Use cluster UID as a suffix to the WAL bucket. (zalando#211)

Avoid reusing WAL S3 buckets of the older cluster with the same name as the existing one.

For the new cluster, the S3 bucket name will include a suffix that is equal to the UID of the PostgreSQL object describing the cluster. That way, the bucket name will stay the same for all members iff  they correspond to the same PostgreSQL cluster object.

When "clone: uid:" key is present in the cluster manifest and the cluster is cloned from an S3 bucket (currently that happens if the endTimestamp is present in the clone description) the S3 bucket to clone from is suffixed with the -uid value.

Author: alexeyklyukin

pkg/cluster/k8sres.go

@@ -7,6 +7,7 @@ import (
 
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/intstr"
 	"k8s.io/client-go/pkg/api/v1"
 	"k8s.io/client-go/pkg/apis/apps/v1beta1"
@@ -280,6 +281,7 @@ func (c *Cluster) tolerations(tolerationsSpec *[]v1.Toleration) []v1.Toleration
 }
 
 func (c *Cluster) generatePodTemplate(
+	uid types.UID,
 	resourceRequirements *v1.ResourceRequirements,
 	resourceRequirementsScalyrSidecar *v1.ResourceRequirements,
 	tolerationsSpec *[]v1.Toleration,
@@ -358,6 +360,7 @@ func (c *Cluster) generatePodTemplate(
 	}
 	if c.OpConfig.WALES3Bucket != "" {
 		envVars = append(envVars, v1.EnvVar{Name: "WAL_S3_BUCKET", Value: c.OpConfig.WALES3Bucket})
+		envVars = append(envVars, v1.EnvVar{Name: "WAL_BUCKET_SCOPE_SUFFIX", Value: getWALBucketScopeSuffix(string(uid))})
 	}
 
 	if c.OpConfig.EtcdHost == "" {
@@ -500,6 +503,13 @@ func (c *Cluster) generatePodTemplate(
 	return &template
 }
 
+func getWALBucketScopeSuffix(uid string) string {
+	if uid != "" {
+		return fmt.Sprintf("-%s", uid)
+	}
+	return ""
+}
+
 func makeResources(cpuRequest, memoryRequest, cpuLimit, memoryLimit string) spec.Resources {
 	return spec.Resources{
 		ResourceRequest: spec.ResourceDescription{
@@ -537,7 +547,7 @@ func (c *Cluster) generateStatefulSet(spec *spec.PostgresSpec) (*v1beta1.Statefu
 			customPodEnvVars = cm.Data
 		}
 	}
-	podTemplate := c.generatePodTemplate(resourceRequirements, resourceRequirementsScalyrSidecar, &spec.Tolerations, &spec.PostgresqlParam, &spec.Patroni, &spec.Clone, &spec.DockerImage, customPodEnvVars)
+	podTemplate := c.generatePodTemplate(c.Postgresql.GetUID(), resourceRequirements, resourceRequirementsScalyrSidecar, &spec.Tolerations, &spec.PostgresqlParam, &spec.Patroni, &spec.Clone, &spec.DockerImage, customPodEnvVars)
 	volumeClaimTemplate, err := generatePersistentVolumeClaimTemplate(spec.Volume.Size, spec.Volume.StorageClass)
 	if err != nil {
 		return nil, fmt.Errorf("could not generate volume claim template: %v", err)
@@ -757,6 +767,7 @@ func (c *Cluster) generateCloneEnvironment(description *spec.CloneDescription) [
 		result = append(result, v1.EnvVar{Name: "CLONE_METHOD", Value: "CLONE_WITH_WALE"})
 		result = append(result, v1.EnvVar{Name: "CLONE_WAL_S3_BUCKET", Value: c.OpConfig.WALES3Bucket})
 		result = append(result, v1.EnvVar{Name: "CLONE_TARGET_TIME", Value: description.EndTimestamp})
+		result = append(result, v1.EnvVar{Name: "CLONE_WAL_BUCKET_SCOPE_SUFFIX", Value: getWALBucketScopeSuffix(description.Uid)})
 	}
 
 	return result

pkg/spec/postgresql.go

@@ -55,6 +55,7 @@ type Patroni struct {
 // CloneDescription describes which cluster the new should clone and up to which point in time
 type CloneDescription struct {
 	ClusterName  string `json:"cluster,omitempty"`
+	Uid          string `json:"uid,omitempty"`
 	EndTimestamp string `json:"timestamp,omitempty"`
 }