👨🏾‍🤝‍👨🏽 👜 🧦 最低工资的蓝绿色部署 💇🏽 👩🏼‍💻 🛸

在本文中，我们使用bash，ssh，docker和nginx来组织Web应用程序的无缝布局。蓝绿色部署是一项技术，使您可以立即更新应用程序而不会拒绝任何请求。它是零停机时间部署策略之一，最适合具有一个实例的应用程序，但是可以并行加载第二个可立即运行的实例。

假设您有一个Web应用程序，许多客户端都在使用该应用程序，并且绝对不能躺下几秒钟。您确实需要推出库更新，修复错误或新的出色功能。在正常情况下，您将需要停止应用程序，将其替换并重新启动。对于docker，您可以先替换，然后重新启动，但是仍然会有一段时间不处理对应用程序的请求，因为通常应用程序会花费一些时间来启动。如果启动但结果却不起作用怎么办？这是任务，让我们以最少的手段并尽可能地优雅地解决它。

免责声明：本文的大部分内容都是以实验形式提供的-以控制台会话记录的形式。希望它不会很难理解，并且此代码本身也有很多文档。对于大气，可以想象这些不仅是代码片段，还包括来自“铁”电传打字机的纸张。

在每个部分的开头，都介绍了仅通过阅读代码Google很难获得的有趣技术。如果您听不懂其他内容，请使用google并签入explainshell（很幸运，由于解除了对电报的阻止，它再次起作用了）。未搜索到的内容-在评论中询问。我很高兴添加适当的部分“有趣的技术”。

让我们开始吧。

$ mkdir blue-green-deployment && cd $_

服务

让我们创建一个实验服务并将其放置在容器中。

有趣的技术

cat << EOF > file-name (Here Document + I/O Redirection) — . , bash /dev/stdin EOF file-name.
wget -qO- URL (explainshell) — HTTP /dev/stdout ( curl URL).

, Python. . , ( ), .

$ cat << EOF > uptimer.py

from http.server import BaseHTTPRequestHandler, HTTPServer
from time import monotonic

app_version = 1
app_name = f'Uptimer v{app_version}.0'
loading_seconds = 15 - app_version * 5

class Handler(BaseHTTPRequestHandler):
    def do_GET(self):
        if self.path == '/':
            try:
                t = monotonic() - server_start
                if t < loading_seconds:
                    self.send_error(503)
                else:
                    self.send_response(200)
                    self.send_header('Content-Type', 'text/html')
                    self.end_headers()
                    response = f'<h2>{app_name} is running for {t:3.1f} seconds.</h2>\n'
                    self.wfile.write(response.encode('utf-8'))
            except Exception:
                self.send_error(500)
        else:
            self.send_error(404)

httpd = HTTPServer(('', 8080), Handler)
server_start = monotonic()
print(f'{app_name} (loads in {loading_seconds} sec.) started.')
httpd.serve_forever()

EOF

$ cat << EOF > Dockerfile
FROM python:alpine
EXPOSE 8080
COPY uptimer.py app.py
CMD [ "python", "-u", "./app.py" ]
EOF

$ docker build --tag uptimer .
Sending build context to Docker daemon  39.42kB
Step 1/4 : FROM python:alpine
 ---> 8ecf5a48c789
Step 2/4 : EXPOSE 8080
 ---> Using cache
 ---> cf92d174c9d3
Step 3/4 : COPY uptimer.py app.py
 ---> a7fbb33d6b7e
Step 4/4 : CMD [ "python", "-u", "./app.py" ]
 ---> Running in 1906b4bd9fdf
Removing intermediate container 1906b4bd9fdf
 ---> c1655b996fe8
Successfully built c1655b996fe8
Successfully tagged uptimer:latest

$ docker run --rm --detach --name uptimer --publish 8080:8080 uptimer
8f88c944b8bf78974a5727070a94c76aa0b9bb2b3ecf6324b784e782614b2fbf

$ docker ps
CONTAINER ID        IMAGE               COMMAND                CREATED             STATUS              PORTS                    NAMES
8f88c944b8bf        uptimer             "python -u ./app.py"   3 seconds ago       Up 5 seconds        0.0.0.0:8080->8080/tcp   uptimer

$ docker logs uptimer
Uptimer v1.0 (loads in 10 sec.) started.

$ wget -qSO- http://localhost:8080
  HTTP/1.0 503 Service Unavailable
  Server: BaseHTTP/0.6 Python/3.8.3
  Date: Sat, 22 Aug 2020 19:52:40 GMT
  Connection: close
  Content-Type: text/html;charset=utf-8
  Content-Length: 484

$ wget -qSO- http://localhost:8080
  HTTP/1.0 200 OK
  Server: BaseHTTP/0.6 Python/3.8.3
  Date: Sat, 22 Aug 2020 19:52:45 GMT
  Content-Type: text/html
<h2>Uptimer v1.0 is running for 15.4 seconds.</h2>

$ docker rm --force uptimer
uptimer

-

, , - , . - nginx -. - . .

- docker network. , -, .

- , docker network - , --publish, -.

- 80, , . 80- , --publish 80:80 --publish ANY_FREE_PORT:80.

" docker-, , IP . " ( "Networking with standalone containers", "Use user-defined bridge networks", 5 -).

$ docker network create web-gateway
5dba128fb3b255b02ac012ded1906b7b4970b728fb7db3dbbeccc9a77a5dd7bd

$ docker run --detach --rm --name uptimer --network web-gateway uptimer
a1105f1b583dead9415e99864718cc807cc1db1c763870f40ea38bc026e2d67f

$ docker run --rm --network web-gateway alpine wget -qO- http://uptimer:8080
<h2>Uptimer v1.0 is running for 11.5 seconds.</h2>

$ docker run --detach --publish 80:80 --network web-gateway --name reverse-proxy nginx:alpine
80695a822c19051260c66bf60605dcb4ea66802c754037704968bc42527bf120

$ docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS              PORTS                NAMES
80695a822c19        nginx:alpine        "/docker-entrypoint.…"   27 seconds ago       Up 25 seconds       0.0.0.0:80->80/tcp   reverse-proxy
a1105f1b583d        uptimer             "python -u ./app.py"     About a minute ago   Up About a minute   8080/tcp             uptimer

$ cat << EOF > uptimer.conf
server {
    listen 80;
    location / {
        proxy_pass http://uptimer:8080;
    }
}
EOF

$ docker cp ./uptimer.conf reverse-proxy:/etc/nginx/conf.d/default.conf

$ docker exec reverse-proxy nginx -s reload
2020/06/23 20:51:03 [notice] 31#31: signal process started

$ wget -qSO- http://localhost
  HTTP/1.1 200 OK
  Server: nginx/1.19.0
  Date: Sat, 22 Aug 2020 19:56:24 GMT
  Content-Type: text/html
  Transfer-Encoding: chunked
  Connection: keep-alive
<h2>Uptimer v1.0 is running for 104.1 seconds.</h2>

( startup performance) .

echo 'my text' | docker exec -i my-container sh -c 'cat > /my-file.txt' — my text /my-file.txt my-container.
cat > /my-file.txt — /dev/stdin.

$ sed -i "s/app_version = 1/app_version = 2/" uptimer.py

$ docker build --tag uptimer .
Sending build context to Docker daemon  39.94kB
Step 1/4 : FROM python:alpine
 ---> 8ecf5a48c789
Step 2/4 : EXPOSE 8080
 ---> Using cache
 ---> cf92d174c9d3
Step 3/4 : COPY uptimer.py app.py
 ---> 3eca6a51cb2d
Step 4/4 : CMD [ "python", "-u", "./app.py" ]
 ---> Running in 8f13c6d3d9e7
Removing intermediate container 8f13c6d3d9e7
 ---> 1d56897841ec
Successfully built 1d56897841ec
Successfully tagged uptimer:latest

$ docker run --detach --rm --name uptimer_BLUE --network web-gateway uptimer
96932d4ca97a25b1b42d1b5f0ede993b43f95fac3c064262c5c527e16c119e02

$ docker logs uptimer_BLUE
Uptimer v2.0 (loads in 5 sec.) started.

$ docker run --rm --network web-gateway alpine wget -qO- http://uptimer_BLUE:8080
<h2>Uptimer v2.0 is running for 23.9 seconds.</h2>

$ sed s/uptimer/uptimer_BLUE/ uptimer.conf | docker exec --interactive reverse-proxy sh -c 'cat > /etc/nginx/conf.d/default.conf'

$ docker exec reverse-proxy cat /etc/nginx/conf.d/default.conf
server {
    listen 80;
    location / {
        proxy_pass http://uptimer_BLUE:8080;
    }
}

$ docker exec reverse-proxy nginx -s reload
2020/06/25 21:22:23 [notice] 68#68: signal process started

$ wget -qO- http://localhost
<h2>Uptimer v2.0 is running for 63.4 seconds.</h2>

$ docker rm -f uptimer
uptimer

$ wget -qO- http://localhost
<h2>Uptimer v2.0 is running for 84.8 seconds.</h2>

$ docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS              PORTS                NAMES
96932d4ca97a        uptimer             "python -u ./app.py"     About a minute ago   Up About a minute   8080/tcp             uptimer_BLUE
80695a822c19        nginx:alpine        "/docker-entrypoint.…"   8 minutes ago        Up 8 minutes        0.0.0.0:80->80/tcp   reverse-proxy

, , . (, CI-) .

, localhost localhost , . :

$ ssh production-server docker image ls
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE

$ docker image save uptimer | ssh production-server 'docker image load'
Loaded image: uptimer:latest

$ ssh production-server docker image ls
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
uptimer             latest              1d56897841ec        5 minutes ago       78.9MB

docker save .tar , 1.5 , . :

$ docker image save uptimer | gzip | ssh production-server 'zcat | docker image load'
Loaded image: uptimer:latest

, (, ):

$ docker image save uptimer | gzip | pv | ssh production-server 'zcat | docker image load'
25,7MiB 0:01:01 [ 425KiB/s] [                   <=>    ]
Loaded image: uptimer:latest

: SSH , ~/.ssh/config.

docker image save/load — , . :

Container Registry ( ).
docker daemon :
1. DOCKER_HOST.
2. -H --host docker-compose.
3. docker context

( ) How to deploy on remote Docker hosts with docker-compose.

`deploy.sh`

, . top-level , , .

${parameter?err_msg} — bash- (aka parameter substitution). parameter , err_msg 1.
docker --log-driver journald — -, - . , production- .

deploy() {
    local image_name=${1?"Usage: ${FUNCNAME[0]} image_name"}

    ensure-reverse-proxy || return 2
    if get-active-slot $image_name
    then
        local OLD=${image_name}_BLUE
        local new_slot=GREEN
    else
        local OLD=${image_name}_GREEN
        local new_slot=BLUE
    fi
    local NEW=${image_name}_${new_slot}
    echo "Deploying '$NEW' in place of '$OLD'..."
    docker run \
        --detach \
        --restart always \
        --log-driver journald \
        --name $NEW \
        --network web-gateway \
        $image_name || return 3
    echo "Container started. Checking health..."
    for i in {1..20}
    do
        sleep 1
        if get-service-status $image_name $new_slot
        then
            echo "New '$NEW' service seems OK. Switching heads..."
            sleep 2  # Ensure service is ready
            set-active-slot $image_name $new_slot || return 4
            echo "The '$NEW' service is live!"
            sleep 2  # Ensure all requests were processed
            echo "Killing '$OLD'..."
            docker rm -f $OLD
            docker image prune -f
            echo "Deployment successful!"
            return 0
        fi
        echo "New '$NEW' service is not ready yet. Waiting ($i)..."
    done
    echo "New '$NEW' service did not raise, killing it. Failed to deploy T_T"
    docker rm -f $NEW
    return 5
}

ensure-reverse-proxy — , - ( )
get-active-slot service_name — (BLUE GREEN)
get-service-status service_name deployment_slot —
set-active-slot service_name deployment_slot — nginx -

ensure-reverse-proxy() {
    is-container-up reverse-proxy && return 0
    echo "Deploying reverse-proxy..."
    docker network create web-gateway
    docker run \
        --detach \
        --restart always \
        --log-driver journald \
        --name reverse-proxy \
        --network web-gateway \
        --publish 80:80 \
        nginx:alpine || return 1
    docker exec --interactive reverse-proxy sh -c "> /etc/nginx/conf.d/default.conf"
    docker exec reverse-proxy nginx -s reload
}

is-container-up() {
    local container=${1?"Usage: ${FUNCNAME[0]} container_name"}

    [ -n "$(docker ps -f name=${container} -q)" ]
    return $?
}

get-active-slot() {
    local image=${1?"Usage: ${FUNCNAME[0]} image_name"}

    if is-container-up ${image}_BLUE && is-container-up ${image}_GREEN; then
        echo "Collision detected! Stopping ${image}_GREEN..."
        docker rm -f ${image}_GREEN
        return 0  # BLUE
    fi
    if is-container-up ${image}_BLUE && ! is-container-up ${image}_GREEN; then
        return 0  # BLUE
    fi
    if ! is-container-up ${image}_BLUE; then
        return 1  # GREEN
    fi
}

get-service-status() {
    local usage_msg="Usage: ${FUNCNAME[0]} image_name deployment_slot"
    local image=${1?usage_msg}
    local slot=${2?$usage_msg}

    case $image in
        # Add specific healthcheck paths for your services here
        *) local health_check_port_path=":8080/" ;;
    esac
    local health_check_address="http://${image}_${slot}${health_check_port_path}"
    echo "Requesting '$health_check_address' within the 'web-gateway' docker network:"
    docker run --rm --network web-gateway alpine \
        wget --timeout=1 --quiet --server-response $health_check_address
    return $?
}

set-active-slot() {
    local usage_msg="Usage: ${FUNCNAME[0]} service_name deployment_slot"
    local service=${1?$usage_msg}
    local slot=${2?$usage_msg}
    [ "$slot" == BLUE ] || [ "$slot" == GREEN ] || return 1

    get-nginx-config $service $slot | docker exec --interactive reverse-proxy sh -c "cat > /etc/nginx/conf.d/$service.conf"
    docker exec reverse-proxy nginx -t || return 2
    docker exec reverse-proxy nginx -s reload
}

get-active-slot :

, ?

, exit code bash , . , :

get-active-slot service && echo BLUE || echo GREEN.

, ?

, , else.

, nginx: get-nginx-config service_name deployment_slot. , . — cat <<- EOF, . , — , . bash , nginx . , . , , " ", 4 EOF. .

, cat << 'EOF', . cat << EOF, heredoc ( ($foo), ($(bar)) ..), , $ . .

get-nginx-config() {
    local usage_msg="Usage: ${FUNCNAME[0]} image_name deployment_slot"
    local image=${1?$usage_msg}
    local slot=${2?$usage_msg}
    [ "$slot" == BLUE ] || [ "$slot" == GREEN ] || return 1

    local container_name=${image}_${slot}
    case $image in
        # Add specific nginx configs for your services here
        *) nginx-config-simple-service $container_name:8080 ;;
    esac
}

nginx-config-simple-service() {
    local usage_msg="Usage: ${FUNCNAME[0]} proxy_pass"
    local proxy_pass=${1?$usage_msg}

cat << EOF
server {
    listen 80;
    location / {
        proxy_pass http://$proxy_pass;
    }
}
EOF
}

. wget curl.

. localhost :

$ ssh-copy-id localhost
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
himura@localhost's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'localhost'"
and check to make sure that only the key(s) you wanted were added.

, , ? , - ( nginx url ). , ( ), , = .

1: , scp. ssh .

, , .
( ).
.

sed
shh pipe (|)

Truely stateless
No boilerplate entities
Feeling cool

Ansible. , . , . , , :

$ cat << 'EOF' > deploy.sh

#!/bin/bash

usage_msg="Usage: $0 ssh_address local_image_tag"
ssh_address=${1?$usage_msg}
image_name=${2?$usage_msg}

echo "Connecting to '$ssh_address' via ssh to seamlessly deploy '$image_name'..."
( sed "\$a deploy $image_name" | ssh -T $ssh_address ) << 'END_OF_SCRIPT'
deploy() {
    echo "Yay! The '${FUNCNAME[0]}' function is executing on '$(hostname)' with argument '$1'"
}
END_OF_SCRIPT

EOF

$ chmod +x deploy.sh

$ ./deploy.sh localhost magic-porridge-pot
Connecting to 'localhost' via ssh to seamlessly deploy 'magic-pot'...
Yay! The 'deploy' function is executing on 'hut' with argument 'magic-porridge-pot'

, , bash, ( shellbang):

if [ "$SHELL" != "/bin/bash" ]
then
    echo "The '$SHELL' shell is not supported by 'deploy.sh'. Set a '/bin/bash' shell for '$USER@$HOSTNAME'."
    exit 1
fi

$ docker exec reverse-proxy rm /etc/nginx/conf.d/default.conf

$ wget -qO deploy.sh https://git.io/JUc2s

$ chmod +x deploy.sh

$ ./deploy.sh localhost uptimer
Sending gzipped image 'uptimer' to 'localhost' via ssh...
Loaded image: uptimer:latest
Connecting to 'localhost' via ssh to seamlessly deploy 'uptimer'...
Deploying 'uptimer_GREEN' in place of 'uptimer_BLUE'...
06f5bc70e9c4f930e7b1f826ae2ca2f536023cc01e82c2b97b2c84d68048b18a
Container started. Checking health...
Requesting 'http://uptimer_GREEN:8080/' within the 'web-gateway' docker network:
  HTTP/1.0 503 Service Unavailable
wget: server returned error: HTTP/1.0 503 Service Unavailable
New 'uptimer_GREEN' service is not ready yet. Waiting (1)...
Requesting 'http://uptimer_GREEN:8080/' within the 'web-gateway' docker network:
  HTTP/1.0 503 Service Unavailable
wget: server returned error: HTTP/1.0 503 Service Unavailable
New 'uptimer_GREEN' service is not ready yet. Waiting (2)...
Requesting 'http://uptimer_GREEN:8080/' within the 'web-gateway' docker network:
  HTTP/1.0 200 OK
  Server: BaseHTTP/0.6 Python/3.8.3
  Date: Sat, 22 Aug 2020 20:15:50 GMT
  Content-Type: text/html

New 'uptimer_GREEN' service seems OK. Switching heads...
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
2020/08/22 20:15:54 [notice] 97#97: signal process started
The 'uptimer_GREEN' service is live!
Killing 'uptimer_BLUE'...
uptimer_BLUE
Total reclaimed space: 0B
Deployment successful!

http://localhost/ , , .

:3

$ docker rm -f uptimer_GREEN reverse-proxy 
uptimer_GREEN
reverse-proxy

$ docker network rm web-gateway 
web-gateway

$ cd ..

$ rm -r blue-green-deployment

Disclaimer: . , bash-. bash — , , , systemd, systemd /etc/init.d/ . , Docker Swarm Mode (）以及许多功能强大的协调器，其中包含大量现成的无缝布局。但是现成的乐器绝不是万能药。该脚本的诞生不仅是因为对bash脚本的热爱，而且还因为很久以前，在一个遥远的星系中，它比编写一个协调器要容易得多。此外，可以轻松修改它以适合特定应用程序的特定需求。

最低工资的蓝绿色部署

服务

有趣的技术

-

deploy.sh

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`deploy.sh`