1. Role introduction
Ansible has introduced new features since version 1.2 for hierarchical and structural organization of playbooks. Roles can automatically load variable files, tasks, and handlers according to the hierarchical structure. To use roles, you only need to use the include directive in the playbook. Simply put, roles are a mechanism by which variables, files, tasks, templates, and processors are placed in separate directories, and they can be included conveniently. Roles are generally used in scenarios where services are built based on the host structure, but they can also be used in scenarios such as building daemons.
Ansible's roles directory structure
project/ 项目名称，有以下子目录
tasks/ 定义task、role的基本元素，至少包含一个名为main.yaml的文件；其他需要的文件在此通过include进行包含
files/ 存放由copy或者script模块调用的文件
vars/ 不常用，定义变量；至少包含一个名为main.yaml的文件；其他需要的文件在此通过include进行包含
default/ 不常用，设定默认变量时使用此目录中的main.yaml
templates/ template模块查找所需要的模板问文件的目录
handlers/
meta/ 不常用，定义当前角色的特殊设定以及依赖关系
2. Case
Deploy nginx on one of the servers, deploy tomcat on the two servers, and use nginx as a reverse proxy to implement polling access to services.
2.1 The total entry file of the role
cat install.yml
- hosts: 10.99.200.110
remote_user: root
gather_facts: false
roles:
- nginx
- hosts: test
remote_user: root
gather_facts: false
roles:
- tomcat
2.2 nginx deployment
step1: define variables
cat vars / main.yml
# defile nginx deploy host ip
nginx_ip: '10.99.200.110'
nginx_port: 10086
nginx_core: 4
nginx_user: 'root'
tomcat_server: 'TMS'
tomcat_server1: '10.99.200.110'
tomcat_server2: '10.99.200.111'
tomcat_port1: 8080
tomcat_port2: 8080
step2: deploy nginx
cat main.yml
- name: unpress nginx
unarchive: src=install_nginx-1.16.1.tar.gz dest=/tmp/
tags:
- unpress
- name: install nginx
shell: cd /tmp/install_nginx-1.16.1 && bash install.sh
- name: replace nginx conf
template: src=nginx.conf.ji2 dest=/usr/local/nginx/conf/nginx.conf
notify:
- reload-nginx
tags:
- reload nginx
- name: start nginx
shell: /etc/init.d/nginx -s reload
step3: nginx configuration file template
cat templates/nginx.conf.ji2
user {
{
nginx_user }};
worker_processes {
{
nginx_core }};
events {
worker_connections 51200;
accept_mutex on;
multi_accept on;
use epoll;
}
http {
include mime.types;
default_type application/octet-stream;
client_max_body_size 500M;
client_header_buffer_size 4k;
server_tokens off;
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /usr/local/nginx/logs/access.log main;
send_timeout 60;
tcp_nodelay on;
underscores_in_headers on;
keepalive_timeout 120;
gzip on;
gzip_min_length 10k;
gzip_buffers 16 64k;
gzip_http_version 1.1;
gzip_comp_level 3;
gzip_types text/plain application/x-javascript text/css application/xml text/javascript application/x-httpd-php application/javascript application/json;
gzip_disable "MSIE [1-6]\.";
gzip_vary on;
proxy_temp_path /usr/local/nginx/ngx_cache 1 2;
proxy_cache_path /usr/local/nginx/ngx_cache/temp levels=1:2 keys_zone=content:1024m inactive=2d max_size=10G;
upstream {
{
tomcat_server }} {
server {
{
tomcat_server1 }}:{
{
tomcat_port1 }};
server {
{
tomcat_server2 }}:{
{
tomcat_port2 }};
}
server {
listen {
{
nginx_port }};
server_name {
{
nginx_ip }};
location / {
root html;
index index.html index.htm;
proxy_pass http://{
{
tomcat_server }};
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
include /usr/local/nginx/conf/conf.d/*.conf;
}
step4: nginx trigger operation
cat handlers/main.yml
- name: reload-nginx
shell: /etc/init.d/nginx -s reload
2.3 tomcat deployment
step1: Define the tomcat installation parameters
cat vars / main.yml
# defile tomcat deploy args
tomcat_path: "/u01/isi/application"
tomcat_version: "apache-tomcat-9.0.33"
step2: deploy tomcat
cat tasks/main.yml
# install tomcat
- name: unpress pacakges
unarchive: src={
{
tomcat_version }}.tar.gz dest={
{
tomcat_path }}
- name: copy scripts for tomcat
copy: src=start.sh dest={
{
tomcat_path }}/{
{
tomcat_version }} mode=0755
- name: copy scripts for tomcat
copy: src=stop.sh dest={
{
tomcat_path }}/{
{
tomcat_version }} mode=0755
- name: start tomcat
shell: cd {
{
tomcat_path }}/{
{
tomcat_version }} && source /etc/profile && ./start.sh
step3: write tomcat startup script
cat files/start.sh
#!/bin/bash
cd /u01/isi/application/apache-tomcat-9.0.33
nohup ./bin/startup.sh &
cat files/stop.sh
#!/bin/bash
ps -ef | grep apache-tomcat-9.0.33 | grep -v grep | awk '{print $2}' | xargs kill -9
2.4 Detect and execute role file
ansible-playbook --check install.yml
ansible-playbook install.yml
2.5 Browser verification
Front-end browser verification 
Back-end log verification
3. File acquisition
链接：https://pan.baidu.com/s/1sHN790EMUISV1P9Okqwa_A
提取码：juey
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