Asible Learning Notes--Common Modules

Posted by jharbin on Sun, 17 Nov 2019 05:15:50 +0100

Ansible Common Modules

Modules included in this section:

(1) Timing task module cronvar

(2) archive module

(3) Unpacking module unarchive

(4) Download module get_url

(5) wait_for module

(6) script module

Timed Task Module cronvar

In addition to the cron module itself, which can manage cron's environment variables, another module, cronvar, can also define environment variables for timed tasks.

cronvar--Ansible official usage documentation

ansible-doc -s cronvar
- name: Manage variables in crontabs
      backup:     # (yes/no) If set, these files will be backed up before modifying the remote cron_file
      cron_file:  # Customize the filename of cron_file, using relative paths to represent in/etc/cron.d
      state:      # Presents create variables, absent s remove variables
      user:       # Specifies which user's crontab will be modified, defaulting to root
      value:      # The value of the environment variable, requiring state=present

(1) For example, create a job, synchronize every 2 minutes, and customize cron_file.

ansible test -m cron -a 'name="ntpdate" job="/usr/sbin/ntpdate" cron_file=ntpdate_cron user=root minute=*/2' -o -f 8

Verify that you added it correctly.

ansible test -m shell -a 'cat /etc/cron.d/ntpdate_cron' | CHANGED | rc=0 >>
#Ansible: ntpdate
*/2 * * * * root /usr/sbin/ntpdate

(2) Remove a job, requiring the name to match.If necessary, both cron_file and user need to be specified.

Ansible Test-M cron-a'name="ntpdate" state=absent cron_file=ntpdate_cron user=root'-o #/etc/cron.d/ntpdate_cron This file still exists (empty content)

archive module

Used to compress files remotely.Of course, the precondition is to have a corresponding compression tool on the remote host.Supports zip/gz/tar/bz2.

Archve--Ansible official usage documentation

ansible-doc -s archive
- name: Creates a compressed archive of one or more files or trees
      dest:   # Target archive file name.The dest option is required unless path specifies that a single file is to be compressed
      format: # Specify compression format, default to gz format
      group:  # The group to which the file/directory belongs
      owner:  # Owner of file/directory
      mode:   # Set file/directory permissions to support formats such as'0644'o r'u+rwx' o r'u=rw,g=r,o=r'
      path:   # The file to be compressed can be an absolute path, a glob-specific path, or a list of files
      remove: # Delete source files after compression

Examples are as follows:

(1) Compress the file into the default gz format. Since path specifies that the file is to be compressed as a single file, dest is not used:

ansible test -m archive -a 'path="/tmp/mu.txt"'

Description: GZ suffix compression package decompression command: gzip-d mu.txt.gz

(2) Compress directory/path/to/foo/to/path/to/foo.tgz:

ansible test -m archive -a 'path="/tmp/xyz" dest=/tmp/xyz.tgz'

(3) Compress single file/path/to/foo into zip format:

ansible test -m archive -a 'path="/tmp/mu.txt" format=zip'

Description: Decompression command for zip suffix compression package: unzip

(4) Compress the given list of files into bz2 format with a compressed package path of/path/file.tar.bz2:

- name: Create a bz2 archive of multiple files, rooted at /path
    - /path/to/foo
    - /path/wong/foo
    dest: /path/file.tar.bz2
    format: bz2

Unpack module unarchive

By default, the archive files on the ansible side are copied to the controlled host and unpacked on the controlled host.If the option remote_src=yes is set, it means unpacking the archive files on the controlled host.

Requires corresponding unpacking commands on the controlled host.The unzip command is used to unzip the'.zip'file, and the gtar (provided by the tar package) command is used to unzip'.tar','.tar.gz',' 2' and'.tar.xz'.

unarchive--Ansible official usage documentation

ansible-doc -s unarchive
- name: Unpacks an archive after (optionally) copying it from the local machine.
      creates:         # Do not perform the task if the specified file exists.Can be used to achieve idempotency
      dest:            # An archive file on a remote machine that needs to be unpacked, requiring an absolute path
      exclude:         # List directories and files that you want to ignore during unpacking
      group:           # The group to which the file/directory belongs
      owner:           # Owner of file/directory
      mode:            # Set file/directory permissions to support formats such as'0644'o r'u+rwx' o r'u=rw,g=r,o=r'
      keep_newer:      # During unpacking, if a file with the same name exists in the destination path and in the package and is newer than the file in the package, the new file is retained
      list_files:      # When set to true, a list of files in the archive file is returned
      remote_src:      # Setting to yes indicates that the target archive file already exists on the remote host, that is, the archive file is no longer copied locally to the remote end and is unpacked directly at the remote end.
                       # Default to no
      src:             # If remote_src=no, the local archive file will be copied to the remote, either relative or absolute.
                       # If remote_src=yes, the remote existing archive file will be unpacked
                       # If remote_src=yes and Src contains'://', command the remote host to download and unpack files from the url

Download module get_url

get_url--Ansible official usage documentation

ansible-doc -s get_url
- name: Downloads files from HTTP, HTTPS, or FTP to node
      backup:     # Create a backup file with a time stamp in the name when downloading the file
      dest:       # File save path, must be absolute path.
                  # If dest is a directory, use base name of url as file name
                  # The'force'option does not work if dest is a directory
                  # If dest is a directory, the target file will always be downloaded, but the old file will only be replaced if the existing file changes
      force:      # If set to yes and dest is not a directory, files are always downloaded, but old files are replaced only if existing files have changed
                  # If set to no (default), the file will only be downloaded if it does not exist in the directory path.
      tmp_dest:   # Temporarily store directory during download and delete downloaded temporary files before task execution is complete
      group:      # The group to which the file/directory belongs
      owner:      # Owner of file/directory
      mode:       # Set file/directory permissions to support formats such as'0644'o r'u+rwx' o r'u=rw,g=r,o=r'
      timeout:    # Timeout when url is requested, default 10 seconds
      url:        # url path to download, (http|https|ftp): //[user[:pass]@host.domain[:port]/path
                  # Paths in file format are also supported for replication.file:///path/to/file

Note that when dest is a directory or force=yes, files are always downloaded to a temporary storage directory, but the old files are not necessarily replaced.Only if force=no (default) and dest is a file, the file will not be downloaded if it already exists.

Examples are as follows:

(1) Download foo.conf, if / etc/foo.conf already exists, do not download it:

- name: Download foo.conf
    dest: /etc/foo.conf
    mode: '0440'

wait_for module

Sometimes tasks depend on resources such as status, files, ports, etc. The task will continue only if the prerequisite is met.The wait_for module is used to determine what conditions a task will continue to meet.Mainly used to determine whether the port is open, whether the file exists, whether there are some strings in the file.

wait_for--Ansible official usage documentation

ansible-doc -s wait_for
- name: Waits for a condition before continuing
      delay:          # Number of seconds to wait before the check operation takes place
      host:           # Wait for this host to be started, defaulting to
      port:           # Wait for this port to open
      path:           # Does this file already exist
      search_regex:   # Regular Matching in Files
      state:          # Present/start/stop/absent/drained.Default start
                      # When checking a port:
                      # Start: Make sure the port is open
                      # stopped: Make sure the port is closed
                      # When checking a file:
                      # Present/start: Continue after checking that the file exists
                      # absent: Check to continue until the file is removed
      sleep:          # Seconds of sleep between checks, default 1 second
      timeout:        # Check wait timeout (seconds, default 300)

Examples are as follows:

(1) Check if port 8000 is open 10 seconds after connecting to the host, or time out if port 8000 is not open within 300 seconds (default).

- name: Wait for port 8000 to become open on the host, don't start checking for 10 seconds
    port: 8000
    delay: 10

(2) Do not continue until / tmp/foo file exists

- name: Wait until the file /tmp/foo is present before continuing
    path: /tmp/foo

(3) Do not continue until a "completed" string can be matched in the /tmp/foo file

- name: Wait until the string "completed" is in the file /tmp/foo before continuing
    path: /tmp/foo
    search_regex: completed

(4) Continue until the lock file / var/lock/file.lock is removed

- name: Wait until the lock file is removed
    path: /var/lock/file.lock
    state: absent

(5) Continue until the / proc/3466/status file is removed to determine whether the process is started or stopped, whether the pid file exists or is removed, etc.

- name: Wait until the process is finished and pid was destroyed
    path: /proc/3466/status
    state: absent

script module

The script module is used to control the remote host to execute scripts.Before executing the script, ansible transfers the local script to the remote host and executes it.When executing the script, it uses the shell environment on the remote host.

script--Ansible official usage documentation

ansible-doc -s script
- name: Runs a local script on a remote node after transferring it
      chdir:       # Switch to this directory before remotely executing the script.
      creates:     # When this file exists, the script is not executed.It can be used to realize idempotency.
      removes:     # Do not execute scripts when this file does not exist.It can be used to realize idempotency.
      free_form:   # Local script path, options, parameters to execute.free_form is called because it is a script name + option + parameter.


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Topics: Linux ansible shell ftp crontab