Deployment of demo.pyspider.org
===============================

[demo.pyspider.org](http://demo.pyspider.org/) is running on three VPSs connected together with private network using [tinc](http://www.tinc-vpn.org/).

1vCore 4GB RAM | 1vCore 2GB RAM * 2
---------------|----------------
database<br>message queue<br>scheduler | phantomjs * 2<br>phantomjs-lb * 1<br>fetcher * 1<br>fetcher-lb * 1<br>processor * 2<br>result-worker * 1<br>webui * 4<br>webui-lb * 1<br>nginx * 1<br>

All components are running inside docker containers.

database / message queue / scheduler
------------------------------------

The database is postgresql and the message queue is redis.

Scheduler may have a lot of database operations, it's better to put it close to the database.

```bash
docker run --name postgres -v /data/postgres/:/var/lib/postgresql/data -d -p $LOCAL_IP:5432:5432 -e POSTGRES_PASSWORD="" postgres
docker run --name redis -d -p  $LOCAL_IP:6379:6379 redis
docker run --name scheduler -d -p $LOCAL_IP:23333:23333 --restart=always binux/pyspider \
 --taskdb "sqlalchemy+postgresql+taskdb://binux@10.21.0.7/taskdb" \
 --resultdb "sqlalchemy+postgresql+resultdb://binux@10.21.0.7/resultdb" \
 --projectdb "sqlalchemy+postgresql+projectdb://binux@10.21.0.7/projectdb" \
 --message-queue "redis://10.21.0.7:6379/1" \
 scheduler --inqueue-limit 5000 --delete-time 43200
```

other components
----------------

fetcher, processor, result_worker are running on two boxes with same configuration managed with [docker-compose](https://docs.docker.com/compose/).

```yaml
phantomjs:
  image: 'binux/pyspider:latest'
  command: phantomjs
  cpu_shares: 512
  environment:
    - 'EXCLUDE_PORTS=5000,23333,24444'
  expose:
    - '25555'
  mem_limit: 512m
  restart: always
phantomjs-lb:
  image: 'dockercloud/haproxy:latest'
  links:
    - phantomjs
  restart: always
  
fetcher:
  image: 'binux/pyspider:latest'
  command: '--message-queue "redis://10.21.0.7:6379/1" --phantomjs-proxy "phantomjs:80" fetcher --xmlrpc'
  cpu_shares: 512
  environment:
    - 'EXCLUDE_PORTS=5000,25555,23333'
  links:
    - 'phantomjs-lb:phantomjs'
  mem_limit: 128m
  restart: always
fetcher-lb:
  image: 'dockercloud/haproxy:latest'
  links:
    - fetcher
  restart: always
  
processor:
  image: 'binux/pyspider:latest'
  command: '--projectdb "sqlalchemy+postgresql+projectdb://binux@10.21.0.7/projectdb" --message-queue "redis://10.21.0.7:6379/1" processor'
  cpu_shares: 512
  mem_limit: 256m
  restart: always
  
result-worker:
  image: 'binux/pyspider:latest'
  command: '--taskdb "sqlalchemy+postgresql+taskdb://binux@10.21.0.7/taskdb"  --projectdb "sqlalchemy+postgresql+projectdb://binux@10.21.0.7/projectdb" --resultdb "sqlalchemy+postgresql+resultdb://binux@10.21.0.7/resultdb" --message-queue "redis://10.21.0.7:6379/1" result_worker'
  cpu_shares: 512
  mem_limit: 256m
  restart: always
  
webui:
  image: 'binux/pyspider:latest'
  command: '--taskdb "sqlalchemy+postgresql+taskdb://binux@10.21.0.7/taskdb"  --projectdb "sqlalchemy+postgresql+projectdb://binux@10.21.0.7/projectdb" --resultdb "sqlalchemy+postgresql+resultdb://binux@10.21.0.7/resultdb" --message-queue "redis://10.21.0.7:6379/1" webui --max-rate 0.2 --max-burst 3 --scheduler-rpc "http://o4.i.binux.me:23333/" --fetcher-rpc "http://fetcher/"'

  cpu_shares: 512
  environment:
    - 'EXCLUDE_PORTS=24444,25555,23333'
  links:
    - 'fetcher-lb:fetcher'
  mem_limit: 256m
  restart: always
webui-lb:
  image: 'dockercloud/haproxy:latest'
  links:
    - webui
  restart: always
  
nginx:
  image: 'nginx'
  links:
    - 'webui-lb:HAPROXY'
  ports:
    - '0.0.0.0:80:80'
  volumes:
    - /home/binux/nfs/profile/nginx/nginx.conf:/etc/nginx/nginx.conf
    - /home/binux/nfs/profile/nginx/conf.d/:/etc/nginx/conf.d/
  restart: always
```

With the config, you can change the scale by `docker-compose scale phantomjs=2 processor=2 webui=4` when you need. 

#### load balance

phantomjs-lb, fetcher-lb, webui-lb are automaticlly configed haproxy, allow any number of upstreams.

#### phantomjs

phantomjs have memory leak issue, memory limit applied, and it's recommended to restart it every hour.

#### fetcher

fetcher is implemented with aync IO, it supportes 100 concurrent connections. If the upstream queue are not choked, one fetcher should be enough.

#### processor

processor is CPU bound component, recommended number of instance is number of CPU cores + 1~2 or CPU cores * 10%~15% when you have more then 20 cores.

#### result-worker

If you didn't override result-worker, it only write results into database, and should be very fast.