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Add shm_volume option (#427)

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Add possibility to mount a tmpfs volume to /dev/shm to avoid issues like
[this](https://github.com/docker-library/postgres/issues/416). To achieve that
two new options were introduced:

* `enableShmVolume` to PostgreSQL manifest, to specify whether or not mount
this volume per database cluster

* `enable_shm_volume` to operator configuration, to specify whether or not mount
per operator.

The first one, `enableShmVolume` takes precedence to allow us to be more flexible.
This commit is contained in:
Dmitry Dolgov
2018-12-21 16:22:30 +01:00
committed by GitHub
parent ff5c63ddf1
commit d6e6b00770
10 changed files with 137 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files
pkg/apis/acid.zalan.do/v1/postgresql_type.go
+1
View File
@@ -51,6 +51,7 @@ type PostgresSpec struct {
Tolerations []v1.Toleration `json:"tolerations,omitempty"`
Sidecars []Sidecar `json:"sidecars,omitempty"`
PodPriorityClassName string `json:"pod_priority_class_name,omitempty"`
ShmVolume *bool `json:"enableShmVolume,omitempty"`
}
// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
pkg/apis/acid.zalan.do/v1/util_test.go
+3 -3
View File
@@ -499,7 +499,7 @@ func TestMarshal(t *testing.T) {
t.Errorf("Marshal error: %v", err)
}
if !bytes.Equal(m, tt.marshal) {
t.Errorf("Marshal Postgresql expected: %q, got: %q", string(tt.marshal), string(m))
t.Errorf("Marshal Postgresql \nexpected: %q, \ngot: %q", string(tt.marshal), string(m))
}
}
}
@@ -507,11 +507,11 @@ func TestMarshal(t *testing.T) {
func TestPostgresMeta(t *testing.T) {
for _, tt := range unmarshalCluster {
if a := tt.out.GetObjectKind(); a != &tt.out.TypeMeta {
t.Errorf("GetObjectKindMeta expected: %v, got: %v", tt.out.TypeMeta, a)
t.Errorf("GetObjectKindMeta \nexpected: %v, \ngot: %v", tt.out.TypeMeta, a)
}
if a := tt.out.GetObjectMeta(); reflect.DeepEqual(a, tt.out.ObjectMeta) {
t.Errorf("GetObjectMeta expected: %v, got: %v", tt.out.ObjectMeta, a)
t.Errorf("GetObjectMeta \nexpected: %v, \ngot: %v", tt.out.ObjectMeta, a)
}
}
}
pkg/cluster/k8sres.go
+50 -2
View File
@@ -18,6 +18,7 @@ import (
acidv1 "github.com/zalando-incubator/postgres-operator/pkg/apis/acid.zalan.do/v1"
"github.com/zalando-incubator/postgres-operator/pkg/spec"
"github.com/zalando-incubator/postgres-operator/pkg/util"
"github.com/zalando-incubator/postgres-operator/pkg/util/config"
"github.com/zalando-incubator/postgres-operator/pkg/util/constants"
"k8s.io/apimachinery/pkg/labels"
)
@@ -396,6 +397,16 @@ func generateSidecarContainers(sidecars []acidv1.Sidecar,
return nil, nil
}
// Check whether or not we're requested to mount an shm volume,
// taking into account that PostgreSQL manifest has precedence.
func mountShmVolumeNeeded(opConfig config.Config, pgSpec *acidv1.PostgresSpec) bool {
if pgSpec.ShmVolume != nil {
return *pgSpec.ShmVolume
}
return opConfig.ShmVolume
}
func generatePodTemplate(
namespace string,
labels labels.Set,
@@ -407,6 +418,7 @@ func generatePodTemplate(
podServiceAccountName string,
kubeIAMRole string,
priorityClassName string,
shmVolume bool,
) (*v1.PodTemplateSpec, error) {
terminateGracePeriodSeconds := terminateGracePeriod
@@ -420,6 +432,10 @@ func generatePodTemplate(
Tolerations: *tolerationsSpec,
}
if shmVolume {
addShmVolume(&podSpec)
}
if nodeAffinity != nil {
podSpec.Affinity = nodeAffinity
}
@@ -733,7 +749,12 @@ func (c *Cluster) generateStatefulSet(spec *acidv1.PostgresSpec) (*v1beta1.State
volumeMounts := generateVolumeMounts()
// generate the spilo container
spiloContainer := generateSpiloContainer(c.containerName(), &effectiveDockerImage, resourceRequirements, spiloEnvVars, volumeMounts)
spiloContainer := generateSpiloContainer(c.containerName(),
&effectiveDockerImage,
resourceRequirements,
spiloEnvVars,
volumeMounts,
)
// resolve conflicts between operator-global and per-cluster sidecards
sideCars := c.mergeSidecars(spec.Sidecars)
@@ -775,7 +796,8 @@ func (c *Cluster) generateStatefulSet(spec *acidv1.PostgresSpec) (*v1beta1.State
int64(c.OpConfig.PodTerminateGracePeriod.Seconds()),
c.OpConfig.PodServiceAccountName,
c.OpConfig.KubeIAMRole,
effectivePodPriorityClassName); err != nil {
effectivePodPriorityClassName,
mountShmVolumeNeeded(c.OpConfig, spec)); err != nil {
return nil, fmt.Errorf("could not generate pod template: %v", err)
}
@@ -882,6 +904,32 @@ func (c *Cluster) getNumberOfInstances(spec *acidv1.PostgresSpec) int32 {
return newcur
}
// To avoid issues with limited /dev/shm inside docker environment, when
// PostgreSQL can't allocate enough of dsa segments from it, we can
// mount an extra memory volume
//
// see https://docs.okd.io/latest/dev_guide/shared_memory.html
func addShmVolume(podSpec *v1.PodSpec) {
volumes := append(podSpec.Volumes, v1.Volume{
Name: constants.ShmVolumeName,
VolumeSource: v1.VolumeSource{
EmptyDir: &v1.EmptyDirVolumeSource{
Medium: "Memory",
},
},
})
pgIdx := constants.PostgresContainerIdx
mounts := append(podSpec.Containers[pgIdx].VolumeMounts,
v1.VolumeMount{
Name: constants.ShmVolumeName,
MountPath: constants.ShmVolumePath,
})
podSpec.Containers[0].VolumeMounts = mounts
podSpec.Volumes = volumes
}
func generatePersistentVolumeClaimTemplate(volumeSize, volumeStorageClass string) (*v1.PersistentVolumeClaim, error) {
var storageClassName *string
pkg/cluster/k8sres_test.go
+54
View File
@@ -1,8 +1,11 @@
package cluster
import (
"k8s.io/api/core/v1"
acidv1 "github.com/zalando-incubator/postgres-operator/pkg/apis/acid.zalan.do/v1"
"github.com/zalando-incubator/postgres-operator/pkg/util/config"
"github.com/zalando-incubator/postgres-operator/pkg/util/constants"
"github.com/zalando-incubator/postgres-operator/pkg/util/k8sutil"
"testing"
)
@@ -75,3 +78,54 @@ func TestCreateLoadBalancerLogic(t *testing.T) {
}
}
}
func TestShmVolume(t *testing.T) {
testName := "TestShmVolume"
tests := []struct {
subTest string
podSpec *v1.PodSpec
shmPos int
}{
{
subTest: "empty PodSpec",
podSpec: &v1.PodSpec{
Volumes: []v1.Volume{},
Containers: []v1.Container{
v1.Container{
VolumeMounts: []v1.VolumeMount{},
},
},
},
shmPos: 0,
},
{
subTest: "non empty PodSpec",
podSpec: &v1.PodSpec{
Volumes: []v1.Volume{v1.Volume{}},
Containers: []v1.Container{
v1.Container{
VolumeMounts: []v1.VolumeMount{
v1.VolumeMount{},
},
},
},
},
shmPos: 1,
},
}
for _, tt := range tests {
addShmVolume(tt.podSpec)
volumeName := tt.podSpec.Volumes[tt.shmPos].Name
volumeMountName := tt.podSpec.Containers[0].VolumeMounts[tt.shmPos].Name
if volumeName != constants.ShmVolumeName {
t.Errorf("%s %s: Expected volume %s was not created, have %s instead",
testName, tt.subTest, constants.ShmVolumeName, volumeName)
}
if volumeMountName != constants.ShmVolumeName {
t.Errorf("%s %s: Expected mount %s was not created, have %s instead",
testName, tt.subTest, constants.ShmVolumeName, volumeMountName)
}
}
}
pkg/util/config/config.go
+1
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@@ -38,6 +38,7 @@ type Resources struct {
NodeReadinessLabel map[string]string `name:"node_readiness_label" default:""`
MaxInstances int32 `name:"max_instances" default:"-1"`
MinInstances int32 `name:"min_instances" default:"-1"`
ShmVolume bool `name:"enable_shm_volume" default:"true"`
}
// Auth describes authentication specific configuration parameters
pkg/util/constants/kubernetes.go
+1
View File
@@ -5,6 +5,7 @@ import "time"
// General kubernetes-related constants
const (
PostgresContainerName = "postgres"
PostgresContainerIdx = 0
K8sAPIPath = "/apis"
StatefulsetDeletionInterval = 1 * time.Second
StatefulsetDeletionTimeout = 30 * time.Second
pkg/util/constants/postgresql.go
+3
View File
@@ -10,4 +10,7 @@ const (
PostgresConnectRetryTimeout = 2 * time.Minute
PostgresConnectTimeout = 15 * time.Second
ShmVolumeName = "dshm"
ShmVolumePath = "/dev/shm"
)