Docker : le huitième pas.

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Attention ceci est mon brouillon avant de faire une belle documentation sur Docker (il y a à boire et à manger).

Je me suis planté complètement avec HAProxy, pour l’instant je n’ai pas compris mes erreurs car je n’ai pas réussi à avoir accès au logs. Mon étape va être de voir si avec l’autre server de répartition de charge : nginx, j’arrive à faire mieux.

On commence par le téléchargement de la version :

[root@localhost ~]# docker pull nginx
Using default tag: latest
latest: Pulling from library/nginx
efd26ecc9548: Already exists 
a3ed95caeb02: Pull complete 
83f52fbfa5f8: Pull complete 
fa664caa1402: Pull complete 
Digest: sha256:12127e07a75bda1022fbd4ea231f5527a1899aad4679e3940482db3b57383b1d
Status: Downloaded newer image for nginx:latest

Ensuite on doit faire la configuration, on va faire une configuration en mode « stream » car notre protocole n’est pas du HTTP, HTTPS ou SMTP.

Et c’est partie pour une première version :

[root@localhost ~]# cat nginx.conf 
worker_processes  4;

events {
    worker_connections  8192;
}

http {
    include       mime.types;
    default_type  application/octet-stream;
}

stream {
    upstream stream_backend {
	server my-server4-1:8080 weight=5;
        server my-server4-2:8081;
        server my-server4-3:8082;
        server my-server4-4:8083;
    }
    server {
        listen     80;
        proxy_pass stream_backend;
    }
}

[root@localhost ~]# docker run --name mon-nginx-v1 --link my-server4-1 --link my-server4-2 --link my-server4-3 --link my-server4-4 -p 80:80 -v /root/nginx.conf:/etc/nginx/nginx.conf:ro -d nginx 
95adc730e7b2e1164d1c25aee18b0077e122f02aa8197d52f7ed6c3cfa8ca77a
[root@localhost ~]# docker logs 95adc730e7b2e1164d1c25aee18b0077e122f02aa8197d52f7ed6c3cfa8ca77a
[root@localhost ~]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                         NAMES
95adc730e7b2        nginx               "nginx -g 'daemon off"   12 seconds ago      Up 12 seconds       0.0.0.0:80->80/tcp, 443/tcp   mon-nginx-v1
78f6bc54152e        my-server4          "/sbin/server4"          4 hours ago         Up 4 hours          0.0.0.0:8083->80/tcp          my-server4-4
fce6865343f1        my-server4          "/sbin/server4"          4 hours ago         Up 4 hours          0.0.0.0:8082->80/tcp          my-server4-3
a75937eb980d        my-server4          "/sbin/server4"          4 hours ago         Up 4 hours          0.0.0.0:8081->80/tcp          my-server4-2
eacf3e4bc897        my-server4          "/sbin/server4"          4 hours ago         Up 4 hours          0.0.0.0:8080->80/tcp          my-server4-1
2fc533c55725        postgres            "/docker-entrypoint.s"   14 hours ago        Up 14 hours         0.0.0.0:5432->5432/tcp        postgres2
[root@localhost ~]# telnet 127.0.0.1 80
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
Connection closed by foreign host.

J’ai l’impression que cela va être long 🙁 Par contre la bonne nouvelle c’est qu’il y a des logs !

[root@localhost ~]# docker logs 95adc730e7b2e1164d1c25aee18b0077e122f02aa8197d52f7ed6c3cfa8ca77a
2016/04/15 10:11:32 [error] 5#5: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.17.0.1, server: 0.0.0.0:80, upstream: "172.17.0.3:8080", bytes from/to client:0/0, bytes from/to upstream:0/0
2016/04/15 10:11:32 [error] 5#5: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.17.0.1, server: 0.0.0.0:80, upstream: "172.17.0.4:8081", bytes from/to client:0/0, bytes from/to upstream:0/0
2016/04/15 10:11:32 [error] 5#5: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.17.0.1, server: 0.0.0.0:80, upstream: "172.17.0.5:8082", bytes from/to client:0/0, bytes from/to upstream:0/0
2016/04/15 10:11:32 [error] 5#5: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.17.0.1, server: 0.0.0.0:80, upstream: "172.17.0.6:8083", bytes from/to client:0/0, bytes from/to upstream:0/0
[root@localhost ~]# telnet 172.17.0.3 8080
Trying 172.17.0.3...
telnet: connect to address 172.17.0.3: Connection refused
[root@localhost ~]# telnet 127.0.0.1 8080
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.

HELLO
IP

eth0
QUIT
Connection closed by foreign host.

J’ai compris je dois toujours attaquer le port 80 car je dois penser en terme de container. Et à l’intérieur du container c’est le port 80 qui est ouvert.

[root@localhost ~]# cat nginx.conf
worker_processes  4;

events {
    worker_connections  8192;
}

http {
    include       mime.types;
    default_type  application/octet-stream;
}

stream {
    upstream stream_backend {
	server my-server4-1:80 weight=5;
        server my-server4-2:80;
        server my-server4-3:80;
        server my-server4-4:80;
    }
    server {
        listen     80;
        proxy_pass stream_backend;
    }
}

[root@localhost ~]# docker run --name mon-nginx-v2 --link my-server4-1 --link my-server4-2 --link my-server4-3 --link my-server4-4 -p 80:80 -v /root/nginx.conf:/etc/nginx/nginx.conf:ro -d nginx 
304ce9e61abbd21e413a465018d79c285877b0fcc6bcb229444c8883b7e8e54d
[root@localhost ~]# telnet 127.0.0.1 80
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.

HELLO
IP

eth0
INTERFACE

172.17.0.3
QUIT
Connection closed by foreign host.
[root@localhost ~]# telnet 127.0.0.1 80
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.

HELLO
INTERFACE

172.17.0.3
QUIT
Connection closed by foreign host.
[root@localhost ~]# telnet 127.0.0.1 80
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.

HELLO
INTERFACE

172.17.0.4
QUIT
Connection closed by foreign host.
[root@localhost ~]# docker logs 304ce9e61abbd21e413a465018d79c285877b0fcc6bcb229444c8883b7e8e54d

Champagne ! Cela fonctionne quand je fais un telnet, je tombe de façon aléatoire sur un des serveurs. Par contre dans les logs je n’ai rien si cela fonctionne, il va falloir que je comprenne comment fonctionne les logs sous Docker. Je vais d’abord revenir sur HAProxy afin de voir si c’est pas le mauvais port qui causait un problème.

[root@localhost ~]# cat haproxy.cfg 
global
    maxconn 400

defaults
    log global
    mode    tcp
    option  tcplog
    option  dontlognull
    retries 4
    maxconn 200
    timeout connect  5000
    timeout client  50000
    timeout server  50000

frontend http-in
    bind *:80
    log 127.0.0.1 local0	
    default_backend serveur

backend serveur
        mode tcp
        balance roundrobin
        server server1 my-server4-1:80
        server server2 my-server4-2:80
        server server3 my-server4-3:80
        server server4 my-server4-4:80

[root@localhost ~]# docker build -t my-haproxy-v15 .
Sending build context to Docker daemon 131.1 kB
Step 1 : FROM haproxy:1.5
 ---> 011e001101c0
Step 2 : COPY ./haproxy.cfg /usr/local/etc/haproxy/haproxy.cfg
 ---> 596df11f08ac
Removing intermediate container 40b11ef3c4bc
Step 3 : EXPOSE 80
 ---> Running in b955fb86c4b3
 ---> 921af748062e
Removing intermediate container b955fb86c4b3
Successfully built 921af748062e

[root@localhost ~]# docker run -d --link my-server4-1 --link my-server4-2 --link my-server4-3 --link my-server4-4 -p 80:80 --name mon-haproxy-v15b my-haproxy-v15
1fd7d0db42301042d221e4765a38480cf91281be6ac859069894fa96856f311f

[root@localhost ~]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                    NAMES
1fd7d0db4230        my-haproxy-v15      "/docker-entrypoint.s"   5 seconds ago       Up 4 seconds        0.0.0.0:80->80/tcp       mon-haproxy-v15b
78f6bc54152e        my-server4          "/sbin/server4"          4 hours ago         Up 4 hours          0.0.0.0:8083->80/tcp     my-server4-4
fce6865343f1        my-server4          "/sbin/server4"          4 hours ago         Up 4 hours          0.0.0.0:8082->80/tcp     my-server4-3
a75937eb980d        my-server4          "/sbin/server4"          4 hours ago         Up 4 hours          0.0.0.0:8081->80/tcp     my-server4-2
eacf3e4bc897        my-server4          "/sbin/server4"          4 hours ago         Up 4 hours          0.0.0.0:8080->80/tcp     my-server4-1
2fc533c55725        postgres            "/docker-entrypoint.s"   15 hours ago        Up 15 hours         0.0.0.0:5432->5432/tcp   postgres2

[root@localhost ~]# telnet 127.0.0.1 80
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.

HELLO
IP

eth0
INTERFACE

172.17.0.3
QUIT
Connection closed by foreign host.
[root@localhost ~]# telnet 127.0.0.1 80
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.

HELLO
INTERFACE

172.17.0.4
QUIT
Connection closed by foreign host.
[root@localhost ~]# docker logs 1fd7d0db42301042d221e4765a38480cf91281be6ac859069894fa96856f311f
haproxy-systemd-wrapper: executing /usr/local/sbin/haproxy -p /run/haproxy.pid -f /usr/local/etc/haproxy/haproxy.cfg -Ds 

Super cela fonctionne aussi avec HAProxy, reste maintenant à voir les logs !

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