Add tablets demo with UI

Author: zseta

README.md

@@ -1,9 +1,12 @@
 # ScyllaDB 1 million operations/second DEMOs
 
-This repository contains Terraform configuration files for setting up a 1 million operations/second DEMO with different flavours of ScyllaDB:
+Set up 1 million operations/second DEMO with different flavours of ScyllaDB:
 * [1 million operations/second with ScyllaDB Cloud](/scylladb-cloud)
 * [1 million operations/second with ScyllaDB Enterprise](/scylladb-enterprise)
 
+Scale a cluster from 3 to 6 nodes with Tablets enabled:
+* [ScyllaDB Tablets DEMO on AWS](/tablets-scaling)
+
 ## Usage
 1. Clone the repository
     ```

tablets-scaling/README.md

@@ -0,0 +1,50 @@
+# ScyllaDB Tablets DEMO
+This project walks you through the following scenario:
+1. Starting off with 3 ScyllaDB nodes
+1. Spike in the number of requests
+1. Add 3 additional ScyllaDB nodes to handle requests
+1. Request volume goes down
+1. Remove 3 nodes
+
+## Requirements
+* AWS account
+* [Terraform](https://developer.hashicorp.com/terraform/tutorials/aws-get-started/install-cli)
+* [Ansible](https://docs.ansible.com/ansible/latest/installation_guide/intro_installation.html)
+* Python
+
+## Usage
+1. Clone the repository
+    ```
+    git clone https://github.com/scylladb/1m-ops-demo.git
+    cd 1m-ops-demo/tablets/scaling
+    ```
+1. Set your variables in `variables.tf`
+1. Set up EC2 instances on AWS (takes 4+ minutes)
+    ```bash
+    terraform init
+    terraform plan
+    terraform apply
+    ```
+1. Start Python server
+    
+    Install requirements in a new environment, and start the server:
+    ```
+    virtualenv env
+    source env/bin/activate
+    pip install -r requirements.txt
+    python app.py
+    ```
+
+    Output:
+    ```
+    * Serving Flask app 'app'
+    * Debug mode: off
+    WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
+    * Running on all addresses (0.0.0.0)
+    * Running on http://127.0.0.1:5000
+    * Running on http://192.168.0.47:5000
+    ```
+1. Open the DEMO UI
+    ```
+    http://127.0.0.1:5000
+    ```

tablets-scaling/ansible/1_original_cluster.yml

@@ -0,0 +1,20 @@
+---
+- name: Start cluster
+  hosts: original_cluster
+  become: True
+
+  tasks: 
+    - name: Start ScyllaDB Service
+      ansible.builtin.systemd_service:
+        name: scylla-server.service
+        state: started
+
+    - name: Waiting for CQL port readiness
+      wait_for:
+        port: 9042
+        host: 127.0.0.1
+        connect_timeout: 3
+        delay: 3
+        sleep: 10
+        timeout: 1200
+        state: present

tablets-scaling/ansible/2_restore_snapshot.yml

@@ -0,0 +1,12 @@
+---
+- name: Restore snapshot
+  hosts: original_cluster[0]
+  become: True
+  tasks:
+    - name: Create schema
+      ansible.builtin.shell: 'cqlsh -f /home/ubuntu/schema.cql'
+    - name: Restore snapshot 
+      ansible.builtin.shell: bash /home/ubuntu/restore_snapshot.sh
+    - name: Nodetool refresh
+      ansible.builtin.shell: 'nodetool refresh keyspace1 standard1'
+

tablets-scaling/ansible/3_stress.yml

@@ -0,0 +1,12 @@
+---
+- name: Start loader
+  hosts: stress
+  become: True
+
+  tasks: 
+    - name: Start CQL Stress
+      ansible.builtin.systemd_service:
+        name: cql-stress.service
+        state: started
+        daemon_reload: True
+

tablets-scaling/ansible/4_scale_out.yml

@@ -0,0 +1,21 @@
+---
+- name: Scale out
+  hosts: scale_out
+  become: True
+
+  tasks: 
+    - name: Start ScyllaDB Service
+      ansible.builtin.systemd_service:
+        name: scylla-server.service
+        state: started
+
+    - name: Waiting for CQL port readiness
+      wait_for:
+        port: 9042
+        host: 127.0.0.1
+        connect_timeout: 3
+        delay: 3
+        sleep: 10
+        timeout: 1200
+        state: present
+

tablets-scaling/ansible/5_stop_stress.yml

@@ -0,0 +1,10 @@
+---
+- name: Stop loader
+  hosts: stress
+  become: True
+
+  tasks: 
+    - name: Stop CQL Stress
+      ansible.builtin.systemd_service:
+        name: cql-stress.service
+        state: stopped

tablets-scaling/ansible/6_scale_in.yml

@@ -0,0 +1,19 @@
+---
+- name: Scale in
+  hosts: scale_out
+  become: True
+
+  tasks: 
+    - name: Decommission node
+      ansible.builtin.shell:
+        cmd: nodetool decommission
+
+    - name: Stop ScyllaDB
+      ansible.builtin.systemd_service:
+        name: scylla-server.service
+        state: stopped
+
+    - name: Wipe data-dir
+      ansible.builtin.shell:
+        cmd: 'rm -fr /var/lib/scylla/data/* ;  find /var/lib/scylla -type f -delete'
+

tablets-scaling/ansible/restore_snapshot.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+sudo apt-get install unzip
+cd /var/lib/scylla/data/keyspace1/standard1-*/upload
+wget https://scylla-devrel.s3.us-east-2.amazonaws.com/tablets-sample-data/scylla.zip
+unzip scylla.zip
+rm scylla.zip
+sudo chown -R scylla:scylla *

tablets-scaling/app.py

@@ -0,0 +1,95 @@
+from flask import Flask, render_template_string
+from flask_socketio import SocketIO
+import os
+import subprocess
+import configparser
+
+app = Flask(__name__)
+socketio = SocketIO(app)
+
+env = os.environ.copy()
+env["PYTHONUNBUFFERED"] = "1"
+env["ANSIBLE_FORCE_COLOR"] = "1"
+
+def read_file_to_string(file_path):
+    """
+    Reads the file and returns it as a string.
+    
+    :param file_path: Path to the file
+    :return: The contents of the file as a string
+    """
+    try:
+        with open(file_path, 'r') as file:
+            content = file.read()
+        return content
+    except FileNotFoundError:
+        print(f"Error: File not found at {file_path}")
+        return ""
+    except Exception as e:
+        print(f"An error occurred: {e}")
+        return ""
+
+@app.route("/")
+def index():
+    return render_template_string(read_file_to_string("index.html"))
+
+# Global process variable
+globals()["process"] = None
+
+def run_ansible_playbook(playbook_path):
+    playbook_cmd = ["ansible-playbook", playbook_path]
+    process = subprocess.Popen(playbook_cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True, cwd=ansible_folder)
+    for line in process.stdout:
+        socketio.emit("playbook_output", {"output": line})
+        socketio.sleep(0)
+    process.wait()
+
+@socketio.on("original_cluster")
+def handle_original_cluster():
+    run_ansible_playbook(ansible_folder + "/1_original_cluster.yml")
+    
+@socketio.on("sample_data")
+def handle_sample_data():
+    run_ansible_playbook(ansible_folder + "/2_restore_snapshot.yml")
+
+@socketio.on("start_stress")
+def handle_start_stress():
+    run_ansible_playbook(ansible_folder + "/3_stress.yml")
+
+@socketio.on("scale_out")
+def handle_scale_out():
+    run_ansible_playbook(ansible_folder + "/4_scale_out.yml")
+
+@socketio.on("stop_stress")
+def handle_stop_stress():
+    run_ansible_playbook(ansible_folder + "/5_stop_stress.yml")
+
+@socketio.on("scale_in")
+def handle_scale_in():
+    run_ansible_playbook(ansible_folder + "/6_scale_in.yml")
+
+
+def parse_ansible_inventory(inventory_file):
+    config = configparser.ConfigParser(allow_no_value=True)
+    config.optionxform = str  # Preserve case sensitivity
+    
+    # Read the inventory file
+    config.read(inventory_file)
+
+    inventory = {}
+    for section in config.sections():
+        hosts = {}
+        for item in config.items(section):
+            hostname, *variables = item[0].split()
+            host_vars = dict(var.split('=') for var in variables)
+            hosts[hostname] = host_vars
+        inventory[section] = hosts
+
+    return inventory
+
+if __name__ == "__main__":
+    program_cwd = os.path.dirname(os.path.abspath(__file__))
+    ansible_folder = os.path.join(program_cwd, "ansible")
+
+    socketio.run(app, host='0.0.0.0', port=5000, allow_unsafe_werkzeug=True)
+

tablets-scaling/data.tf

@@ -0,0 +1,20 @@
+data "aws_availability_zones" "azs" {}
+
+data "aws_caller_identity" "current" {}
+
+data "aws_region" "current" {}
+
+data "aws_instances" "scylladb" {
+  filter {
+    name   = "tag:Project"
+    values = [var.custom_name]
+  }
+
+  filter {
+    name   = "tag:Type"
+    values = ["Scylla"]
+  }
+}
+data "aws_vpc" "selected" {
+  id = aws_vpc.custom_vpc.id
+}