docs: add a solution demo for StackGres

solutions/stackgres/README.md

@@ -0,0 +1,248 @@
+# Solutions for StackGres
+Here is a demo for building a sharded PostgreSQL cluster with Apache ShardingSphere and StackGres. The basic architecture could be described as :
+
+```shell
+
++--------------------------+        +-----------------------------+
+| ShardingSphere Operator  | -----> | Apache ShardingSphere Proxy | 
++--------------------------+        +-----------------------------+
+                                                   |
+						   V
+				    +-----------------------------+
++--------------------------+        |    SGCluster Cluster-1      | 
+|   StackGres Operator     | -----> +-----------------------------+
++--------------------------+        |    SGCluster Cluster-2      | 
+                                    +-----------------------------+
+```
+
+
+## Demo
+
+1. Create a Kubernetes namespace for demo
+
+```shell
+kubectl create namespace sg-demo
+```
+
+2. Install StackGres with Helm Charts 
+
+```shell
+# Add StachGres Helm repo
+helm repo add stackgres-charts https://stackgres.io/downloads/stackgres-k8s/stackgres/helm/
+
+# Install StachGres operator
+helm install --namespace sg-demo stackgres-operator stackgres-charts/stackgres-operator
+```
+
+![](./static/stackgres-operator.png)
+![](./static/stackgres-operator-installation.png)
+![](./static/check-stackgres-operator.png)
+
+3. Create two minimum SGCluster
+
+```shell
+cat << 'EOF' | kubectl create -f -
+apiVersion: stackgres.io/v1
+kind: SGCluster
+metadata:
+  name: cluster-1
+  namespace: sg-demo
+spec:
+  instances: 1
+  postgres:
+    version: 'latest'
+  pods:
+    persistentVolume: 
+      size: '5Gi'
+EOF
+
+cat << 'EOF' | kubectl create -f -
+apiVersion: stackgres.io/v1
+kind: SGCluster
+metadata:
+  name: cluster-2
+  namespace: sg-demo
+spec:
+  instances: 1
+  postgres:
+    version: 'latest'
+  pods:
+    persistentVolume: 
+      size: '5Gi'
+EOF
+```
+<img src="./static/create-sgcluster.png" width="500" height="650" />
+
+![](./static/check-sgclusters.png)
+
+4. Retrieve two SGCluster PostgreSQL username and password by decoding the secrets
+
+```shell
+# Retrieve username and password of cluster-1, which is postgres / 5bc0-07f8-40b3-b81
+kubectl get secret cluster-1 -n sg-demo -o jsonpath="{.data.superuser-username}" | base64 -d
+kubectl get secret cluster-1 -n sg-demo -o jsonpath="{.data.superuser-password}" | base64 -d
+
+# Retrieve username and password of cluster-2, which is postgres / 700e-33b3-4edf-bde
+kubectl get secret cluster-2 -n sg-demo -o jsonpath="{.data.superuser-username}" | base64 -d
+kubectl get secret cluster-2 -n sg-demo -o jsonpath="{.data.superuser-password}" | base64 -d
+```
+
+5. Install the ShardingSphere Operator 
+
+```
+# Add Apache ShardingSphere Helm repo
+helm repo add shardingsphere https://apache.github.io/shardingsphere-on-cloud
+
+# Install ShardingSphere operator 
+helm install shardingsphere-operator shardingsphere/apache-shardingsphere-operator-charts -n sg-demo --set zookeeper.persistence.enabled=false --set operator.featureGates.computeNode=true --set proxyCluster.enabled=false
+```
+![](./static/shardingsphere-operator-helm.png)
+![](./static/shardingsphere-operator-installation.png)
+![](./static/shardingsphere-operator-installation-2.png)
+![](./static/check-shardingsphere-operator.png)
+
+6. Create a ComputeNode
+
+```shell
+cat << EOF | kubectl create -f -
+apiVersion: shardingsphere.apache.org/v1alpha1
+kind: ComputeNode
+metadata:
+  annotations:
+    shardingsphere.apache.org/java-agent-enabled: "true"
+    prometheus.io/path: "/metrics"
+    prometheus.io/scrape: "true"
+    prometheus.io/port: "9090"
+  labels:
+    app: shardingsphere-proxy
+  name: shardingsphere-proxy
+  namespace: sg-demo
+spec:
+  serverVersion: 5.4.1
+  replicas: 1
+  selector:
+    matchLabels:
+      app: shardingsphere-proxy
+  portBindings:
+  - name: server
+    containerPort: 5432
+    servicePort: 5432
+    protocol: TCP
+  serviceType: ClusterIP
+  bootstrap:
+    serverConfig:
+      authority:
+        privilege:
+          type: ALL_PERMITTED
+        users:
+        - user: root@%
+          password: root
+      mode:
+        type: Cluster
+        repository:
+          type: ZooKeeper
+          props:
+            timeToLiveSeconds: "600"
+            server-lists: shardingsphere-operator-zookeeper.sg-demo:2181
+            retryIntervalMilliseconds: "500"
+            operationTimeoutMilliseconds: "5000"
+            namespace: governance_ds
+            maxRetries: "3"
+      props:
+        proxy-frontend-database-protocol-type: PostgreSQL
+        proxy-default-port: "5432"
+    agentConfig:
+      plugins:
+        logging:
+          file:
+            props:
+              level: "INFO"
+        metrics:
+          prometheus:
+            host: "0.0.0.0"
+            port: 9090
+            props:
+              jvm-information-collector-enabled: "true"
+EOF
+```
+![](./static/computenode.png)
+
+7. Connect to ShardingSphere Proxy and register a cluster   
+
+```shell
+# Using kubectl port-forward to expose ShardingSphere Proxy for localhost connection
+ kubectl port-forward svc/shardingsphere-proxy  -n sg-demo 5432:5432
+
+# Using psql to connect to ShardingSphere Proxy
+psql -h 127.0.0.1 -p 5432 postgres root
+
+# Create a logical database named sharding_db;
+postgres=> CREATE DATABASE sharding_db;
+
+# Change to this database
+postgres=> \c sharding_db;
+
+# Register storage units
+sharding_db=> REGISTER STORAGE UNIT ds_0 (HOST="cluster-1.sg-demo", PORT=5432, DB="postgres", USER="postgres", PASSWORD="5bc0-07f8-40b3-b81"),ds_1(HOST="cluster-2.sg-demo", PORT=5432, DB="postgres", USER="postgres", PASSWORD="700e-33b3-4edf-bde");
+
+# Create sharding table rule 
+sharding_db=> CREATE SHARDING TABLE RULE t_order(STORAGE_UNITS(ds_0,ds_1),SHARDING_COLUMN=order_id,TYPE(NAME="hash_mod",PROPERTIES("sharding-count"="2")),KEY_GENERATE_STRATEGY(COLUMN=order_id,TYPE(NAME="snowflake"))); 
+
+# Create logical table
+sharding_db=> CREATE TABLE t_order (
+   order_id INT PRIMARY KEY  NOT NULL,
+   user_id  INT    NOT NULL,
+   status        CHAR(50)
+);
+```
+![](./static/shardingsphere-operation-1.png)
+![](./static/shardingsphere-create-database.png)
+![](./static/shardingsphere-change-db.png)
+![](./static/shardingsphere-register-storage-units.png)
+![](./static/shardingsphere-create-sharding-table-rule.png)
+
+8. Insert test data
+```shell
+# Insert
+sharding_db=> INSERT INTO t_order(order_id, user_id, status) VALUES(1, 1, 'code1'),(2, 2, 'code2'),(3, 3, 'code3'),(4, 4, 'code4');
+
+# Select 
+sharding_db=> SELECT * FROM t_order;
+```
+
+![](./static/insert-data.png)
+![](./static/select-data-from-shardingsphere.png)
+
+9. Query data with every SGCluster 
+```shell
+# Access SGCluster via psql
+kubectl exec -ti cluster-1-0 -n sg-demo  -c postgres-util -- psql
+
+# Query tables 
+\d
+
+# Query data from cluster-1
+SELECT * FROM t_order_0;
+```
+
+![](./static/select-data-from-cluster-1.png)
+
+```shell
+# Access SGCluster via psql
+kubectl exec -ti cluster-2-0 -n sg-demo  -c postgres-util -- psql
+
+# Query tables 
+\d
+
+# Query data from cluster-2
+SELECT * FROM t_order_1;
+```
+![](./static/select-data-from-cluster-2.png)
+
+## References
+* [https://stackgres.io/doc/latest/quickstart/](https://stackgres.io/doc/latest/quickstart/)
+* [https://stackgres.io/doc/latest/install/helm/](https://stackgres.io/doc/latest/install/helm/)
+* [https://stackgres.io/doc/latest/administration/cluster/connection/passwords/](https://stackgres.io/doc/latest/administration/cluster/connection/passwords/)
+* [https://stackgres.io/doc/latest/administration/cluster/connection/dns/](https://stackgres.io/doc/latest/administration/cluster/connection/dns/)
+* [https://shardingsphere.apache.org/oncloud/current/en/user-manual/cn-sn-operator/](https://shardingsphere.apache.org/oncloud/current/en/user-manual/cn-sn-operator/)
+* [https://shardingsphere.apache.org/document/current/en/user-manual/shardingsphere-proxy/distsql/usage/sharding-rule/](https://shardingsphere.apache.org/document/current/en/user-manual/shardingsphere-proxy/distsql/usage/sharding-rule/)