https://github.com/j3k0/tica42s-auto-scaler

A *very* simple auto-scaler for Telegraf + InfluxDB + Cloudflare + AWS EC2, for 2 servers
https://github.com/j3k0/tica42s-auto-scaler

Last synced: 22 days ago
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A *very* simple auto-scaler for Telegraf + InfluxDB + Cloudflare + AWS EC2, for 2 servers

• Host: GitHub
• URL: https://github.com/j3k0/tica42s-auto-scaler
• Owner: j3k0
• Created: 2020-03-12T08:37:27.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2021-11-16T22:13:32.000Z (almost 3 years ago)
• Last Synced: 2024-04-08T00:24:14.745Z (7 months ago)
• Language: JavaScript
• Homepage:
• Size: 20.5 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
# simple-influx-ec2-auto-scaler

> A *very* simple auto-scaler for EC2 + InfluxDB + Telegraf

### What does it do?

Auto-scale is a big word: this is for a 2 servers setup:

- 1 _master_ server

- 1 _backup_ server.

The master server is automatically selected, as the first ec2 InstanceId in alphabetical order.

In our setup, all servers are identical and behind a load balancer from cloudflare. Requests will be balanced equally between running servers.

This script will:

- Check current load on the master server

- Start backup server if:

  - master server is not reporting (it might be down)

  - master server load is over a given threshold

- Stop backup server otherwise.

- Update cloudflare loadbalancer pool's origins.

### How does it work?

A NodeJS script will run every 5 minutes (by default).

The load of the server is retrieved from InfluxDB, as gathered by Telegraf's [System Input Plugin](https://github.com/influxdata/telegraf/tree/master/plugins/inputs/system).

AWS SDK is used to update the state of the backup server.

## Getting started

You can run from docker.

1. `cp docker-compose.example.yml docker-compose.yml`

2. Edit docker-compose.yml (see `Configuration` below)

3. Run with `docker-compose up`

Or using NodeJS:

1. Install dependencies: `npm install`

2. Set your environment variables (see `Configuration` below)

3. Start `node index.js`

#### Configuration

The execution is controlled by environment variables.

- `INFLUX_HOST` - Address of the influxdb instance

- `INFLUX_DATABASE` - Name of the telegraf database (default: telegraf)

- `RUN_INTERVAL_MS` - Interval in milliseconds between runs (default: 300000)

- `LOAD_THRESHOLD` - Threshold that triggers starting the backup (default: 0.2)

- `AWS_ACCESS_KEY_ID` - AWS access key

- `AWS_SECRET_ACCESS_KEY` - AWS secret access key

- `AWS_REGION` - AWS region where the backup server is running

- `EC2_TAG_KEY` - EC2 hosts have the following tag (default: Name)

- `EC2_TAG_VALUE` - Expected value for the tag filter

- `TELEGRAF_HOST_PREFIX` - Prefix appended to telegraf hostnames

  - hostnames are expected to be ``

- `CLOUDFLARE_AUTH_EMAIL` - Cloudflare API authentication email

- `CLOUDFLARE_AUTH_KEY` - Cloudflare API authentication key

- `CLOUDFLARE_ACCOUNT_ID` - Your account ID

  - Retrieve with `curl -H "X-Auth-Key: $CLOUDFLARE_AUTH_KEY" -H "X-Auth-Email: $CLOUDFLARE_AUTH_EMAIL" https://api.cloudflare.com/client/v4/accounts`

- `CLOUDFLARE_POOL_ID` - The pool ID to update

  - Retrieve with `curl -H "X-Auth-Key: $CLOUDFLARE_AUTH_KEY" -H "X-Auth-Email: $CLOUDFLARE_AUTH_EMAIL" "https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/load_balancers/pools"`