我前面一篇文章讲述了如何这ansible中批量修改主机名，但是上面没有经过严格的测试。

使用hostname模块修改主机名之后，/etc/hosts里的内容是并没有修改的

这里会造成一个问题，如果hosts里的的主机名没有被绑定，那么我们SSH的时候会造成问题，出现主机名无法解析的现象

解决办法。我这里是ubuntu的机器  centos的还没测试过

1. jastme@jastme2:~$ more /etc/nsswitch.conf
   # /etc/nsswitch.conf
   #
   # Example configuration of GNU Name Service Switch functionality.
   # If you have the `glibc-doc-reference' and `info' packages installed, try:
   # `info libc "Name Service Switch"' for information about this file.passwd:         compat
   group:          compat
   shadow:         compat#hosts:          files dns     换成下面的，取消DNS的解析
   hosts:          files
   networks:       filesprotocols:      db files
   services:       db files
   ethers:         db files
   rpc:            db filesnetgroup:       nis

再/etc/ssh/sshd_config中 加入 UseDNS no

以上解决办法可以消除掉hosts文件未被修改而导致ansible运行出错的问题

如何解决这个问题，使用ansible修改主机名，然后再修改hosts文件？

root@ansible:/etc/ansible# pwd
/etc/ansible
root@ansible:/etc/ansible# tree
.
├── ansible.cfg
├── hosts
└── playbooks├── hosts.yml├── script│   └── test.sh├── source├── templates│   ├── hosts.j2│   ├── nrpe.cfg│   ├── nrpe.j2│   ├── profile│   ├── showtime│   └── test.j2└── test.yml4 directories, 11 files
root@ansible:/etc/ansible#

playbook

root@ansible:/etc/ansible# cat playbooks/test.yml
- hosts : testremote_user : jastme
#  gather_facts : nosudo : yestasks:- name : install packetages on ubuntuapt : pkg={{ item }} state=present update_cache=no cache_valid_time=36000 force=yes
#      sudo : yes
#      debug : "{{ item }}"when : ansible_distribution == "Ubuntu"with_items :- gcc- g++- nginx- name : install packetpages on centos
#      yum: name="@Development tools" state=presentyum: name={{ item }} state=presentwhen : ansible_distribution == "RedHat"with_items :- gcc- g++- nginx- name : excute local script on clientscript : script/test.sh                #with local script , same as iterable ===with_lines===- name : change the client hostname by clinet app+ipadd                                                      #在这里我们修改了主机名hostname : name=web{{ ansible_eth1.ipv4.address.split('.')[-1] }}
#      - include : hosts.yml- name : gather facts again                                                                                  #重新获取一次facts,如果不重新获取，hosts.j2文件中的 {{ ansible_hostname }} 变量仍然是修改之前的值setup :- name : change the hosts file because the hosts file not change by ansible hostname module                  #替换文件template : src=templates/hosts.j2 dest=/etc/hosts- name : copy j2 file by template mouldetemplate : src=templates/test.j2 dest=/tmp/test.txt mode=0700notify :- jastme                             # call the handler which name is jastme- name : test the nrpe config file by templattemplate : src=templates/nrpe.j2 dest=/tmp/nrpe.cfgnotify :- restart nrpe- name : copy the nrpe cfg to nrpe dircopy : src=templates/showtime dest=/tmp/showtime    #module copies a file on the local box to remotehandlers:- name : jastmecommand : echo "jastme is here"- name : restart nrpeshell : killall nrpe;/usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -d- name : change the hosts file because the hosts file not change by ansible hostname moduletemplate : src=templates/hosts.j2 dest=/etc/hosts

hosts.j2

root@ansible:/etc/ansible# cat playbooks/templates/hosts.j2
127.0.0.1       localhost {{ ansible_hostname }}

验证

修改之前的

jastme@hello2:~$ cat /etc/hosts
127.0.0.1       localhost hello2
jastme@hello2:~$ cat /etc/hostname
hello2
jastme@hello2:~$ hostname
hello2

测试下结果

root@ansible:/etc/ansible# ansible-playbook playbooks/test.yml -K -vv
sudo password: PLAY [test] ******************************************************************* GATHERING FACTS ***************************************************************
<192.168.1.2> REMOTE_MODULE setup
ok: [192.168.1.2]TASK: [install packetages on ubuntu] ******************************************
<192.168.1.2> REMOTE_MODULE apt pkg=gcc,g++,nginx state=present update_cache=no cache_valid_time=36000 force=yes
ok: [192.168.1.2] => (item=gcc,g++,nginx) => {"changed": false, "item": "gcc,g++,nginx"}TASK: [install packetpages on centos] *****************************************
skipping: [192.168.1.2]TASK: [excute local script on client] *****************************************
changed: [192.168.1.2] => {"changed": true, "rc": 0, "stderr": "", "stdout": "\r\nSUDO-SUCCESS-bcmzwtkepywyexpkhjtrjdvcodebaqer\r\nhello2\r\n"}TASK: [change the client hostname by clinet app+ipadd] ************************
<192.168.1.2> REMOTE_MODULE hostname name=web2
changed: [192.168.1.2] => {"changed": true, "name": "web2"}TASK: [gather facts again] ****************************************************
<192.168.1.2> REMOTE_MODULE setup
ok: [192.168.1.2]TASK: [change the hosts file because the hosts file not change by ansible hostname module] ***
changed: [192.168.1.2] => {"changed": true, "dest": "/etc/hosts", "gid": 0, "group": "root", "md5sum": "91d555f2278a5d5ceef39fd460a03e78", "mode": "0644", "owner": "root", "size": 25, "src": "/home/jastme/.ansible/tmp/ansible-tmp-1458962053.13-120793882613399/source", "state": "file", "uid": 0}TASK: [copy j2 file by template moulde] ***************************************
changed: [192.168.1.2] => {"changed": true, "dest": "/tmp/test.txt", "gid": 1000, "group": "jastme", "md5sum": "a0462664fea4fba50e80f4f863d46f52", "mode": "0700", "owner": "jastme", "size": 16, "src": "/home/jastme/.ansible/tmp/ansible-tmp-1458962053.29-203298900062115/source", "state": "file", "uid": 1000}TASK: [test the nrpe config file by templat] **********************************
ok: [192.168.1.2] => {"changed": false, "gid": 1000, "group": "jastme", "mode": "0600", "owner": "jastme", "path": "/tmp/nrpe.cfg", "size": 1706, "state": "file", "uid": 1000}TASK: [copy the nrpe cfg to nrpe dir] *****************************************
ok: [192.168.1.2] => {"changed": false, "dest": "/tmp/showtime", "gid": 1000, "group": "jastme", "md5sum": "d41d8cd98f00b204e9800998ecf8427e", "mode": "0644", "owner": "jastme", "path": "/tmp/showtime", "size": 0, "state": "file", "uid": 1000}NOTIFIED: [jastme] ************************************************************
<192.168.1.2> REMOTE_MODULE command echo "jastme is here"
changed: [192.168.1.2] => {"changed": true, "cmd": ["echo", "jastme is here"], "delta": "0:00:00.001353", "end": "2016-03-26 11:14:13.754484", "rc": 0, "start": "2016-03-26 11:14:13.753131", "stderr": "", "stdout": "jastme is here"}PLAY RECAP ********************************************************************
192.168.1.2                : ok=10   changed=5    unreachable=0    failed=0

看看客户端的结果

jastme@hello2:~$ cat /etc/hosts
127.0.0.1       localhost web2
jastme@hello2:~$ cat /etc/hostname
web2
jastme@hello2:~$ hostname
web2
jastme@hello2:~$

成功了