Syntax Error while loading YAML

问题:

I do have a role foo defined this way:

# roles/foo/tasks/main.yml
---
- name: restart Apache
    systemd:
      name: apache2
      state: restarted
      daemon_reload: yes

bute when I start the playbook which requests this role then I get this error:

ERROR! Syntax Error while loading YAML.


The error appears to have been in '/root/roles/foo/tasks/main.yml': line 4, column 12, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

- name: restart Apache
    systemd:
           ^ here

I do not understand what is wrong here because I found such samples in the documentation...
(I left out the other parts which are defined in this role and are working well)

回答1:

Fix indentation:

---
- name: restart Apache
  systemd:
    name: apache2
    state: restarted
    daemon_reload: yes

I do not understand what is wrong here because I found such samples in the documentation...

Indentation in YAML is significant for interpretation. Certain elements must be defined at the same level.

Notice that systemd: line ends with a colon and is followed by an indented block (where the whole block becomes its value), while name: has value restart Apache defined in the same line.