Ansible基础一Playbook（二）
摘自：http://www.ansible.com.cn/docs/playbooks_intro.htmlHandlers: 在发生改变时执行的操作
（当发生改动时）’notify’ actions 会在 playbook 的每一个 task 结束时被触发,而且即使有多个不同的 task 通知改动的发生, ‘notify’ actions 只会被触发一次.
举例来说,比如多个 resources 指出因为一个配置文件被改动,所以 apache 需要重新启动,但是重新启动的操作只会被执行一次.
- name: template configuration file
template: src=template.j2 dest=/etc/foo.conf
notify:
- restart memcached
- restart apache
‘notify’ 下列出的即是 handlers.
Handlers 是由通知者进行 notify, 如果没有被 notify,handlers 不会执行.不管有多少个通知者进行了 notify,等到 play 中的所有 task 执行完成之后,handlers 也只会被执行一次.
handlers:
- name: restart memcached
service:name=memcached state=restarted
- name: restart apache
service: name=apache state=restarted
Handlers 最佳的应用场景是用来重启服务,或者触发系统重启操作.
如果你想立即执行所有的 handler 命令,在1.2及以后的版本,你可以这样做:
tasks:
- shell: some tasks go here
- meta: flush_handlers
- shell: some other tasks
在以上的例子中,任何在排队等候的 handlers 会在执行到 ‘meta’ 部分时,优先执行.这个技巧在有些时候也能派上用场.
执行一个playbook
# ansible-playbook -h
Usage: ansible-playbook playbook.yml
Options:
--ask-vault-pass ask for vault password
-C, --check don't make any changes; instead, try to predict some
of the changes that may occur
-D, --diff when changing (small) files and templates, show the
differences in those files; works great with --check
-e EXTRA_VARS, --extra-vars=EXTRA_VARS
set additional variables as key=value or YAML/JSON
--flush-cache clear the fact cache
--force-handlers run handlers even if a task fails
-f FORKS, --forks=FORKS
specify number of parallel processes to use
(default=5)
-h, --help show this help message and exit
-i INVENTORY, --inventory-file=INVENTORY
specify inventory host path
(default=/etc/ansible/hosts) or comma separated host
list.
-l SUBSET, --limit=SUBSET
further limit selected hosts to an additional pattern
--list-hosts outputs a list of matching hosts; does not execute
anything else
--list-tags list all available tags
--list-tasks list all tasks that would be executed
-M MODULE_PATH, --module-path=MODULE_PATH
specify path(s) to module library (default=None)
--new-vault-password-file=NEW_VAULT_PASSWORD_FILE
new vault password file for rekey
--output=OUTPUT_FILEoutput file name for encrypt or decrypt; use - for
stdout
--skip-tags=SKIP_TAGS
only run plays and tasks whose tags do not match these
values
--start-at-task=START_AT_TASK
start the playbook at the task matching this name
--step one-step-at-a-time: confirm each task before running
--syntax-check perform a syntax check on the playbook, but do not
execute it
-t TAGS, --tags=TAGSonly run plays and tasks tagged with these values
--vault-password-file=VAULT_PASSWORD_FILE
vault password file
-v, --verbose verbose mode (-vvv for more, -vvvv to enable
connection debugging)
--version show program's version number and exit
Connection Options:
control as whom and how to connect to hosts
-k, --ask-pass ask for connection password
--private-key=PRIVATE_KEY_FILE, --key-file=PRIVATE_KEY_FILE
use this file to authenticate the connection
-u REMOTE_USER, --user=REMOTE_USER
connect as this user (default=None)
-c CONNECTION, --connection=CONNECTION
connection type to use (default=smart)
-T TIMEOUT, --timeout=TIMEOUT
override the connection timeout in seconds
(default=30)
--ssh-common-args=SSH_COMMON_ARGS
specify common arguments to pass to sftp/scp/ssh (e.g.
ProxyCommand)
--sftp-extra-args=SFTP_EXTRA_ARGS
specify extra arguments to pass to sftp only (e.g. -f,
-l)
--scp-extra-args=SCP_EXTRA_ARGS
specify extra arguments to pass to scp only (e.g. -l)
--ssh-extra-args=SSH_EXTRA_ARGS
specify extra arguments to pass to ssh only (e.g. -R)
Privilege Escalation Options:
control how and which user you become as on target hosts
-s, --sudo run operations with sudo (nopasswd) (deprecated, use
become)
-U SUDO_USER, --sudo-user=SUDO_USER
desired sudo user (default=root) (deprecated, use
become)
-S, --su run operations with su (deprecated, use become)
-R SU_USER, --su-user=SU_USER
run operations with su as this user (default=root)
(deprecated, use become)
-b, --become run operations with become (does not imply password
prompting)
--become-method=BECOME_METHOD
privilege escalation method to use (default=sudo),
valid choices: [ sudo | su | pbrun | pfexec | doas |
dzdo | ksu ]
--become-user=BECOME_USER
run operations as this user (default=root)
--ask-sudo-pass ask for sudo password (deprecated, use become)
--ask-su-pass ask for su password (deprecated, use become)
-K, --ask-become-pass
ask for privilege escalation password
示例：
ansible-playbook playbook.yml -f 10
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