藍綠部署
藍綠部署的重點在於以下特點
1. 藍色版本和綠色版本同時存在
2. 實際運作的環境為藍或則綠,只能為其中之一,透過開關控制
##優點和缺點分析:優點在於它的速度和回滾。而缺點也顯而易見。可以快速回滾是因為有兩套環境同時存在的緣故,所以複雜度和需要的資源會增多,因為其有兩套環境。另外雖然速度有所提高,但是在實現的過程中,開關的控制,無論多快的切換速度,如果不結合其他的技術,還是無法做到完全無縫切換。
模擬藍綠部署
接下來我們使用nginx的upstream來簡單模擬藍綠部署的場景。具體場景如下, 目前活躍的是藍色版本,透過調整nginx設定,將綠色版本設定為當前活躍版本。事前準備
事前在7001/7002兩個連接埠分別啟動兩個服務,用於顯示不同訊息,為了示範方便,使用tornado做了一個映像,透過docker容器啟動時傳遞的參數不同用於顯示服務的不同。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"
執行日誌
[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://192.168.163.117:7001 hello, service :hello blue/green service: v1 in 7001 [root@kong ~]# curl http://192.168.163.117:7002 hello, service :hello blue/green service: v2 in 7002 [root@kong ~]#
啟動nginx
[root@kong ~]# docker run -p 9080:80 --name nginx-blue-green -d nginx d3b7098c44890c15918dc47616b67e5e0eb0da7a443eac266dbf26d55049216a [root@kong ~]# docker ps |grep nginx-blue-green d3b7098c4489 nginx "nginx -g 'daemon ..." 10 seconds ago up 9 seconds 0.0.0.0:9080->80/tcp nginx-blue-green [root@kong ~]#
nginx程式碼段
#準備如下nginx程式碼段將其新增至nginx的/etc/nginx/conf.d/default.conf中, 模擬方式很簡單,透過down表示流量為零(nginx中無法將weight設為零),開始的時候100%的流量都發到藍色版本。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; } }
修改default.conf的方法
可以透過在容器中安裝vim達到效果,也可以在本地修改然後透過docker cp傳入,或直接sed修改都可。如果在容器中安裝vim,使用下列方式即可[root@kong ~]# docker exec -it nginx-lb sh # apt-get update ...省略 # apt-get install vim ...省略
#修改前
# cat default.conf server { 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$fastcgi_script_name; # include fastcgi_params; #} # deny access to .htaccess files, if apache's document root # concurs with nginx's one # #location ~ /\.ht { # deny all; #} } #
已修改後
# cat default.conf upstream nginx_blug_green { server 192.168.163.117:7001 weight=100; server 192.168.163.117:7002 down; } server { listen 80; server_name www.liumiao.cn 192.168.163.117; #charset koi8-r; #access_log /var/log/nginx/host.access.log main; location / { #root /usr/share/nginx/html; #index index.html index.htm; proxy_pass http://nginx_blug_green; } #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # error_page 500 502 503 504 /50x.html; location = /50x.html { root /usr/share/nginx/html; } # proxy the php scripts to apache listening on 127.0.0.1:80 # #location ~ \.php$ { # 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; #} } #
重新載入nginx設定
# nginx -s reload 2018/05/28 04:39:47 [notice] 321#321: signal process started #
確認結果
#10次呼叫全部輸出的都是v1 in 7001
#[root@kong ~]# cnt=0; while [ $cnt -lt 10 ]> do> curl
> let cnt> done#####藍綠部署:切換到綠色版本#########透過調整default.conf的weight,然後執行nginx -s reload的方式,在不停止nginx服務的方式下可動態的切換到綠色版本,目標將會將全部的流量都輸出v2 in 7002##########修改default .conf的方法#########只需要將upstream中的server的權重做如下調整:###hello, service :hello blue/green service: v1 in 7001
hello, service :hello blue/green service: v1 in 7001
hello, service :hello blue/green service: v1 in 7001
hello, service :#hello, service : hello blue/green service: v1 in 7001
hello, service :hello blue/green service: v1 in 7001
hello, service :hello blue/green service: v1 in 7001
hello, service :hello blue /green service: v1 in 7001
hello, service :hello blue/green service: v1 in 7001
hello, service :hello blue/green service: v1 in 7001
hello, service :hello blue/green service: v1 in 7001
[root@kong ~]
upstream nginx_blug_green { server 192.168.163.117:7001 down; server 192.168.163.117:7002 weight=100; }
# nginx -s reload 2018/05/28 05:01:28 [notice] 330#330: signal process started #
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