概述
github项目地址： https://github.com/superwujc
尊重原创，欢迎转载，注明出处： https://my.oschina.net/superwjc/blog/3056296
历史系列：
docker CE on Linux示例浅析（一）安装与基本运行
docker CE on Linux示例浅析（二）数据存储与持久化
docker CE on Linux示例浅析（三）镜像与容器管理
docker CE on Linux示例浅析（四）swam群集配置
分布式应用程序的部署需要处理每一个逻辑层以及各层之间的关系，如前端代理，web应用，消息队列，缓存，数据库等。容器化部署为此引入服务编排的概念，用于集中控制容器的生存周期与运行参数，包括但不限于以下方面：
- 容器部署
- 资源控制
- 负载均衡
- 健康检查
- 应用配置
- 规模伸缩
- 位置迁移
docker-ce原生提供了compose与stack两种方式，通过定义在配置文件中的容器运行参数对服务进行编排，配置文件的格式可以为yaml或json。本文以前端代理(nginx) + web程序(tomcat)为例，简述这两种方式的应用。
示例
环境
- 宿主机2台：dock_host_0(192.168.9.168/24)，dock_host_1(192.168.9.169/24)，系统与软件环境一致，均为全新最小化安装，单物理网卡，操作系统版本CentOS Linux release 7.6.1810 (Core)，内核版本3.10.0-957.12.2.el7.x86_64，关闭selinux与防火墙。
- docker为默认安装，版本18.09.6，无其他额外设置。
- 基础镜像为最新版CentOS 7官方镜像。
- tomcat与jdk环境，以及nginx的配置文件与日志，均以目录的方式挂载至容器。
- 源码包jdk-8u212-linux-x64.tar.gz与apache-tomcat-8.5.40.tar.gz，位于宿主机的/opt/目录。
- nginx为tengine，源码编译安装。
compose方式
-
安装docker-compose
https://github.com/docker/compose/releases/ 中包含docker-compose的所有版本，本文以1.24.0为例。
下载源文件：
[root@docker_host_0 ~]# ip addr show eth0 | sed -n '/inet /p' | awk '{print $2}' 192.168.9.168/24 [root@docker_host_0 ~]# [root@docker_host_0 ~]# uname -r 3.10.0-957.12.2.el7.x86_64 [root@docker_host_0 ~]# [root@docker_host_0 ~]# docker -v Docker version 18.09.6, build 481bc77156 [root@docker_host_0 ~]# [root@docker_host_0 ~]# curl -L "https://github.com/docker/compose/releases/download/1.24.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 617 0 617 0 0 540 0 --:--:-- 0:00:01 --:--:-- 541 100 15.4M 100 15.4M 0 0 261k 0 0:01:00 0:01:00 --:--:-- 836k [root@docker_host_0 ~]# [root@docker_host_0 ~]# ll /usr/local/bin/docker-compose -rw-r--r-- 1 root root 16154160 May 30 23:23 /usr/local/bin/docker-compose [root@docker_host_0 ~]# [root@docker_host_0 ~]# chmod u+x /usr/local/bin/docker-compose [root@docker_host_0 ~]# [root@docker_host_0 ~]# which docker-compose /usr/local/bin/docker-compose [root@docker_host_0 ~]# [root@docker_host_0 ~]# docker-compose version docker-compose version 1.24.0, build 0aa59064 docker-py version: 3.7.2 CPython version: 3.6.8 OpenSSL version: OpenSSL 1.1.0j 20 Nov 2018 [root@docker_host_0 ~]#安装命令行补全工具：
[root@docker_host_0 ~]# curl -L https://raw.githubusercontent.com/docker/compose/1.24.0/contrib/completion/bash/docker-compose -o /etc/bash_completion.d/docker-compose % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 13258 100 13258 0 0 14985 0 --:--:-- --:--:-- --:--:-- 14980 [root@docker_host_0 ~]# [root@docker_host_0 ~]# source /etc/bash_completion.d/docker-compose [root@docker_host_0 ~]# [root@docker_host_0 ~]# docker-compose build create exec kill port push run stop up bundle down help logs ps restart scale top version config events images pause pull rm start unpause [root@docker_host_0 ~]# -
部署服务
创建目录挂载的源路径：
本例中，tomcat与jdk分别为/opt/apps/app_0/source与/opt/jdks。
server.xml中的pattern字段用于设置默认的访问日志格式，更改为%A:%{local}p %a:%{remote}p，表示本端IP:端口 对端IP:端口，用于区分访问来源。
[root@docker_host_0 ~]# cd /opt/ [root@docker_host_0 opt]# [root@docker_host_0 opt]# ls apache-tomcat-8.5.40.tar.gz containerd jdk-8u212-linux-x64.tar.gz [root@docker_host_0 opt]# [root@docker_host_0 opt]# mkdir -p /opt/{apps/app_0/source,jdks} [root@docker_host_0 opt]# [root@docker_host_0 opt]# tar axf apache-tomcat-8.5.40.tar.gz --strip-components=1 -C apps/app_0/source/ [root@docker_host_0 opt]# [root@docker_host_0 opt]# sed -i 's/pattern="%h %l %u %t/pattern="%A:%{local}p %a:%{remote}p %t/' apps/app_0/source/conf/server.xml [root@docker_host_0 opt]# [root@docker_host_0 opt]# tar axf jdk-8u212-linux-x64.tar.gz -C jdks/ [root@docker_host_0 opt]#编辑dockerfile：
[root@docker_host_0 opt]# vi dockerfile-for-nginx FROM centos:latest ARG tmp_dir='/tmp' ARG repo_key='http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7' ARG repo_src='http://mirrors.163.com/.help/CentOS7-Base-163.repo' ARG repo_dst='/etc/yum.repos.d/CentOS-Base.repo' ARG tengine_ver='2.3.0' ARG tengine_src="http://tengine.taobao.org/download/tengine-${tengine_ver}.tar.gz" ARG tengine_dst="tengine-${tengine_ver}.tar.gz" ARG tengine_cfg_opts='--prefix=/usr/local/nginx \ --with-http_gzip_static_module \ --with-http_stub_status_module \ --with-http_ssl_module \ --with-http_slice_module \ --with-pcre' ARG depend_rpms='gcc make openssl-devel pcre-devel' RUN cd ${tmp_dir} \ && cp -a ${repo_dst} ${repo_dst}.ori \ && curl -L ${repo_src} -o ${repo_dst} \ && curl -L ${tengine_src} -o ${tengine_dst} \ && rpm --import ${repo_key} \ && yum -y update --downloadonly --downloaddir=. \ && yum -y install ${depend_rpms} --downloadonly --downloaddir=. \ && yum -y install ./*.rpm \ && useradd www -s /sbin/nologin \ && tar axf ${tengine_dst} \ && cd tengine-${tengine_ver} \ && ./configure ${tengine_cfg_opts} \ && make \ && make install \ && cd \ && yum -y remove gcc make cpp \ && yum clean all \ && rm -rf ${tmp_dir}/* EXPOSE 80/tcp 443/tcp ENV PATH ${PATH}:/usr/local/nginx/sbin CMD nginx -g "daemon off;"编辑服务编排配置文件：
docker中的yaml格式配置文件通常以yml或yaml作为后缀（惯例，非强制）。
本例定义了2个服务，名称分别为webapp与proxy：
webapp服务运行centos:latest镜像(image)，挂载数据卷/目录(volumes)，并指定环境变量(environment)，工作目录(working_dir)，容器内运行的命令(command)，以及重启策略(restart)为命令运行失败时(on-failure)。
proxy服务运行tengine_nginx:2.3.0镜像，依赖于webapp服务内的容器启动(depends_on)，并将容器的80端口开放为外部的80端口(ports)。
配置文件内可以通过顶级的networks指令设置网络相关的参数，未指定则按默认设置。对于连接至同一网络驱动下的所有容器，相互之间开放所有端口，本例中，tomcat默认的8080端口对nginx开放，因此端口的对外映射可选(expose/ports)。
[root@docker_host_0 opt]# vi tomcat-with-nginx-compose.yml version: '3.7' services: webapp: image: centos:latest volumes: - /opt/jdks/jdk1.8.0_212:/opt/jdks/jdk1.8.0_212:ro - /opt/apps/app_0/source:/opt/apps/app_0 environment: JAVA_HOME: /opt/jdks/jdk1.8.0_212 working_dir: /opt/apps/app_0 command: bin/catalina.sh run restart: on-failure proxy: build: context: . dockerfile: dockerfile-for-nginx depends_on: - webapp image: tengine_nginx:2.3.0 volumes: - /opt/apps/app_0/nginx/conf:/usr/local/nginx/conf:ro - /opt/apps/app_0/nginx/logs:/usr/local/nginx/logs restart: on-failure ports: - '80:80/tcp'检查编排配置文件：
docker-compose config命令用于检查配置文件的语法与指令，并输出配置文件的所有内容，若指定-q参数则仅执行检查而不输出。
docker-compose默认的配置文件名称为docker-compose.yml或docker-compose.yaml，-f参数用于指定自定义的配置文件。
[root@docker_host_0 opt]# docker-compose -f tomcat-with-nginx-compose.yml config -q [root@docker_host_0 opt]#
编译镜像：
docker-compose build命令根据配置文件中 services.服务名.build 定义的参数编译镜像，若配置文件中未指定build，则不执行该步骤。
[root@docker_host_0 opt]# docker-compose -f tomcat-with-nginx-compose.yml build ... [root@docker_host_0 opt]# [root@docker_host_0 opt]# docker image ls REPOSITORY TAG IMAGE ID CREATED SIZE tengine_nginx 2.3.0 9404e1b71b70 32 seconds ago 340MB centos latest 9f38484d220f 2 months ago 202MB [root@docker_host_0 opt]#
以非守护进程模式(nginx -g "daemon off;")运行nginx 60秒，复制nginx所需文件：
[root@docker_host_0 opt]# docker run -dit --rm --name t_nginx tengine_nginx:2.3.0 bash -c 'timeout 60 nginx -g "daemon off;"' 3cc8de88de3fe295657fde08552165e69514c368689e2078ec89771e23cb16e8 [root@docker_host_0 opt]# [root@docker_host_0 opt]# docker container ls -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 3cc8de88de3f tengine_nginx:2.3.0 "bash -c 'timeout 60…" 7 seconds ago Up 6 seconds 80/tcp, 443/tcp t_nginx [root@docker_host_0 opt]# [root@docker_host_0 opt]# docker exec -it t_nginx ls -l /usr/local/nginx total 0 drwx------ 2 nobody root 6 May 30 23:39 client_body_temp drwxr-xr-x 2 root root 333 May 30 23:37 conf drwx------ 2 nobody root 6 May 30 23:39 fastcgi_temp drwxr-xr-x 2 root root 40 May 30 23:37 html drwxr-xr-x 1 root root 58 May 30 23:39 logs drwx------ 2 nobody root 6 May 30 23:39 proxy_temp drwxr-xr-x 2 root root 19 May 30 23:37 sbin drwx------ 2 nobody root 6 May 30 23:39 scgi_temp drwx------ 2 nobody root 6 May 30 23:39 uwsgi_temp [root@docker_host_0 opt]# [root@docker_host_0 opt]# docker cp t_nginx:/usr/local/nginx/ /opt/apps/app_0/ [root@docker_host_0 opt]# [root@docker_host_0 opt]# ll /opt/apps/app_0/nginx/ total 0 drwx------ 2 root root 6 May 30 23:39 client_body_temp drwxr-xr-x 2 root root 333 May 30 23:37 conf drwx------ 2 root root 6 May 30 23:39 fastcgi_temp drwxr-xr-x 2 root root 40 May 30 23:37 html drwxr-xr-x 2 root root 58 May 30 23:39 logs drwx------ 2 root root 6 May 30 23:39 proxy_temp drwxr-xr-x 2 root root 19 May 30 23:37 sbin drwx------ 2 root root 6 May 30 23:39 scgi_temp drwx------ 2 root root 6 May 30 23:39 uwsgi_temp [root@docker_host_0 opt]#
编辑nginx配置文件：
docker内部实现了服务发现功能，对连接至同一网络驱动下的容器提供名称解析功能，本例中，webapp服务成功启动后，可以被proxy服务的nginx识别。
user www www; worker_processes auto; pid logs/nginx.pid; error_log logs/error.log warn; worker_rlimit_nofile 51200; events { use epoll; worker_connections 4096; } http { include mime.types; default_type application/octet-stream; server_names_hash_bucket_size 128; client_header_buffer_size 16k; large_client_header_buffers 4 32k; client_max_body_size 8m; access_log off; sendfile on; tcp_nopush on; tcp_nodelay on; keepalive_timeout 30; proxy_cache_methods POST GET HEAD; open_file_cache max=655350 inactive=20s; open_file_cache_valid 30s; open_file_cache_min_uses 2; gzip on; gzip_min_length 1k; gzip_buffers 8 8k; gzip_http_version 1.0; gzip_comp_level 4; gzip_types text/plain application/x-javascript text/css application/xml text/javascript application/x-httpd-php; gzip_vary on; server_tokens off; log_format main '$remote_addr\t$upstream_addr\t[$time_local]\t$request\t' '$status\t$body_bytes_sent\t$http_user_agent\t$http_referer\t' '$http_x_forwarded_for\t$request_time\t$upstream_response_time\t$remote_user\t' '$request_body'; map $http_upgrade $connection_upgrade { default upgrade; '' close; } upstream tomcat-app-0 { server webapp:8080; } server { listen 80; server_name 127.0.0.1; charset utf-8; client_max_body_size 75M; location / { proxy_pass http://tomcat-app-0; } access_log logs/webapp-access.log main; } }测试nginx配置文件：
[root@docker_host_0 opt]# docker run -it --rm --mount type=bind,src=/opt/apps/app_0/nginx/conf,dst=/usr/local/nginx/conf,ro --add-host webapp:127.0.0.1 tengine_nginx:2.3.0 bash -c 'nginx -t' nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok nginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful [root@docker_host_0 opt]#
启动服务：
docker-compose up命令用于启动服务：
默认启动配置文件内定义的所有服务，可以显式指定服务名，以启动特定的服务。
若配置文件中指定的镜像名称不存在，则默认首先执行编译(build)。
-d/--detach用于指定容器后台运行，等同于docker run命令的-d/--detach选项。
--scale用于指定相应服务的容器数量，格式为 服务名=数量 。
[root@docker_host_0 opt]# docker-compose -f tomcat-with-nginx-compose.yml up -d --scale webapp=3 Creating network "opt_default" with the default driver Creating opt_webapp_1 ... done Creating opt_webapp_2 ... done Creating opt_webapp_3 ... done Creating opt_proxy_1 ... done [root@docker_host_0 opt]# [root@docker_host_0 opt]# docker container ls -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 6b55fe98a99c tengine_nginx:2.3.0 "/bin/sh -c 'nginx -…" 10 seconds ago Up 9 seconds 0.0.0.0:80->80/tcp, 443/tcp opt_proxy_1 0617d640c60a centos:latest "bin/catalina.sh run" 11 seconds ago Up 9 seconds opt_webapp_2 c85f2de181cd centos:latest "bin/catalina.sh run" 11 seconds ago Up 10 seconds opt_webapp_3 2517e03f11c9 centos:latest "bin/catalina.sh run" 11 seconds ago Up 10 seconds opt_webapp_1 [root@docker_host_0 opt]#
docker-compose默认创建bridge模式的网络：
[root@docker_host_0 opt]# docker network ls NETWORK ID NAME DRIVER SCOPE cb90714e47b3 bridge bridge local a019d8b63640 host host local bb7095896ade none null local 80ce8533b964 opt_default bridge local [root@docker_host_0 opt]#
查看容器内的应用程序运行情况：
docker-compose up可以指定服务名称，以查看特定的服务进程。
[root@docker_host_0 opt]# docker-compose -f tomcat-with-nginx-compose.yml top opt_proxy_1 UID PID PPID C STIME TTY TIME CMD ---------------------------------------------------------------------------------------------- root 13674 13657 0 00:28 ? 00:00:00 nginx: master process nginx -g daemon off; 1000 13738 13674 0 00:28 ? 00:00:00 nginx: worker process 1000 13739 13674 0 00:28 ? 00:00:00 nginx: worker process opt_webapp_1 UID PID PPID C STIME TTY TIME CMD ------------------------------------------------------------------------------------------------- root 13367 13342 1 00:28 ? 00:00:02 /opt/jdks/jdk1.8.0_212/bin/java -Djava.util.l ogging.config.file=/opt/apps/app_0/conf/loggi ng.properties -Djava.util.logging.manager=org .apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.prot ocol.handler.pkgs=org.apache.catalina.webreso urces -Dorg.apache.catalina.security.Security Listener.UMASK=0027 -Dignore.endorsed.dirs= -classpath /opt/apps/app_0/bin/bootstrap.jar: /opt/apps/app_0/bin/tomcat-juli.jar -Dcatalina.base=/opt/apps/app_0 -Dcatalina.home=/opt/apps/app_0 -Djava.io.tmpdir=/opt/apps/app_0/temp org.apache.catalina.startup.Bootstrap start opt_webapp_2 UID PID PPID C STIME TTY TIME CMD ------------------------------------------------------------------------------------------------- root 13436 13388 1 00:28 ? 00:00:02 /opt/jdks/jdk1.8.0_212/bin/java -Djava.util.l ogging.config.file=/opt/apps/app_0/conf/loggi ng.properties -Djava.util.logging.manager=org .apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.prot ocol.handler.pkgs=org.apache.catalina.webreso urces -Dorg.apache.catalina.security.Security Listener.UMASK=0027 -Dignore.endorsed.dirs= -classpath /opt/apps/app_0/bin/bootstrap.jar: /opt/apps/app_0/bin/tomcat-juli.jar -Dcatalina.base=/opt/apps/app_0 -Dcatalina.home=/opt/apps/app_0 -Djava.io.tmpdir=/opt/apps/app_0/temp org.apache.catalina.startup.Bootstrap start opt_webapp_3 UID PID PPID C STIME TTY TIME CMD ------------------------------------------------------------------------------------------------- root 13425 13397 1 00:28 ? 00:00:02 /opt/jdks/jdk1.8.0_212/bin/java -Djava.util.l ogging.config.file=/opt/apps/app_0/conf/loggi ng.properties -Djava.util.logging.manager=org .apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.prot ocol.handler.pkgs=org.apache.catalina.webreso urces -Dorg.apache.catalina.security.Security Listener.UMASK=0027 -Dignore.endorsed.dirs= -classpath /opt/apps/app_0/bin/bootstrap.jar: /opt/apps/app_0/bin/tomcat-juli.jar -Dcatalina.base=/opt/apps/app_0 -Dcatalina.home=/opt/apps/app_0 -Djava.io.tmpdir=/opt/apps/app_0/temp org.apache.catalina.startup.Bootstrap start [root@docker_host_0 opt]#访问web服务，请求被调度至服务内的每个容器：
[root@docker_host_0 opt]# ss -atn | grep 80 LISTEN 0 128 :::80 :::* [root@docker_host_0 opt]# [root@docker_host_0 opt]# for i in $(seq 6); do curl -s 127.0.0.1 -o /dev/null; done [root@docker_host_0 opt]# [root@docker_host_0 opt]# cat /opt/apps/app_0/source/logs/localhost_access_log.$(date +%F).txt 172.20.0.3:80 172.20.0.5:42430 [31/May/2019:00:32:16 +0000] "GET / HTTP/1.0" 200 11184 172.20.0.3:80 172.20.0.5:42436 [31/May/2019:00:32:16 +0000] "GET / HTTP/1.0" 200 11184 172.20.0.4:80 172.20.0.5:45098 [31/May/2019:00:32:16 +0000] "GET / HTTP/1.0" 200 11184 172.20.0.4:80 172.20.0.5:45122 [31/May/2019:00:32:16 +0000] "GET / HTTP/1.0" 200 11184 172.20.0.2:80 172.20.0.5:59294 [31/May/2019:00:32:16 +0000] "GET / HTTP/1.0" 200 11184 172.20.0.2:80 172.20.0.5:59306 [31/May/2019:00:32:16 +0000] "GET / HTTP/1.0" 200 11184 [root@docker_host_0 opt]#
扩充服务内的容器数量：
对同一服务运行docker-compose up命令，--scale用于在现有基础上动态增加或减小容器数量。
[root@docker_host_0 opt]# docker-compose -f tomcat-with-nginx-compose.yml up -d --scale webapp=6 Starting opt_webapp_1 ... done Starting opt_webapp_2 ... done Starting opt_webapp_3 ... done Creating opt_webapp_4 ... done Creating opt_webapp_5 ... done Creating opt_webapp_6 ... done opt_proxy_1 is up-to-date [root@docker_host_0 opt]# [root@docker_host_0 opt]# docker container ls -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES b9fc74985a13 centos:latest "bin/catalina.sh run" 9 seconds ago Up 7 seconds opt_webapp_4 29e9837c7b4d centos:latest "bin/catalina.sh run" 9 seconds ago Up 7 seconds opt_webapp_5 5e0a0611bb2f centos:latest "bin/catalina.sh run" 9 seconds ago Up 8 seconds opt_webapp_6 6b55fe98a99c tengine_nginx:2.3.0 "/bin/sh -c 'nginx -…" 3 minutes ago Up 3 minutes 0.0.0.0:80->80/tcp, 443/tcp opt_proxy_1 0617d640c60a centos:latest "bin/catalina.sh run" 3 minutes ago Up 3 minutes opt_webapp_2 c85f2de181cd centos:latest "bin/catalina.sh run" 3 minutes ago Up 3 minutes opt_webapp_3 2517e03f11c9 centos:latest "bin/catalina.sh run" 3 minutes ago Up 3 minutes opt_webapp_1 [root@docker_host_0 opt]#
移除服务：
docker-compose down命令用于移除服务，包括停止与移除与服务相关联的容器与网络，另可指定--rmi与-v/--volumes选项移除相关联的数据卷与镜像。
[root@docker_host_0 opt]# docker-compose -f tomcat-with-nginx-compose.yml down Stopping opt_webapp_4 ... done Stopping opt_webapp_5 ... done Stopping opt_webapp_6 ... done Stopping opt_proxy_1 ... done Stopping opt_webapp_2 ... done Stopping opt_webapp_3 ... done Stopping opt_webapp_1 ... done Removing opt_webapp_4 ... done Removing opt_webapp_5 ... done Removing opt_webapp_6 ... done Removing opt_proxy_1 ... done Removing opt_webapp_2 ... done Removing opt_webapp_3 ... done Removing opt_webapp_1 ... done Removing network opt_default [root@docker_host_0 opt]# [root@docker_host_0 opt]# docker container ls -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES [root@docker_host_0 opt]# [root@docker_host_0 opt]# [root@docker_host_0 opt]# ss -atn | grep 80 [root@docker_host_0 opt]#
stack方式
宿主机docker_host_0创建群集，docker_host_1以管理角色加入群集：
[root@docker_host_0 opt]# docker swarm init
Swarm initialized: current node (u9siv3gxc4px3xa85t5tybv68) is now a manager.
To add a worker to this swarm, run the following command:
docker swarm join --token SWMTKN-1-5icsimlouv1ppt09fxovvlvn9pp3prevlu2vus6wvtdilv6w86-3y28uwlmc5hcb61hw42oxe4j2 192.168.9.168:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
[root@docker_host_0 opt]#
[root@docker_host_0 opt]# docker swarm join-token manager
To add a manager to this swarm, run the following command:
docker swarm join --token SWMTKN-1-5icsimlouv1ppt09fxovvlvn9pp3prevlu2vus6wvtdilv6w86-elvhukieu148f22dmimq914ki 192.168.9.168:2377
[root@docker_host_0 opt]#
[root@docker_host_1 ~]# ip addr show eth0 | sed -n '/inet /p' | awk '{print $2}'
192.168.9.169/24
[root@docker_host_1 ~]#
[root@docker_host_1 ~]# uname -r
3.10.0-957.12.2.el7.x86_64
[root@docker_host_1 ~]#
[root@docker_host_1 ~]# docker -v
Docker version 18.09.6, build 481bc77156
[root@docker_host_1 ~]#
[root@docker_host_1 ~]# docker swarm join --token SWMTKN-1-5icsimlouv1ppt09fxovvlvn9pp3prevlu2vus6wvtdilv6w86-elvhukieu148f22dmimq914ki 192.168.9.168:2377
This node joined a swarm as a manager.
[root@docker_host_1 ~]#
[root@docker_host_1 ~]# docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION
u9siv3gxc4px3xa85t5tybv68 docker_host_0 Ready Active Leader 18.09.6
qhgpqw9n5wwow1zfzji69eac0 * docker_host_1 Ready Active Reachable 18.09.6
[root@docker_host_1 ~]#
在docker_host_0节点上导出tengine_nginx:2.3.0镜像，并传输至docker_host_1节点：
[root@docker_host_0 opt]# docker image ls REPOSITORY TAG IMAGE ID CREATED SIZE tengine_nginx 2.3.0 9404e1b71b70 About an hour ago 340MB centos latest 9f38484d220f 2 months ago 202MB [root@docker_host_0 opt]# [root@docker_host_0 opt]# docker image save tengine_nginx:2.3.0 -o nginx.tar [root@docker_host_0 opt]# [root@docker_host_0 opt]# ll -h nginx.tar -rw------- 1 root root 338M May 31 00:56 nginx.tar [root@docker_host_0 opt]# [root@docker_host_0 opt]# scp -P 9999 nginx.tar root@192.168.9.169:/opt nginx.tar 100% 337MB 83.1MB/s 00:04 [root@docker_host_0 opt]#
在docker_host_1节点上导入tengine_nginx:2.3.0镜像，并设置与docker_host_0节点相同的挂载源路径：
[root@docker_host_1 ~]# cd /opt/
[root@docker_host_1 opt]#
[root@docker_host_1 opt]# ls
apache-tomcat-8.5.40.tar.gz containerd jdk-8u212-linux-x64.tar.gz nginx.tar
[root@docker_host_1 opt]#
[root@docker_host_1 opt]# docker image load -i nginx.tar
d69483a6face: Loading layer 209.5MB/209.5MB
717661697400: Loading layer 144.3MB/144.3MB
Loaded image: tengine_nginx:2.3.0
[root@docker_host_1 opt]#
[root@docker_host_1 opt]# docker image ls -a
REPOSITORY TAG IMAGE ID CREATED SIZE
tengine_nginx 2.3.0 9404e1b71b70 About an hour ago 340MB
[root@docker_host_1 opt]#
[root@docker_host_1 opt]# mkdir -p /opt/{apps/app_0/source,jdks}
[root@docker_host_1 opt]#
[root@docker_host_1 opt]# tar axf apache-tomcat-8.5.40.tar.gz --strip-components=1 -C apps/app_0/source/
[root@docker_host_1 opt]#
[root@docker_host_1 opt]# sed -i 's/pattern="%h %l %u %t/pattern="%A:%{local}p %a:%{remote}p %t/' apps/app_0/source/conf/server.xml
[root@docker_host_1 opt]#
[root@docker_host_1 opt]# tar axf jdk-8u212-linux-x64.tar.gz -C jdks/
[root@docker_host_1 opt]#
在docker_host_0节点上编辑服务编排配置文件：
volumes与port是使用长格式指定挂载点与端口。
services.服务名.deploy 指定服务的运行模式(mode)，副本数量(replicas)，重启策略(restart_policy)，服务所在节点(placement)。
[root@docker_host_0 opt]# vi tomcat-with-nginx-stack.yml
version: "3.7"
services:
webapp:
image: centos:latest
volumes:
- type: bind
source: /opt/jdks/jdk1.8.0_212
target: /opt/jdks/jdk1.8.0_212
read_only: true
- type: bind
source: /opt/apps/app_0/source
target: /opt/apps/app_0
environment:
JAVA_HOME: /opt/jdks/jdk1.8.0_212
working_dir: /opt/apps/app_0
command: bin/catalina.sh run
deploy:
mode: replicated
replicas: 3
restart_policy:
condition: on-failure
proxy:
image: tengine_nginx:2.3.0
volumes:
- type: bind
source: /opt/apps/app_0/nginx/conf
target: /usr/local/nginx/conf
read_only: true
- type: bind
source: /opt/apps/app_0/nginx/logs
target: /usr/local/nginx/logs
deploy:
placement:
constraints:
- node.hostname == docker_host_0
mode: global
restart_policy:
condition: on-failure
ports:
- target: 80
published: 80
protocol: tcp
mode: ingress
部署服务，名称为web-cluster：
[root@docker_host_0 opt]# docker stack deploy -c tomcat-with-nginx-stack.yml web-cluster Creating network web-cluster_default Creating service web-cluster_proxy Creating service web-cluster_webapp [root@docker_host_0 opt]#
副本服务webapp被分配至2个节点，全局服务proxy按约束条件(constraints)被分配至docker_host_0节点：
[root@docker_host_0 opt]# docker service ls ID NAME MODE REPLICAS IMAGE PORTS onshpipwwcmd web-cluster_proxy global 1/1 tengine_nginx:2.3.0 *:80->80/tcp pvj1cyvutjc5 web-cluster_webapp replicated 3/3 centos:latest [root@docker_host_0 opt]# [root@docker_host_0 opt]# docker service ps web-cluster_webapp ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS rp9xuqzbns3p web-cluster_webapp.1 centos:latest docker_host_1 Running Running 12 seconds ago 479ea4e8q8k1 web-cluster_webapp.2 centos:latest docker_host_1 Running Running 12 seconds ago nlr7lc6g7m4v web-cluster_webapp.3 centos:latest docker_host_0 Running Running 13 seconds ago [root@docker_host_0 opt]# [root@docker_host_0 opt]# docker service ps web-cluster_proxy ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS ma8wr6kn8vyf web-cluster_proxy.u9siv3gxc4px3xa85t5tybv68 tengine_nginx:2.3.0 docker_host_0 Running Running 10 seconds ago j6w9au6v8tzt \_ web-cluster_proxy.u9siv3gxc4px3xa85t5tybv68 tengine_nginx:2.3.0 docker_host_0 Shutdown Failed 15 seconds ago "task: non-zero exit (1)" [root@docker_host_0 opt]#
stack默认使用swarm模式初始创建的overlay网络：
[root@docker_host_0 opt]# docker network ls NETWORK ID NAME DRIVER SCOPE cb90714e47b3 bridge bridge local dfe3ba6e0df5 docker_gwbridge bridge local a019d8b63640 host host local mxcmpb9uzjy2 ingress overlay swarm bb7095896ade none null local qn3rp2t93lli web-cluster_default overlay swarm [root@docker_host_0 opt]#
通过docker_host_0与docker_host_1节点均可访问被代理的web服务：
[root@docker_host_1 opt]# ss -atn | grep 80 LISTEN 0 128 :::80 :::*
[root@docker_host_0 opt]# ss -atn | grep 80
LISTEN 0 128 :::80 :::*
[root@docker_host_0 opt]#
[root@docker_host_0 opt]# curl -I -o /dev/null -s -w %{http_code} 127.0.0.1
200
[root@docker_host_0 opt]# curl -I -o /dev/null -s -w %{http_code} 192.168.9.168
200
root@docker_host_0 opt]# curl -I -o /dev/null -s -w %{http_code} 192.168.9.169
200
[root@docker_host_0 opt]#
depends_on指令用于指定镜像的构建顺序，以及容器的启动与停止顺序，若需要解决容器内应用程序间的依赖关系，则需手动实现容器内命令的慢启动，或借助于诸如 dockerize 之类的第三方工具。
区别与联系
stack与compose均通过yaml或json格式的配置文件进行服务的编排，区别主要包括：
- 某些指令在两种方式下不兼容，如build，deploy，depends_on，restart_policy等。
- stack由 docker 引擎内置，须开启swarm模式，组成同一服务的多个容器可能跨越多个宿主机，因此要求相应的镜像必须存在于宿主机本地或可访问的仓库中；compose需要额外安装，无须开启swarm模式，所有容器均位于当前单个宿主机。
- stack仅可根据预先已编译的镜像部署服务；compose支持镜像的编译与服务的部署，二者可同时执行，或单独执行。
参考
以上所述就是小编给大家介绍的《docker CE on Linux示例浅析（五）服务编排 原 荐》，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对 码农网 的支持！
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