fix: cleanup MinIOInstance Controller (#85)

- Update k8s.io/client-go version to v0.18.2
- Add MirrorInstance Controller

README.md

@@ -12,7 +12,7 @@ MinIO is a high performance distributed object storage server, designed for larg
 
 ### Prerequisites
 
-- Kubernetes version v1.15.5 and above.
+- Kubernetes version v1.17.0 and above for compatibility. MinIO Operator uses `k8s/client-go` v0.18.0.
 - `kubectl` configured to refer to a Kubernetes cluster.
 
 ### Create Operator and related resources
@@ -26,7 +26,7 @@ kubectl create -f https://raw.githubusercontent.com/minio/minio-operator/master/
 This will create all relevant resources required for the Operator to work. Here is a list of resources created by above `yaml` file:
 
 - `Namespace`: Custom namespace for MinIO-Operator. By default it is named as `minio-operator-ns`.
-- `CustomResourceDefinition`: Custom resource definition named as `minioinstances.miniocontroller.min.io`.
+- `CustomResourceDefinition`: Custom resource definition named as `minioinstances.miniooperator.min.io`.
 - `ClusterRole`: A cluster wide role for the controller. It is named as `minio-operator-role`. This is used for RBAC.
 - `ServiceAccount`: Service account is used by the custom controller to access the cluster. Account name by default is `minio-operator-sa`.
 - `ClusterRoleBinding`: This cluster wide binding binds the service account `minio-operator-sa` to cluster role `minio-operator-role`.
@@ -36,10 +36,10 @@ This will create all relevant resources required for the Operator to work. Here
 
 These variables may be passed to operator Deployment in order to modify some of its parameters
 
-| name                | default | description                                                                                                                   |
+| Name                | Default | Description                                                                                                                   |
 | ---                 | ---     | ---                                                                                                                           |
 | `WATCHED_NAMESPACE` |         | If set, the operator will watch only MinIO resources deployed in the specified namespace. All namespaces are watched if empty |
-| `CLUSTER_DOMAIN` | cluster.local | "cluster domain" of the kubernetes cluster the operator is to be installed on |
+| `CLUSTER_DOMAIN`    | cluster.local | Cluster Domain of the Kubernetes cluster |
 
 ### Create a MinIO instance
 
@@ -51,13 +51,21 @@ kubectl create -f https://raw.githubusercontent.com/minio/minio-operator/master/
 
 ### Expand a MinIO cluster
 
-After you have a distributed MinIO Cluster running (zones.server > 3), you can expand the MinIO cluster using
+After you have a distributed MinIO Cluster running (zones.server >= 4), you can expand the MinIO cluster using
 
 ```
-kubectl patch minioinstances.miniocontroller.min.io minio --patch "$(cat examples/patch.yaml)" --type=merge
+kubectl patch minioinstances.miniooperator.min.io minio --patch "$(cat examples/patch.yaml)" --type=merge
 ```
 
-You can further keep adding new zones in the `patch.yaml` file and apply the patch, to add new nodes to existing cluster. 
+You can expand an existing cluster by adding new zones to the `patch.yaml` and run the above `kubectl-patch` command.
+
+**NOTE**: Important point to consider _before_ using cluster expansion:
+
+During cluster expansion, MinIO Operator removes the existing StatefulSet and creates a new StatefulSet with required number of Pods. This means, there is a short downtime during expansion, as the pods are terminated and created again.
+
+As existing StatefulSet pods are terminated, its PVCs are also deleted. It is _very important_ to ensure PVs bound to MinIO StatefulSet PVCs are not deleted at this time to avoid data loss. We recommend configuring every PV with reclaim policy [`retain`](https://kubernetes.io/docs/concepts/storage/persistent-volumes/#retain), to ensure the PV is not deleted.
+
+If you attempt cluster expansion while the PV reclaim policy is set to something else, it may lead to data loss. If you have the reclaim policy set to something else, change it as explained in [Kubernetes documents](https://kubernetes.io/docs/tasks/administer-cluster/change-pv-reclaim-policy/).
 
 ## Features
 
@@ -71,8 +79,6 @@ Refer [`minioinstance.yaml`](https://raw.githubusercontent.com/minio/minio-opera
 
 ## Upcoming features
 
-- Bucket Expansion Support
-- Federation and CoreDNS
 - Continuous remote site mirroring with [`mc mirror`](https://docs.minio.io/docs/minio-client-complete-guide.html#mirror)
 
 ## Explore Further

examples/minioinstance.yaml

@@ -7,7 +7,20 @@ data:
   accesskey: bWluaW8= # base 64 encoded "minio" (echo -n 'minio' | base64)
   secretkey: bWluaW8xMjM= # based 64 encoded "minio123" (echo -n 'minio123' | base64)
 ---
-apiVersion: miniocontroller.min.io/v1beta1
+apiVersion: v1
+kind: Service
+metadata:
+  name: minio-service
+spec:
+  type: ClusterIP
+  ports:
+    - port: 9000
+      targetPort: 9000
+      protocol: TCP
+  selector:
+    app: minio
+---
+apiVersion: miniooperator.min.io/v1beta1
 kind: MinIOInstance
 metadata:
   name: minio
@@ -28,7 +41,7 @@ spec:
       prometheus.io/port: "9000"
       prometheus.io/scrape: "true"
   ## Registry location and Tag to download MinIO Server image
-  image: minio/minio:RELEASE.2020-04-15T00-39-01Z
+  image: minio/minio:RELEASE.2020-04-23T00-58-49Z
   zones:
     - name: "zone-0"
       ## Number of MinIO servers/pods in this zone.
@@ -101,7 +114,7 @@ spec:
       path: /minio/health/live
       port: 9000
     initialDelaySeconds: 120
-    periodSeconds: 20
+    periodSeconds: 60
   ## Readiness probe detects situations when MinIO server instance
   ## is not ready to accept traffic. Kubernetes doesn't forward
   ## traffic to the pod while readiness checks fail.
@@ -112,7 +125,7 @@ spec:
       path: /minio/health/ready
       port: 9000
     initialDelaySeconds: 120
-    periodSeconds: 20
+    periodSeconds: 60
   ## nodeSelector parameters for MinIO Pods. It specifies a map of key-value pairs. For the pod to be
   ## eligible to run on a node, the node must have each of the
   ## indicated key-value pairs as labels.
@@ -122,4 +135,3 @@ spec:
   ## Affinity settings for MinIO pods. Read more about affinity
   ## here: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity.
   # affinity:
-

examples/patch.yaml

@@ -1,11 +1,7 @@
-apiVersion: miniocontroller.min.io/v1beta1
+apiVersion: miniooperator.min.io/v1beta1
 kind: MinIOInstance
 metadata:
   name: minio
-## If specified, MinIOInstance pods will be dispatched by specified scheduler.
-## If not specified, the pod will be dispatched by default scheduler.
-# scheduler:
-#  name: my-custom-scheduler
 spec:
   zones:
     - name: "zone-0"

go.mod

@@ -3,33 +3,15 @@ module github.com/minio/minio-operator
 go 1.13
 
 require (
-	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/evanphx/json-patch v4.5.0+incompatible // indirect
-	github.com/ghodss/yaml v0.0.0-20180820084758-c7ce16629ff4 // indirect
-	github.com/gogo/protobuf v0.0.0-20170702163824-dda3e8acadcc // indirect
 	github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b
 	github.com/golang/groupcache v0.0.0-20180924190550-6f2cf27854a4 // indirect
-	github.com/google/btree v1.0.0 // indirect
-	github.com/google/gofuzz v0.0.0-20170612174753-24818f796faf // indirect
-	github.com/googleapis/gnostic v0.0.0-20180520015035-48a0ecefe2e4 // indirect
-	github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7 // indirect
-	github.com/hashicorp/golang-lru v0.5.0 // indirect
+	github.com/golang/protobuf v1.3.3 // indirect
 	github.com/imdario/mergo v0.3.6 // indirect
-	github.com/json-iterator/go v1.1.5 // indirect
-	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
-	github.com/modern-go/reflect2 v1.0.1 // indirect
-	github.com/onsi/ginkgo v1.10.1 // indirect
-	github.com/onsi/gomega v1.7.0 // indirect
-	github.com/peterbourgon/diskv v0.0.0-20180312054125-0646ccaebea1 // indirect
 	github.com/pkg/errors v0.8.1 // indirect
-	github.com/spf13/pflag v1.0.3 // indirect
-	github.com/stretchr/testify v1.3.0
-	golang.org/x/crypto v0.0.0-20180808211826-de0752318171 // indirect
-	golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45 // indirect
-	golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2 // indirect
-	gopkg.in/inf.v0 v0.9.1 // indirect
-	k8s.io/api v0.0.0-20181014053814-bbf5c193d86c
-	k8s.io/apimachinery v0.0.0-20181015213631-60666be32c5d
-	k8s.io/client-go v0.0.0-20181016014101-70926af6e803
-	k8s.io/kube-openapi v0.0.0-20180719232738-d8ea2fe547a4 // indirect
+	github.com/stretchr/testify v1.4.0
+	k8s.io/api v0.18.0
+	k8s.io/apimachinery v0.18.0
+	k8s.io/client-go v0.18.0
+	k8s.io/kube-openapi v0.0.0-20200316234421-82d701f24f9d // indirect
 )