Issue 63: Added support for ephemeral storage

README.md

@@ -11,6 +11,7 @@ The project is currently alpha. While no breaking API changes are currently plan
  * [Usage](#usage)    
     * [Installation of the Operator](#install-the-operator)
     * [Deploy a sample Zookeeper Cluster](#deploy-a-sample-zookeeper-cluster)
+    * [Deploy a sample ZooKeeper Cluster with Ephemeral Storage](#Deploy-a-sample-zookeeper-cluster-with-ephemeral-storage)
     * [Deploy a sample Zookeeper Cluster to a cluster using Istio](#deploy-a-sample-zookeeper-cluster-with-istio)
     * [Upgrade a Zookeeper Cluster](#upgrade-a-zookeeper-cluster)
     * [Uninstall the Zookeeper Cluster](#uninstall-the-zookeeper-cluster)
@@ -155,6 +156,38 @@ svc/zookeeper-client     ClusterIP   10.31.243.173   <none>        2181/TCP
 svc/zookeeper-headless   ClusterIP   None            <none>        2888/TCP,3888/TCP   2m
 ```
 
+### Deploy a sample Zookeeper cluster with Ephemeral storage
+
+Create a Yaml file called `zk.yaml` with the following content to install a 3-node Zookeeper cluster.
+
+```yaml
+apiVersion: "zookeeper.pravega.io/v1beta1"
+kind: "ZookeeperCluster"
+metadata:
+  name: "example"
+spec:
+  replicas: 3        
+  storageType: ephemeral
+```
+
+```
+$ kubectl create -f zk.yaml
+```
+
+After a couple of minutes, all cluster members should become ready.
+
+```
+$ kubectl get zk
+
+NAME      REPLICAS   READY REPLICAS   VERSION   DESIRED VERSION   INTERNAL ENDPOINT    EXTERNAL ENDPOINT   AGE
+example   3          3                 0.2.7     0.2.7             10.100.200.18:2181   N/A                 94s
+```
+>Note: User should only provide value for either the field persistence or ephemeral in the spec if none of the values is specified default is persistence
+
+>Note: In case of ephemeral storage, the cluster may not be able to come back up if more than quorum number of nodes are restarted simultaneously.
+
+>Note: In case of ephemeral storage, there will be loss of data when the node gets restarted.
+
 ### Deploy a sample Zookeeper cluster with Istio
 Create a Yaml file called `zk-with-istio.yaml` with the following content to install a 3-node Zookeeper cluster.
 

charts/zookeeper/README.md

@@ -59,6 +59,9 @@ The following table lists the configurable parameters of the Zookeeper chart and
 | `config.tickTime` | Length of a single tick which is the basic time unit used by Zookeeper (measured in milliseconds) | `2000` |
 | `config.syncLimit` | Amount of time (in ticks) to allow followers to sync with Zookeeper | `2` |
 | `config.quorumListenOnAllIPs` | Whether Zookeeper server will listen for connections from its peers on all available IP addresses | `false` |
+| `storageType` | Type of storage that can be used it can take either ephemeral or persistence as value | `persistence` |
 | `persistence.reclaimPolicy` | Reclaim policy for persistent volumes | `Delete` |
 | `persistence.storageClassName` | Storage class for persistent volumes | `standard` |
 | `persistence.volumeSize` | Size of the volume requested for persistent volumes | `20Gi` |
+| `ephemeral.emptydirvolumesource.medium` |  What type of storage medium should back the directory. | `""` |
+| `ephemeral.emptydirvolumesource.sizeLimit` | Total amount of local storage required for the EmptyDir volume. | |

charts/zookeeper/templates/zookeeper.yaml

@@ -43,10 +43,22 @@ spec:
     syncLimit: {{ .Values.config.syncLimit }}
     quorumListenOnAllIPs: {{ .Values.config.quorumListenOnAllIPs }}
   {{- end }}
+  storageType: {{ .Values.storageType }}
+  {{- if eq .Values.storageType "ephemeral" }}
+  ephemeral:
+    {{- if .Values.ephemeral.emptydirvolumesource }}
+    emptydirvolumesource:
+      medium: {{ .Values.ephemeral.emptydirvolumesource.medium }}
+      {{- if .Values.ephemeral.emptydirvolumesource.sizeLimit }}
+      sizeLimit: {{ .Values.ephemeral.emptydirvolumesource.sizeLimit }}
+      {{- end }}
+      {{- end }}
+  {{- else }}
   persistence:
     reclaimPolicy: {{ .Values.persistence.reclaimPolicy }}
     spec:
       storageClassName: {{ .Values.persistence.storageClassName }}
       resources:
         requests:
           storage: {{ .Values.persistence.volumeSize }}
+  {{- end }}

charts/zookeeper/values.yaml

@@ -26,13 +26,25 @@ config: {}
   # syncLimit: 2
   # quorumListenOnAllIPs: false
 
+## configure the storage type
+## accepted values : persistence/ephemeral
+## default option is persistence
+storageType: persistence
+
 persistence:
   storageClassName: standard
   ## specifying reclaim policy for PersistentVolumes
   ## accepted values - Delete / Retain
   reclaimPolicy: Delete
   volumeSize: 20Gi
 
+ephemeral:
+  emptydirvolumesource:
+    ## specifying Medium for emptydirvolumesource
+    ## accepted values - ""/Memory
+    #medium: ""
+    #sizeLimit: 20Gi
+
 hooks:
   image:
     repository: lachlanevenson/k8s-kubectl

deploy/cr/ECS/zookeeper_v1beta1_zookeepercluster_cr.yaml

@@ -0,0 +1,17 @@
+apiVersion: zookeeper.pravega.io/v1beta1
+kind: ZookeeperCluster
+metadata:
+  name: zookeeper
+spec:
+  replicas: 3
+  image:
+    repository: pravega/zookeeper
+    tag: 0.2.8
+  storageType: persistence
+  persistence:
+    reclaimPolicy: Retain
+    spec:
+      storageClassName: "standard"
+      resources:
+        requests:
+          storage: 20Gi

deploy/crds/zookeeper_v1beta1_zookeepercluster_cr.yaml → deploy/cr/pravega/zookeeper_v1beta1_zookeepercluster_cr.yaml

@@ -7,6 +7,7 @@ spec:
   image:
     repository: pravega/zookeeper
     tag: 0.2.8
+  storageType: persistence
   persistence:
     reclaimPolicy: Delete
     spec:

go.mod

@@ -10,6 +10,8 @@ require (
 	github.com/operator-framework/operator-sdk v0.17.0
 	github.com/pkg/errors v0.9.1
 	github.com/samuel/go-zookeeper v0.0.0-20190923202752-2cc03de413da
+	golang.org/x/lint v0.0.0-20191125180803-fdd1cda4f05f // indirect
+	golang.org/x/tools v0.0.0-20200331202046-9d5940d49312 // indirect
 	k8s.io/api v0.17.5
 	k8s.io/apimachinery v0.17.5
 	k8s.io/client-go v12.0.0+incompatible

go.sum

@@ -474,6 +474,7 @@ github.com/julienschmidt/httprouter v1.3.0/go.mod h1:JR6WtHb+2LUe8TCKY3cZOxFyyO8
 github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0/go.mod h1:1NbS8ALrpOvjt0rHPNLyCIeMtbizbir8U//inJ+zuB8=
 github.com/karrick/godirwalk v1.10.12/go.mod h1:RoGL9dQei4vP9ilrpETWE8CLOZ1kiN0LhBygSwrAsHA=
 github.com/kisielk/errcheck v1.1.0/go.mod h1:EZBBE59ingxPouuu3KfxchcWSUPOHkagtvWXihfKN4Q=
+github.com/kisielk/errcheck v1.2.0 h1:reN85Pxc5larApoH1keMBiu2GWtPqXQ1nc9gx+jOU+E=
 github.com/kisielk/errcheck v1.2.0/go.mod h1:/BMXB+zMLi60iA8Vv6Ksmxu/1UDYcXs4uQLJ+jE2L00=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
@@ -778,6 +779,7 @@ github.com/xlab/handysort v0.0.0-20150421192137-fb3537ed64a1/go.mod h1:QcJo0QPSf
 github.com/xlab/treeprint v0.0.0-20180616005107-d6fb6747feb6/go.mod h1:ce1O1j6UtZfjr22oyGxGLbauSBp2YVXpARAosm7dHBg=
 github.com/xordataexchange/crypt v0.0.3-0.20170626215501-b2862e3d0a77/go.mod h1:aYKd//L2LvnjZzWKhF00oedf4jCCReLcmhLdhm1A27Q=
 github.com/yuin/goldmark v1.1.25/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
+github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yvasiyarov/go-metrics v0.0.0-20140926110328-57bccd1ccd43/go.mod h1:aX5oPXxHm3bOH+xeAttToC8pqch2ScQN/JoXYupl6xs=
 github.com/yvasiyarov/gorelic v0.0.0-20141212073537-a9bba5b9ab50/go.mod h1:NUSPSUX/bi6SeDMUh6brw0nXpxHnc96TguQh0+r/ssA=
 github.com/yvasiyarov/newrelic_platform_go v0.0.0-20140908184405-b21fdbd4370f/go.mod h1:GlGEuHIJweS1mbCqG+7vt2nvWLzLLnRHbXz5JKd/Qbg=
@@ -852,6 +854,8 @@ golang.org/x/lint v0.0.0-20190409202823-959b441ac422/go.mod h1:6SW0HCj/g11FgYtHl
 golang.org/x/lint v0.0.0-20190909230951-414d861bb4ac/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
+golang.org/x/lint v0.0.0-20191125180803-fdd1cda4f05f h1:J5lckAjkw6qYlOZNj90mLYNTEKDvWeuc1yieZ8qUzUE=
+golang.org/x/lint v0.0.0-20191125180803-fdd1cda4f05f/go.mod h1:5qLYkcX4OjUUV8bRuDixDT3tpyyb+LUpUlRWLxfhWrs=
 golang.org/x/mobile v0.0.0-20190312151609-d3739f865fa6/go.mod h1:z+o9i4GpDbdi3rU15maQ/Ox0txvL9dWGYEHz965HBQE=
 golang.org/x/mobile v0.0.0-20190719004257-d2bd2a29d028/go.mod h1:E/iHnbuqvinMTCcRqshq8CkpyQDoeVncDDYHnLhea+o=
 golang.org/x/mod v0.0.0-20190513183733-4bf6d317e70e/go.mod h1:mXi4GBBbnImb6dmsKGUJ2LatrhH/nqhxcFungHvyanc=
@@ -1004,9 +1008,12 @@ golang.org/x/tools v0.0.0-20191111182352-50fa39b762bc/go.mod h1:b+2E5dAYhXwXZwtn
 golang.org/x/tools v0.0.0-20191113191852-77e3bb0ad9e7/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20191115202509-3a792d9c32b2/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20191125144606-a911d9008d1f/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20200115044656-831fdb1e1868/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
 golang.org/x/tools v0.0.0-20200327195553-82bb89366a1e h1:qCZ8SbsZMjT0OuDPCEBxgLZic4NMj8Gj4vNXiTVRAaA=
 golang.org/x/tools v0.0.0-20200327195553-82bb89366a1e/go.mod h1:Sl4aGygMT6LrqrWclx+PTx3U+LnKx/seiNR+3G19Ar8=
+golang.org/x/tools v0.0.0-20200331202046-9d5940d49312 h1:2PHG+Ia3gK1K2kjxZnSylizb//eyaMG8gDFbOG7wLV8=
+golang.org/x/tools v0.0.0-20200331202046-9d5940d49312/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=

pkg/apis/zookeeper/v1beta1/zookeepercluster_types.go

@@ -12,6 +12,7 @@ package v1beta1
 
 import (
 	"fmt"
+	"strings"
 
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
@@ -59,13 +60,19 @@ type ZookeeperClusterSpec struct {
 	Ports []v1.ContainerPort `json:"ports,omitempty"`
 
 	// Pod defines the policy to create pod for the zookeeper cluster.
-	//
 	// Updating the Pod does not take effect on any existing pods.
 	Pod PodPolicy `json:"pod,omitempty"`
 
+	//StorageType is used to tell which type of storage we will be using
+	//It can take either Ephemeral or persistence
+	//Default StorageType is Persistence storage
+	StorageType string `json:"storageType,omitempty"`
 	// Persistence is the configuration for zookeeper persistent layer.
 	// PersistentVolumeClaimSpec and VolumeReclaimPolicy can be specified in here.
 	Persistence *Persistence `json:"persistence,omitempty"`
+	// Ephemeral is the configuration which helps create ephemeral storage
+	// At anypoint only one of Persistence or Ephemeral should be present in the manifest
+	Ephemeral *Ephemeral `json:"ephemeral,omitempty"`
 
 	// Conf is the zookeeper configuration, which will be used to generate the
 	// static zookeeper configuration. If no configuration is provided required
@@ -160,18 +167,27 @@ func (s *ZookeeperClusterSpec) withDefaults(z *ZookeeperCluster) (changed bool)
 	if s.Pod.withDefaults(z) {
 		changed = true
 	}
-	if s.Persistence == nil {
-		s.Persistence = &Persistence{}
-		changed = true
-	}
-	if s.Persistence.withDefaults() {
-		changed = true
+	if strings.EqualFold(s.StorageType, "ephemeral") {
+		if s.Ephemeral == nil {
+			s.Ephemeral = &Ephemeral{}
+			s.Ephemeral.EmptyDirVolumeSource = v1.EmptyDirVolumeSource{}
+			changed = true
+		}
+	} else {
+		if s.Persistence == nil {
+			s.StorageType = "persistence"
+			s.Persistence = &Persistence{}
+			changed = true
+		}
+		if s.Persistence.withDefaults() {
+			s.StorageType = "persistence"
+			changed = true
+		}
 	}
 	return changed
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
-
 // ZookeeperCluster is the Schema for the zookeeperclusters API
 // +k8s:openapi-gen=true
 type ZookeeperCluster struct {
@@ -400,17 +416,24 @@ type Persistence struct {
 	// The default value is Retain.
 	VolumeReclaimPolicy VolumeReclaimPolicy `json:"reclaimPolicy,omitempty"`
 	// PersistentVolumeClaimSpec is the spec to describe PVC for the container
-	// This field is optional. If no PVC spec, stateful containers will use
-	// emptyDir as volume.
+	// This field is optional. If no PVC is specified default persistentvolume
+	// will get created.
 	PersistentVolumeClaimSpec v1.PersistentVolumeClaimSpec `json:"spec,omitempty"`
 }
 
+type Ephemeral struct {
+	//EmptyDirVolumeSource is optional and this will create the emptydir volume
+	//It has two parameters Medium and SizeLimit which are optional as well
+	//Medium specifies What type of storage medium should back this directory.
+	//SizeLimit specifies Total amount of local storage required for this EmptyDir volume.
+	EmptyDirVolumeSource v1.EmptyDirVolumeSource `json:"emptydirvolumesource,omitempty"`
+}
+
 func (p *Persistence) withDefaults() (changed bool) {
 	if !p.VolumeReclaimPolicy.isValid() {
 		changed = true
 		p.VolumeReclaimPolicy = VolumeReclaimPolicyRetain
 	}
-
 	p.PersistentVolumeClaimSpec.AccessModes = []v1.PersistentVolumeAccessMode{
 		v1.ReadWriteOnce,
 	}

pkg/apis/zookeeper/v1beta1/zookeepercluster_types_test.go

@@ -99,6 +99,19 @@ var _ = Describe("ZookeeperCluster Types", func() {
 			})
 		})
 
+		Context(" Ephemeral Storage", func() {
+			var z1 v1beta1.ZookeeperCluster
+			BeforeEach(func() {
+				z1 = *z.DeepCopy()
+				z1.Spec.StorageType = "ephemeral"
+				z1.WithDefaults()
+			})
+
+			It("should set the ephemeralstorage and value for EmptyDirVolumeSource.Medium to ''", func() {
+				Ω(fmt.Sprintf("%s", z1.Spec.Ephemeral.EmptyDirVolumeSource.Medium)).To(Equal(""))
+			})
+		})
+
 		Context("Conf", func() {
 			var c v1beta1.ZookeeperConfig
 

pkg/controller/zookeepercluster/zookeepercluster_controller.go

@@ -610,7 +610,7 @@ func (r *ReconcileZookeeperCluster) yamlConfigMap(instance *zookeeperv1beta1.Zoo
 }
 
 func (r *ReconcileZookeeperCluster) reconcileFinalizers(instance *zookeeperv1beta1.ZookeeperCluster) (err error) {
-	if instance.Spec.Persistence.VolumeReclaimPolicy != zookeeperv1beta1.VolumeReclaimPolicyDelete {
+	if instance.Spec.Persistence != nil && instance.Spec.Persistence.VolumeReclaimPolicy != zookeeperv1beta1.VolumeReclaimPolicyDelete {
 		return nil
 	}
 	if instance.DeletionTimestamp.IsZero() {

pkg/test/e2e/e2eutil/spec_util.go

@@ -40,3 +40,11 @@ func NewClusterWithVersion(namespace, version string) *api.ZookeeperCluster {
 	}
 	return cluster
 }
+
+func NewClusterWithEmptyDir(namespace string) *api.ZookeeperCluster {
+	cluster := NewDefaultCluster(namespace)
+	cluster.Spec = api.ZookeeperClusterSpec{
+		StorageType: "ephemeral",
+	}
+	return cluster
+}