docker-composeでコンテナをスケールさせる方法のメモでやった、docker-composeの --scaleオプションで用意した複数のNginxコンテナにラウンドロビン形式でバランシングを行う方法のメモ

ソース

nobiki/ha-proxy-sample

docker-compose.yml

haproxyイメージを使います

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
version: '3'

services:

  # Webサーバ
  web:
    image: nginx:alpine

  # ロードバランサ
  haproxy:
    image: haproxy:2.1.7-alpine
    ports:
      - 80:80
    volumes:
      - ./haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg
    depends_on:
      - web

haproxy.cfg

webサーバを3台スケール --scale web=3とする前提でcfgファイルを作成しました。詳細なマニュアルはこのあたりにあります

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
defaults
    timeout connect 5s
    timeout client 5s
    timeout server 30s

frontend web_proxy
    bind *:80
    use_backend web-server

backend web-server
    balance roundrobin

    server web-server1 ha-proxy_web_1:80 check inter 2s
    server web-server2 ha-proxy_web_2:80 check inter 2s
    server web-server3 ha-proxy_web_3:80 check inter 2s

    mode http
    option forwardfor

COMPOSE_PROJECT_NAME

1
2
3
server web-server1 ha-proxy_web_1:80 check inter 2s
server web-server2 ha-proxy_web_2:80 check inter 2s
server web-server3 ha-proxy_web_3:80 check inter 2s

haproxy.cfgで、serverを上記のように設定したので、 COMPOSE_PROJECT_NAME=ha-proxyとします（デフォルトはディレクトリ名）

1
export COMPOSE_PROJECT_NAME=ha-proxy

up

1
2
3
4
5
6
7
// webをscaleさせる
$ docker-compose up -d --scale web=3
Creating network "ha-proxy_default" with the default driver
Creating ha-proxy_web_1 ... done
Creating ha-proxy_web_2 ... done
Creating ha-proxy_web_3 ... done
Creating ha-proxy_haproxy_1 ... done

upした後、ブラウザで適当にF5連打してログを観察します

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
// 振り分けされているのをログで確認
$ docker-compose logs -f
Attaching to ha-proxy_haproxy_1, ha-proxy_web_3, ha-proxy_web_1, ha-proxy_web_2
haproxy_1  | [NOTICE] 166/074055 (1) : New worker #1 (6) forked
web_1      | 172.23.0.5 - - [15/Jun/2020:07:41:24 +0000] "GET / HTTP/1.1" 200 612 "-"
web_2      | 172.23.0.5 - - [15/Jun/2020:07:41:25 +0000] "GET / HTTP/1.1" 304 0 "-"
web_3      | 172.23.0.5 - - [15/Jun/2020:07:41:25 +0000] "GET / HTTP/1.1" 304 0 "-"
web_1      | 172.23.0.5 - - [15/Jun/2020:07:41:26 +0000] "GET / HTTP/1.1" 304 0 "-"
web_2      | 172.23.0.5 - - [15/Jun/2020:07:41:26 +0000] "GET / HTTP/1.1" 304 0 "-"
web_3      | 172.23.0.5 - - [15/Jun/2020:07:41:26 +0000] "GET / HTTP/1.1" 304 0 "-"
web_1      | 172.23.0.5 - - [15/Jun/2020:07:41:26 +0000] "GET / HTTP/1.1" 304 0 "-"
web_2      | 172.23.0.5 - - [15/Jun/2020:07:41:26 +0000] "GET / HTTP/1.1" 304 0 "-"
web_3      | 172.23.0.5 - - [15/Jun/2020:07:41:26 +0000] "GET / HTTP/1.1" 304 0 "-"
web_1      | 172.23.0.5 - - [15/Jun/2020:07:41:27 +0000] "GET / HTTP/1.1" 304 0 "-"
web_2      | 172.23.0.5 - - [15/Jun/2020:07:41:27 +0000] "GET / HTTP/1.1" 304 0 "-"
web_3      | 172.23.0.5 - - [15/Jun/2020:07:41:27 +0000] "GET / HTTP/1.1" 304 0 "-"
web_1      | 172.23.0.5 - - [15/Jun/2020:07:41:27 +0000] "GET / HTTP/1.1" 304 0 "-"
web_2      | 172.23.0.5 - - [15/Jun/2020:07:41:27 +0000] "GET / HTTP/1.1" 304 0 "-"
web_3      | 172.23.0.5 - - [15/Jun/2020:07:41:28 +0000] "GET / HTTP/1.1" 304 0 "-"
web_1      | 172.23.0.5 - - [15/Jun/2020:07:41:28 +0000] "GET / HTTP/1.1" 304 0 "-"
web_2      | 172.23.0.5 - - [15/Jun/2020:07:41:28 +0000] "GET / HTTP/1.1" 304 0 "-"
web_3      | 172.23.0.5 - - [15/Jun/2020:07:41:28 +0000] "GET / HTTP/1.1" 304 0 "-"