Clever Geek Handbook

Mengurai Ansible Loops

Posting ini mencakup modul loop yang mungkin berikut: with_items, with_nested, with_subelements, with_dict.



Semua ini dengan * sudah tidak digunakan lagi dan direkomendasikan untuk menggunakan loop.



Sumber



Salah satu peran saya di Chromatic adalah sebagai anggota tim DevOps. Antara lain, ini termasuk bekerja dengan server kami dan server klien kami. Ini, pada gilirannya, berarti saya menghabiskan banyak waktu bekerja dengan Ansible , alat populer untuk menyediakan, mengonfigurasi, dan menerapkan server dan aplikasi.



Sederhananya, mesin yang menjalankan Ansible menjalankan perintah di komputer lain melalui SSH. Perintah ini ditetapkan secara deklaratif (opsional) menggunakan bagian kecil YAML yang disebut tugas. TASKS ini memanggil modul Ansible yang berspesialisasi dalam menjalankan opsi pada komponen tertentu seperti file, database, dll.



Misalnya, tugas berikut menggunakan modul File ( dokumentasi , kode ) untuk membuat direktori tertentu jika belum ada, dan mengubah atributnya jika belum disetel dengan benar:



- file:
    path: /home/jenkins/.ssh
    state: directory
    owner: jenkins
    group: jenkins
    mode: 700


Beberapa tugas yang terkait dengan satu tugas dikelompokkan menjadi beberapa peran, dan beberapa peran dapat dikelompokkan ke dalam buku pedoman. Anda kemudian dapat menggunakan pedoman tersebut untuk melakukan langkah-langkah konfigurasi yang persis sama pada sejumlah server pada waktu yang sama.



Apakah Ansible declarative?



TASKS Ansible , , TASKS. , , , . , Ansible Copy, . Ansible , :



- name: Copy SSH config file into Alice’s .ssh directory.
  copy:
    src: files/config
    dest: /home/alice/.ssh/config
    owner: alice
    group: alice
    mode: 0600


, , bash, scp, chown chmod. Ansible , .



, , — , , .



, Ansible, — TASKS . , Ansible , , — PHP, .



, Ansible. Loops , «loops _ + lookup(), ». (Lookups) — Ansible, « Ansible », Loops Ansible Github, .



Ansible « », , . Ansible, , , .



Ansible



TASKS, , , , , ( : , , , , !)



:



  1. , : alice, bob, carol dan.



  2. , : .ssh/ loops.



  3. , . , alice :





/home/alice/
├── .ssh/
├── bob/
├── carol/
├── dan/
└── loops/


1. WITH_ITEMS



Ansible , chuck , :



- name: Remove user ‘Chuck’ from the system.
  user:
    name: chuck
    state: absent
    remove: yes


— , Chuck Craig — with_items. with_items ( ), ( ):



- name: Remove users ‘Chuck’ and ‘Craig’ from the system.
  user:
    name: "{{ item }}"
    state: absent
    remove: yes
  with_items:
    - chuck
    - craig


, with_items , alice bob:





users_with_items:
  - name: "alice"
    personal_directories:
      - "bob"
      - "carol"
      - "dan"
  - name: "bob"
    personal_directories:
      - "alice"
      - "carol"
      - "dan"


TASKS


- name: "Loop 1: create users using 'with_items'."
  user:
    name: "{{ item.name }}"
  with_items: "{{ users_with_items }}"


Ansible User users_with_items. , , , , personal_directories ( , personal_directories — ).



Ansible ( Ansible ): TASKS , . , , personal_directories TASKS (. . User, File).



with_items , PHP:



<?php

foreach ($users_with_items as $user) {
  // Do something with $user...
}


, , :



• item.name .



• with_items, .



, Ansible item, item.property.





/home/
├── alice/
└── bob/


2: , WITH_NESTED



: 2 , 1. chown failed: failed to look up user



, users_with_items 1, , common_directories, , . , ( PHP), -, :



<?php

foreach ($users_with_items as $user) {
  foreach ($common_directories as $directory) {
    // Create $directory for $user...
  }
}


Ansible with_nested. with_nested , :





users_with_items:
  - name: "alice"
    personal_directories:
      - "bob"
      - "carol"
      - "dan"
  - name: "bob"
    personal_directories:
      - "alice"
      - "carol"
      - "dan"

common_directories:
  - ".ssh"
  - "loops


TASKS


# Note that this does not set correct permissions on /home/{{ item.x.name }}/.ssh!
- name: "Loop 2: create common users' directories using 'with_nested'."
  file:
    dest: "/home/{{ item.0.name }}/{{ item.1 }}"
    owner: "{{ item.0.name }}"
    group: "{{ item.0.name }}"
    state: directory
  with_nested:
    - "{{ users_with_items }}"
    - "{{ common_directories }}"


, with_nested , item.0 ( users_with_items) item.1 ( common_directories) . , , /home/alice/.ssh .





/home/
├── alice/
│   ├── .ssh/
│   └── loops/
└── bob/
    ├── .ssh/
    └── loops/


3: , WITH_SUBELEMENTS



: 3 , 1. chown failed: failed to look up user



with_subelements , users_with_items 1. PHP :



<?php

foreach ($users_with_items as $user) {
  foreach ($user['personal_directories'] as $directory) {
    // Create $directory for $user...
  }
}


, $users_with_items $user['personal_directories'] .





users_with_items:
  - name: "alice"
    personal_directories:
      - "bob"
      - "carol"
      - "dan"
  - name: "bob"
    personal_directories:
      - "alice"
      - "carol"
      - "dan"


TASKS


- name: "Loop 3: create personal users' directories using 'with_subelements'."
  file:
    dest: "/home/{{ item.0.name }}/{{ item.1 }}"
    owner: "{{ item.0.name }}"
    group: "{{ item.0.name }}"
    state: directory
  with_subelements:
    - "{{ users_with_items }}"
    - personal_directories


with_subelements , with_nested, , , — personal_directories. 2, ( ) /home/alice/bob.





/home/
├── alice/
│   ├── .ssh/
│   ├── bob/
│   ├── carol/
│   ├── dan/
│   └── loops/
└── bob/
    ├── .ssh/
    ├── alice/
    ├── carol/
    ├── dan/
    └── loops/


4: WITH_DICT



3 , alice bob, , , carol dan. users_with_dict Ansible with_dict.



, (dict dictionary — Python ); with_dict , . , Ansible, PHP :



<?php

foreach ($users_with_dict as $user => $properties) {
  // Create a user named $user...
}




users_with_dict:
  carol:
    common_directories: "{{ common_directories }}"
  dan:
    common_directories: "{{ common_directories }}"


TASKS


- name: "Loop 4: create users using 'with_dict'."
  user:
    name: "{{ item.key }}"
  with_dict: "{{ users_with_dict }}"


with_dict . , , , dict with_dict (, , with_dict ).





/home/
├── alice/
│   ├── .ssh/
│   ├── bob/
│   ├── carol/
│   ├── dan/
│   └── loops/
├── bob/
│   ├── .ssh/
│   ├── alice/
│   ├── carol/
│   ├── dan/
│   └── loops/
├── carol/
└── dan/


5: ,



users_with_dict, Ansible, -. alice, bob, carol dan, with_nested /home/. , , , TASKS:



  • Ansible

    • Ansible
    • Jinja2 ()
    • Jinja2 ()




common_directories:
  - ".ssh"
  - "loops"


TASKS


- name: "Get list of extant users."
  shell: "find * -type d -prune | sort"
  args:
    chdir: "/home"
  register: "home_directories"
  changed_when: false

- name: "Loop 5: create personal user directories if they don't exist."
  file:
    dest: "/home/{{ item.0 }}/{{ item.1 }}"
    owner: "{{ item.0 }}"
    group: "{{ item.0 }}"
    state: directory
  with_nested:
    - "{{ home_directories.stdout_lines }}"
    - "{{ home_directories.stdout_lines | union(common_directories) }}"
  when: "'{{ item.0 }}' != '{{ item.1 }}'"


TASKS: shell find , file .



/home find \ -type d -prune | sort ( shell) , /home, , , .



home_directories register: "home_directories" . , , :



"stdout_lines": [
  "alice",
  "bob",
  "carol",
  "dan",
],


( ) with_nested , :



  1. with_nested :


- "{{ home_directories.stdout_lines | union(common_directories) }}"


  1. , when TASKS:



    when: "'{{ item.0 }}' != '{{ item.1 }}'"




. with_nested Jinja2 TASKS ( home_directories.stdout_lines). Jinja:



  • (home_directories.stdout_lines)
  • (|)
  • , (union (common_directories))


, home_directories.stdout_lines common_directories :



item:
  - .ssh
  - alice
  - bob
  - carol
  - dan
  - loops


, with_nested home_directories.stdout_lines ( with_nested) , .



, — , , , ! (, /home/alice/alice, /home/bob/bob . .) Ansible — when — :



when: "'{{ item.0 }}' != '{{ item.1 }}'"


, home_directories.stdout_lines home_directories.stdout_lines ( Ansible Loops, «… when with_items ( ), when »). PHP , , :



<?php

$users = ['alice', 'bob', 'carol', 'dan'];
$common_directories = ['.ssh', 'loops'];
$directories = $user + $common_directories;

foreach ($users as $user) {
  foreach ($directories as $directory) {
    if ($directory != $user) {
      // Create the directory…
    }
  }
}


, , .





/home/
├── alice/
│   ├── .ssh/
│   ├── bob/
│   ├── carol/
│   ├── dan/
│   └── loops/
├── bob/
│   ├── .ssh/
│   ├── alice/
│   ├── carol/
│   ├── dan/
│   └── loops/
├── carol/
│   ├── .ssh/
│   ├── alice/
│   ├── bob/
│   ├── dan/
│   └── loops/
└── dan/
    ├── .ssh/
    ├── alice/
    ├── bob/
    ├── carol/
    └── loops/




Ansible . ( Ansible), , (with_nested? with_subitems?) .



, , TASKS, ( , array_filter, array_reduce, array_map , ). , , — — .



Semoga posting ini akan membantu Anda menyingkirkan kesulitan awal saya. Untuk tujuan ini, saya membuat mesin virtual Vagrant (Vagrant secara native mendukung menggunakan Ansible untuk penyediaan) dan buku pedoman Ansible yang saya gunakan untuk membuat dan menguji contoh-contoh ini). Cukup ikuti petunjuk di README untuk menjalankan contoh dari posting ini atau coba sendiri. Jika Anda memiliki pertanyaan atau komentar, silakan tweet di @chromaticHQ!



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