这是多余的ansible标签吗？

虽然许多人可能喜欢ansible，但在我看来，它似乎与它有点混淆，有些冗余的概念，如

标签

，

角色

，

目录/主机文件

，

主机组

，

剧本

，

任务

“何时”条件句

要确定最终将执行什么，有相当多的挑战。这个问题的核心问题是

我的理解是，如果我有一个剧本，其中有一个角色包含一个标签列表，那么这些标签将被所有包含的任务添加（继承）

例如：

[----./playbook.yml----]

---
- hosts: all
  roles: 
  - {role: role01, tags: ['tag01', 'tag02']} 
  - {role: role02, tags: ['tag01', 'tag03']}

这意味着在

/roles/role01/tasks/main.yml

中找到的所有任务都将被隐式标记为

tag01

和

tag02

。确认这一点是回答这个问题的一部分

同样地，

/roles/role02/tasks/main.yml

中的所有任务也因此被标记为

tag01

和

tag03

，对吗

现在这里的问题是，查看文件

/roles/role01/tasks/main.yml

我看到了这个内容

[----./roles/role01/tasks/main.yml----]
---
- block:
  - name: "upgrade all packages"
    yum:
      name: '*'
      state: latest
  tags:
    - tag01

考虑到该角色仅从上面所示的

/playbook.yml

行中引用过，我看不出使用

tag01

有什么意义，因为该行应隐式标记该角色：

-{role:role01，标记：['tag01'，'tag02']}

另外，这里还必须使用另一个ansible概念

块

，这让我完全不安

问题的各个方面：

角色的

main.yml

superflous中是否有标记

为什么要使用块（毕竟只有一个任务）

---

TL；Dr：在问题中解释的情况下确实是这样（ansible角色级别的隐式标记使角色内部的单个任务/块标记变得不必要，因此是多余的）

详细信息：

Ansible的语法和风格往往过于复杂和扭曲。在这种情况下，它只是一个不必要的重复标记，加上同样不必要的使用

块

（在ansible playbook中）的语法元素

ansible在标签方面的行为如何得到验证/测试？=>使用shell/bash sctipt：

我已经求助于这个shell脚本，它应该测试ansible

标记

如何与角色的隐式继承相关

bash脚本将创建一个最小的ansible测试用例，它 包含两个角色

role1

和

role2

，均为逐字复制 除了名字（以便能够告诉他们）和 有两项任务：

• 任务（A）

  未明确标记

• task（B）

  是用标签“tag01”明确标记的

还需要一个必要的ansible

playbook.yml

和主机/目录文件

inventory.ini

在脚本中创建：

#!/bin/bash

#make a temporary directory for test
TEMPDIR="$(mktemp -d)"
#change to temporary directory
cd "$TEMPDIR"

# create ansible hosts file "./inventory.ini" 
# only host we need is the the local box (to be simple disregard any ssh overhead)
cat > inventory.ini <<'EOF'
[hosts]
localhost ansible_connection=local
EOF

# create ansilble role "role1"
# (to keep it simple, we have minimal role with only a tasks entry)
mkdir -p roles/role1/tasks
# (the content for the tasks/main.yml file are two tasks, with one task
#  namely task(A) not being explicitly and the task(B) being explicitly
#  tagged)
cat > roles/role1/tasks/main.yml <<'EOF'
---
# tasks file for role1 and role2

- name: "task(A) tagged not explicitly 'tag01'"
  debug:
    msg: "debug-msg: this is \"task(A) tag explicitly 'tag01'\" {{ role_name }} ."

- name: "task(B) tagged explicitly 'tag01'"
  debug:
    msg: "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" {{ role_name }} ."
  tags:
  - tag01
EOF


# create ansible role "role2" as a verbatim copy of "role1"
cp -r roles/role1 roles/role2

# now create an ansible playbook that uses these two ansible roles 
# (note that for the role "role1" we used "implicit tagging"
cat > playbook.yml <<'EOF'
---
- hosts: all
  roles:
  - role: "role1"
    tags: 
    - "tag01"
  - role: "role2"
EOF

# show the test setup 
find . 

# TEST 1:
# run "playbook.yml" one time "as is" ( i.e. no using of tags -> "all tasks"
# should be run)
echo "TEST1" | tee TEST1
ansible-playbook -i inventory.ini playbook.yml | tee -a TEST1

# TEST 2:
# run "playbook.yml" with --tags command line options ( meaning this time
# we limit the task to be run to only those that have the specific tag)
echo "TEST2" | tee TEST2
ansible-playbook -i inventory.ini --tags 'tag01' playbook.yml | tee -a TEST2

# TEST 3:
# run "playbook.yml" with --skip-tags command line options ( meaning this time
# we limit the task to be run all, but those to tags to be "skipped")
echo "TEST3" | tee TEST3
ansible-playbook -i inventory.ini --skip-tags 'tag01' playbook.yml | tee -a TEST3

# show path of temporary directory 
echo "TEMPDIR is $TEMPDIR"

测试2“TEST2”，ansible playbook-i inventory.ini——标记“tag01”playbook.yml：使用标记=>隐式和显式标记事项。自从

tag01

设置为

role1

的

角色级别

包含的任务任务（A）和

任务（B）

都运行。相反，对于

role2

而言，如果没有隐式继承的标记，则只运行

任务（B）

。结果表明：

总之，为了接近问题的主题，角色中包含的任务的a标记是超级的，如果该

角色

已经（a）在

playbook

中标记了自己，从而使其所有任务隐式继承任务，并且b）这是唯一使用的

playbook

角色（就像这里的情况一样）

尽管可以通过执行此处提供的shell脚本生成输出，但出于礼貌和完整性考虑，输出是：

.
./playbook.yml
./roles
./roles/role2
./roles/role2/tasks
./roles/role2/tasks/main.yml
./roles/role1
./roles/role1/tasks
./roles/role1/tasks/main.yml
./inventory.ini
TEST1

PLAY [all] **************************************************************************

TASK [Gathering Facts] **************************************************************************
ok: [localhost]

TASK [role1 : task(A) tagged not explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(A) tag explicitly 'tag01'\" role1 ."
}

TASK [role1 : task(B) tagged explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" role1 ."
}

TASK [role2 : task(A) tagged not explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(A) tag explicitly 'tag01'\" role2 ."
}

TASK [role2 : task(B) tagged explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" role2 ."
}

PLAY RECAP **************************************************************************
localhost                  : ok=5    changed=0    unreachable=0    failed=0   

TEST2

PLAY [all] **************************************************************************

TASK [Gathering Facts] **************************************************************************
ok: [localhost]

TASK [role1 : task(A) tagged not explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(A) tag explicitly 'tag01'\" role1 ."
}

TASK [role1 : task(B) tagged explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" role1 ."
}

TASK [role2 : task(B) tagged explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" role2 ."
}

PLAY RECAP **************************************************************************
localhost                  : ok=4    changed=0    unreachable=0    failed=0   

TEST3

PLAY [all] **************************************************************************

TASK [Gathering Facts] **************************************************************************
ok: [localhost]

TASK [role2 : task(A) tagged not explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(A) tag explicitly 'tag01'\" role2 ."
}

PLAY RECAP **************************************************************************
localhost                  : ok=2    changed=0    unreachable=0    failed=0   

TEMPDIR is /tmp/tmp.cPE6a4gGiG

TEST2 PLAY [all] ************************************************************************** TASK [Gathering Facts] ************************************************************************** ok: [localhost] TASK [role1 : task(A) tagged not explicitly 'tag01'] ************************************************************************** ok: [localhost] => { "msg": "debug-msg: this is \"task(A) tag explicitly 'tag01'\" role1 ." } TASK [role1 : task(B) tagged explicitly 'tag01'] ************************************************************************** ok: [localhost] => { "msg": "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" role1 ." } TASK [role2 : task(B) tagged explicitly 'tag01'] ************************************************************************** ok: [localhost] => { "msg": "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" role2 ." } PLAY RECAP ************************************************************************** localhost : ok=4 changed=0 unreachable=0 failed=0 TEST3 PLAY [all] ************************************************************************** TASK [Gathering Facts] ************************************************************************** ok: [localhost] TASK [role2 : task(A) tagged not explicitly 'tag01'] ************************************************************************** ok: [localhost] => { "msg": "debug-msg: this is \"task(A) tag explicitly 'tag01'\" role2 ." } PLAY RECAP ************************************************************************** localhost : ok=2 changed=0 unreachable=0 failed=0

.
./playbook.yml
./roles
./roles/role2
./roles/role2/tasks
./roles/role2/tasks/main.yml
./roles/role1
./roles/role1/tasks
./roles/role1/tasks/main.yml
./inventory.ini
TEST1

PLAY [all] **************************************************************************

TASK [Gathering Facts] **************************************************************************
ok: [localhost]

TASK [role1 : task(A) tagged not explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(A) tag explicitly 'tag01'\" role1 ."
}

TASK [role1 : task(B) tagged explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" role1 ."
}

TASK [role2 : task(A) tagged not explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(A) tag explicitly 'tag01'\" role2 ."
}

TASK [role2 : task(B) tagged explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" role2 ."
}

PLAY RECAP **************************************************************************
localhost                  : ok=5    changed=0    unreachable=0    failed=0   

TEST2

PLAY [all] **************************************************************************

TASK [Gathering Facts] **************************************************************************
ok: [localhost]

TASK [role1 : task(A) tagged not explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(A) tag explicitly 'tag01'\" role1 ."
}

TASK [role1 : task(B) tagged explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" role1 ."
}

TASK [role2 : task(B) tagged explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(B) tagged explicitly 'tag01'\" role2 ."
}

PLAY RECAP **************************************************************************
localhost                  : ok=4    changed=0    unreachable=0    failed=0   

TEST3

PLAY [all] **************************************************************************

TASK [Gathering Facts] **************************************************************************
ok: [localhost]

TASK [role2 : task(A) tagged not explicitly 'tag01'] **************************************************************************
ok: [localhost] => {
    "msg": "debug-msg: this is \"task(A) tag explicitly 'tag01'\" role2 ."
}

PLAY RECAP **************************************************************************
localhost                  : ok=2    changed=0    unreachable=0    failed=0   

TEMPDIR is /tmp/tmp.cPE6a4gGiG