
pattern: ^[a-z0-9]([-a-z0-9]*[a-z0-9])?([.][a-z0-9]([-a-z0-9]*[a-z0-9])?)*$
type: string
containers:
description: |-
The containers to attach this volume to.
An omitted `Containers` field matches all containers.
An empty `Containers` field matches no containers.
items:
type: string
maxItems: 10
type: array
x-kubernetes-list-type: atomic
name:
allOf:
- maxLength: 63
- maxLength: 55
description: |-
The name of the volume used for mounting path.
Volumes are mounted in the pods at `volumes/<NAME>`
Must be unique.
minLength: 1
pattern: ^[a-z0-9]([-a-z0-9]*[a-z0-9])?$
type: string
readOnly:
description: Sets the write/read mode of the volume
type: boolean
required:
- claimName
- name
type: object
maxItems: 10
type: array
x-kubernetes-list-map-keys:
- name
x-kubernetes-list-type: map
temp:
description: |-
An ephemeral volume for temporary files.
Expand Down
10 changes: 10 additions & 0 deletions internal/controller/postgrescluster/instance.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1253,6 +1253,16 @@ func (r *Reconciler) reconcileInstance(
addDevSHM(&instance.Spec.Template)
}

// mount additional volumes to the Postgres instance containers
if err == nil && spec.Volumes != nil && len(spec.Volumes.Additional) > 0 {
missingContainers := addAdditionalVolumesToSpecifiedContainers(&instance.Spec.Template, spec.Volumes.Additional)

if len(missingContainers) > 0 {
r.Recorder.Eventf(cluster, corev1.EventTypeWarning, "SpecifiedContainerNotFound",
"The following containers were specified for additional volumes but cannot be found: %s.", missingContainers)
}
}

if err == nil {
err = errors.WithStack(r.apply(ctx, instance))
}
Expand Down
80 changes: 80 additions & 0 deletions internal/controller/postgrescluster/util.go
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Original file line number Diff line number Diff line change
Expand Up @@ -13,9 +13,11 @@ import (
corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/api/resource"
"k8s.io/apimachinery/pkg/util/rand"
"k8s.io/apimachinery/pkg/util/sets"

"github.com/crunchydata/postgres-operator/internal/initialize"
"github.com/crunchydata/postgres-operator/internal/naming"
"github.com/crunchydata/postgres-operator/pkg/apis/postgres-operator.crunchydata.com/v1beta1"
)

var tmpDirSizeLimit = resource.MustParse("16Mi")
Expand Down Expand Up @@ -285,3 +287,81 @@ func safeHash32(content func(w io.Writer) error) (string, error) {
}
return rand.SafeEncodeString(fmt.Sprint(hash.Sum32())), nil
}

// AdditionalVolumeMount returns the name and mount path of the additional volume.
func AdditionalVolumeMount(name string, readOnly bool) corev1.VolumeMount {
return corev1.VolumeMount{
Name: fmt.Sprintf("volumes-%s", name),
MountPath: "/volumes/" + name,
ReadOnly: readOnly,
}
}

// addAdditionalVolumesToSpecifiedContainers adds additional volumes to the specified
// containers in the specified pod
// addAdditionalVolumesToSpecifiedContainers adds the volumes to the pod
// as `volumes-<additionalVolumeRequest.Name>`
// and adds the directory to the path `/volumes/<additionalVolumeRequest.Name>`
func addAdditionalVolumesToSpecifiedContainers(template *corev1.PodTemplateSpec,
additionalVolumes []v1beta1.AdditionalVolume) []string {

missingContainers := []string{}
for _, additionalVolumeRequest := range additionalVolumes {

additionalVolumeMount := AdditionalVolumeMount(
additionalVolumeRequest.Name,
additionalVolumeRequest.ReadOnly,
)

additionalVolume := corev1.Volume{
Name: additionalVolumeMount.Name,
VolumeSource: corev1.VolumeSource{
PersistentVolumeClaim: &corev1.PersistentVolumeClaimVolumeSource{
ClaimName: additionalVolumeRequest.ClaimName,
ReadOnly: additionalVolumeMount.ReadOnly,
},
},
}

// Create a set of all the requested containers,
// then in the loops below when we attach the volume to a container,
// we can safely remove that container name from the set.
// This gives us a way to track the containers that are requested but not found.
// This relies on `containers` and `initContainers` together being unique.
// - https://github.com/kubernetes/api/blob/b40c1cacbb902b21a7e0c7bf0967321860c1a632/core/v1/types.go#L3895C27-L3896C33
names := sets.New(additionalVolumeRequest.Containers...)
allContainers := false
// If the containers list is omitted, we add the volume to all containers
if additionalVolumeRequest.Containers == nil {
allContainers = true
}

for i := range template.Spec.Containers {
if allContainers || names.Has(template.Spec.Containers[i].Name) {
template.Spec.Containers[i].VolumeMounts = append(
template.Spec.Containers[i].VolumeMounts,
additionalVolumeMount)

names.Delete(template.Spec.Containers[i].Name)
}
}

for i := range template.Spec.InitContainers {
if allContainers || names.Has(template.Spec.InitContainers[i].Name) {
template.Spec.InitContainers[i].VolumeMounts = append(
template.Spec.InitContainers[i].VolumeMounts,
additionalVolumeMount)

names.Delete(template.Spec.InitContainers[i].Name)

}
}

missingContainers = append(missingContainers, names.UnsortedList()...)
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💭 Using Delete to subtract from names relies on init and regular containers having unique names together. That's correct and fine, but I wonder if it is worth calling out.

🤔 Should the resulting slice be a Set?

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I was about to raise this concern myself... Is it correct though, when you take sidecars into consideration? Couldn't the user add a sidecar to Containers that has the same name as one in InitContainers?

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Answering my own question: No, the user could not add a sidecar with the same name as an init container. Ben tried it out and the Pod fails to roll out. He also found this in k8s documentation: “The name of each app and init container in a Pod must be unique; a validation error is thrown for any container sharing a name with another.”


template.Spec.Volumes = append(
template.Spec.Volumes,
additionalVolume)
}
return missingContainers
}
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