nginx application: using nginx for blue-green deployment

This article mainly introduces the nginx application: using nginx for blue and green deployment has a certain reference value. Now I share it with you. Friends in need can refer to it.

This article introduces the blue and green deployment. Green deployment and how to use nginx to simulate blue-green deployment in the simplest way

Blue-green deployment

The focus of blue-green deployment lies in the following features
1. Blue version and green version exist at the same time
2. The actual running environment is blue or green, it can only be one of them, controlled by the switch

优点和缺点分析：优点在于它的速度和回滚。而缺点也显而易见。可以快速回滚是因为有两套环境同时存在的缘故，所以复杂度和需要的资源会增多，因为其有两套环境。 
 另外虽然速度有所提高，但是在实现的过程中，开关的控制，无论多快的切换速度，如果不结合其他的技术，还是无法做到完全无缝切换。

Simulate blue-green deployment

Next we use nginx upstream to simply simulate it Blue-green deployment scenario. The specific scenario is as follows. The blue version is currently active. By adjusting the nginx settings, the green version is set as the currently active version.

##routerUser passed http://localhost:8090 Visit the microservice under this kind of deploymentBlue versionThe current active blue version provides services on port 7001. The prompt information is "Hello blue/green service: v1 in 7001"Green versionThe green version that will be released soon will provide services on port 7002. The prompt information is" Hello blue/green service: v2 in 7002”

Version	Description

Preparation in advance

Start two services on the two ports 7001/7002 in advance for display For different information, for the convenience of demonstration, I used tornado to make an image, and the different parameters passed when starting the docker container are used to display the differences in services.

docker run -d -p 7001:8080 liumiaocn/tornado:latest python /usr/local/bin/daemon.py "Hello blue/green service： v1 in 7001"docker run -d -p 7002:8080 liumiaocn/tornado:latest python /usr/local/bin/daemon.py "Hello blue/green service： v2 in 7002"

Execution log

[root@kong ~]# docker run -d -p 7001:8080 liumiaocn/tornado:latest python /usr/local/bin/daemon.py "Hello blue/green service： v1 in 7001"70c74dc8e43d5635983f7240deb63a3fc0599d5474454c3bc5197aa5c0017348
[root@kong ~]# docker run -d -p 7002:8080 liumiaocn/tornado:latest python /usr/local/bin/daemon.py "Hello blue/green service： v2 in 7002"6c5c2ea322d4ac17b90feefb96e3194ec8adecedaa4c944419316a2e4bf07117
[root@kong ~]# curl http://192.168.163.117:7001Hello, Service :Hello blue/green service： v1 in 7001[root@kong ~]# curl http://192.168.163.117:7002Hello, Service :Hello blue/green service： v2 in 7002[root@kong ~]#

Start nginx

[root@kong ~]# docker run -p 9080:80 --name nginx-blue-green -d nginxd3b7098c44890c15918dc47616b67e5e0eb0da7a443eac266dbf26d55049216a
[root@kong ~]# docker ps |grep nginx-blue-greend3b7098c4489        nginx                      "nginx -g 'daemon ..."   10 seconds ago       Up 9 seconds        0.0.0.0:9080->80/tcp     nginx-blue-green
[root@kong ~]#

nginx code segment

Prepare the following nginx code segment and add it to nginx’s /etc/nginx/ In conf.d/default.conf, the simulation method is very simple. Use down to indicate that the traffic is zero (weight cannot be set to zero in nginx). At the beginning, 100% of the traffic is sent to the blue version.

http {
upstream nginx_blug_green {    server 192.168.163.117:7001 weight=100;    server 192.168.163.117:7002 down;
}server {
    listen       80;
    server_name  www.liumiao.cn 192.168.163.117;
    location / {
        proxy_pass http://nginx_blug_green;
    }

}

How to modify default.conf

You can achieve the effect by installing vim in the container, you can also modify it locally and pass it in through docker cp, or modify it directly with sed. If you install vim in a container, use the following method

[root@kong ~]# docker exec -it nginx-lb sh# apt-get update...省略# apt-get install vim...省略

Before modification

# cat default.confserver {
    listen       80;
    server_name  localhost;    #charset koi8-r;
    #access_log  /var/log/nginx/host.access.log  main;

    location / {
        root   /usr/share/nginx/html;        index  index.html index.htm;
    }    #error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }    # proxy the PHP scripts to Apache listening on 127.0.0.1:80
    #
    #location ~ \.php$ {
    #    proxy_pass   http://127.0.0.1;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    #location ~ \.php$ {
    #    root           html;
    #    fastcgi_pass   127.0.0.1:9000;
    #    fastcgi_index  index.php;
    #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
    #    include        fastcgi_params;
    #}

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #    deny  all;
    #}}#

After modification

# cat default.confupstream nginx_blug_green {    server 192.168.163.117:7001 weight=100;    server 192.168.163.117:7002 down;
}server {
    listen       80;
    server_name  www.liumiao.cn 192.168.163.117;    #charset koi8-r;
    #access_log  /var/log/nginx/host.access.log  main;

    location / {        #root   /usr/share/nginx/html;
        #index  index.html index.htm;
        proxy_pass http://nginx_blug_green;
    }    #error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }    # proxy the PHP scripts to Apache listening on 127.0.0.1:80
    #
    #location ~ \.php$ {
    #    proxy_pass   http://127.0.0.1;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    #location ~ \.php$ {
    #    root           html;
    #    fastcgi_pass   127.0.0.1:9000;
    #    fastcgi_index  index.php;
    #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
    #    include        fastcgi_params;
    #}

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #    deny  all;
    #}}#

Reload nginx settings

# nginx -s reload2018/05/28 04:39:47 [notice] 321#321: signal process started#

Confirm Result

The output of all 10 calls is v1 in 7001

[root@kong ~]# cnt=0; while [ $cnt -lt 10 ]> do> curl http://localhost:9080> let cnt++
> done
Hello, Service :Hello blue/green service： v1 in 7001Hello, Service :Hello blue/green service： v1 in 7001Hello, Service :Hello blue/green service： v1 in 7001Hello, Service :Hello blue/green service： v1 in 7001Hello, Service :Hello blue/green service： v1 in 7001Hello, Service :Hello blue/green service： v1 in 7001Hello, Service :Hello blue/green service： v1 in 7001Hello, Service :Hello blue/green service： v1 in 7001Hello, Service :Hello blue/green service： v1 in 7001Hello, Service :Hello blue/green service： v1 in 7001[root@kong ~]#

Blue-green deployment: switch to the green version

By adjusting the weight of default.conf, and then executing nginx -s reload method can dynamically switch to the green version without stopping the nginx service. The target will output all traffic to v2 in 7002

How to modify default.conf

Only need to adjust the weight of the server in upstream as follows:

upstream nginx_blug_green {    server 192.168.163.117:7001 down;    server 192.168.163.117:7002 weight=100;
}

Reload nginx settings

# nginx -s reload2018/05/28 05:01:28 [notice] 330#330: signal process started#

Confirm the result

[root@kong ~]# cnt=0; while [ $cnt -lt 10 ]; do curl http://localhost:9080; let cnt++; doneHello, Service :Hello blue/green service： v2 in 7002Hello, Service :Hello blue/green service： v2 in 7002Hello, Service :Hello blue/green service： v2 in 7002Hello, Service :Hello blue/green service： v2 in 7002Hello, Service :Hello blue/green service： v2 in 7002Hello, Service :Hello blue/green service： v2 in 7002Hello, Service :Hello blue/green service： v2 in 7002Hello, Service :Hello blue/green service： v2 in 7002Hello, Service :Hello blue/green service： v2 in 7002Hello, Service :Hello blue/green service： v2 in 7002[root@kong ~]#

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nginx application: using nginx for canary publishing

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