diff --git a/knowledge base/acronyms and abbreviations.md b/knowledge base/acronyms and abbreviations.md
index 76543de..99bd7f2 100644
--- a/knowledge base/acronyms and abbreviations.md	
+++ b/knowledge base/acronyms and abbreviations.md	
@@ -22,6 +22,7 @@
 | BYOD    | Bring Your Own Device                                  |                                                                                                     |
 | CD      | Continuous Delivery                                    | Continuous creation and testing of artifacts, ready to be deployed at the end of the process        |
 | CD      | Continuous Deployment                                  |                                                                                                     |
+| CDN     | Content Delivery Network                               |                                                                                                     |
 | CI      | Continuous Integration                                 |                                                                                                     |
 | CLI     | Command Line Interface                                 |                                                                                                     |
 | CMS     | Content Management System                              |                                                                                                     |
diff --git a/knowledge base/ansible.md b/knowledge base/ansible.md
index 088e898..cfaac8f 100644
--- a/knowledge base/ansible.md	
+++ b/knowledge base/ansible.md	
@@ -13,6 +13,7 @@
 1. [Error handling](#error-handling)
    1. [Using blocks](#using-blocks)
 1. [Output formatting](#output-formatting)
+1. [Handlers](#handlers)
 1. [Roles](#roles)
    1. [Get roles](#get-roles)
    1. [Assign roles](#assign-roles)
@@ -504,6 +505,46 @@ $ ANSIBLE_STDOUT_CALLBACK='json' ansible-playbook --inventory='localhost,' 'loca
 }
 ```
 
+## Handlers
+
+Blocks and `import_tasks` tend to make the handlers unreachable.
+
+Instead of using blocks, give the same listen string to all involved handlers:
+
+```diff
+- - name: Block name
+-   block:
+-     - name: First task
+-       …
+-     - name: N-th task
+-       …
++ - name: First task
++   listen: Block name
++   …
++ - name: N-th task
++   listen: Block name
++   …
+```
+
+Instead of using `ìmport_tasks`, use `include_tasks`:
+
+```diff
+  - name: First task
+-   import_tasks: tasks.yml
++   include_tasks: tasks.yml
+```
+
+Handlers **can** notify other handlers:
+
+```yaml
+- name: Configure Nginx
+  ansible.builtin.copy: …
+  notify: Restart Nginx
+
+- name: Restart Nginx
+  ansible.builtin.copy: …
+```
+
 ## Roles
 
 ### Get roles
diff --git a/snippets/ansible/tasks.yml b/snippets/ansible/tasks.yml
index 2eeb99c..44f5b8c 100644
--- a/snippets/ansible/tasks.yml
+++ b/snippets/ansible/tasks.yml
@@ -402,7 +402,10 @@
           register: instance_check
           retries: 12
           delay: 15
-          until: instance_check.instances[0].pending_modified_values.keys() | length > 0
+          until: instance_check.instances[0].pending_modified_values.keys() | length == 0
+    - name: Wait for AWS to realize some requests have been made
+      ansible.builtin.pause:
+        seconds: 60
 
 - name: Send messages to Slack channels
   vars: