Merge pull request #22262 from aevesdocker/ENGDOCS-2489

ENGDOCS-2489

Author: aevesdocker

content/reference/compose-file/merge.md

@@ -142,7 +142,7 @@ services:
 
 In addition to the previously described mechanism, an override Compose file can also be used to remove elements from your application model.
 For this purpose, the custom [YAML tag](https://yaml.org/spec/1.2.2/#24-tags) `!reset` can be set to
-override a value set by the overriden Compose file. A valid value for attribute must be provided,
+override a value set by the overridden Compose file. A valid value for attribute must be provided,
 but will be ignored and target attribute will be set with type's default value or `null`. 
 
 For readability, it is recommended to explicitly set the attribute value to the null (`null`) or empty

content/reference/compose-file/networks.md

@@ -62,6 +62,40 @@ networks:
 
 The advanced example shows a Compose file which defines two custom networks. The `proxy` service is isolated from the `db` service, because they do not share a network in common. Only `app` can talk to both.
 
+## The default network
+
+When a Compose file doesn't declare explicit networks, Compose uses an implicit `default` network. Services without an explicit [`networks`](services.md#networks) declaration are connected by Compose to this `default` network:
+
+
+```yml
+services:
+  some-service:
+    image: foo
+```
+This example is actually equivalent to:
+
+```yml
+services:
+  some-service:
+    image: foo
+    networks:
+      default: {}  
+networks:
+  default: {}      
+```
+
+You can customize the `default` network with an explicit declaration:
+
+```yml
+networks:
+  default: 
+    name: a_network # Use a custom name
+    driver_opts:    # pass options to driver for network creation
+      com.docker.network.bridge.host_binding_ipv4: 127.0.0.1
+```
+
+For options, see the [Docker Engine docs](https://docs.docker.com/engine/network/drivers/bridge/#options).
+
 ## Attributes
 
 ### `driver`

content/reference/compose-file/services.md

@@ -1321,6 +1321,28 @@ services:
 ```
 For more information about the `networks` top-level element, see [Networks](networks.md).
 
+### Implicit default network
+
+If `networks` is empty or absent from the Compose file, Compose considers an implicit definition for the service to be
+connected to the `default` network: 
+
+```yml
+services:
+  some-service:
+    image: foo
+```
+This example is actually equivalent to:
+
+```yml
+services:
+  some-service:
+    image: foo  
+    networks:
+      default: {}  
+```
+
+If you want the service to not be connected a network, you must set [`network_mode: none`](#network_mode).
+
 #### `aliases`
 
 `aliases` declares alternative hostnames for the service on the network. Other containers on the same
@@ -1675,13 +1697,23 @@ services:
 
 `pull_policy` defines the decisions Compose makes when it starts to pull images. Possible values are:
 
-* `always`: Compose always pulls the image from the registry.
-* `never`: Compose doesn't pull the image from a registry and relies on the platform cached image.
+- `always`: Compose always pulls the image from the registry.
+- `never`: Compose doesn't pull the image from a registry and relies on the platform cached image.
    If there is no cached image, a failure is reported.
-* `missing`: Compose pulls the image only if it's not available in the platform cache.
+- `missing`: Compose pulls the image only if it's not available in the platform cache.
    This is the default option if you are not also using the [Compose Build Specification](build.md).
   `if_not_present` is considered an alias for this value for backward compatibility.
-* `build`: Compose builds the image. Compose rebuilds the image if it's already present.
+- `build`: Compose builds the image. Compose rebuilds the image if it's already present.
+- `daily`: Compose checks the registry for image updates if the last pull took place more than 24 hours ago.
+- `weekly`: Compose checks the registry for image updates if the last pull took place more than 7 days ago.
+- `every_<duration>`: Compose checks the registry for image updates if the last pull took place before `<duration>`. Duration can be expressed in weeks (`w`), days (`d`), hours (`h`), minutes (`m`), seconds (`s`) or a combination of these.
+
+```yaml
+services:
+  test:
+    image: nginx
+    pull_policy: every_12h
+```
 
 ### `read_only`
 
@@ -1779,6 +1811,8 @@ the service's containers.
   The default value is world-readable permissions (mode `0444`).
   The writable bit must be ignored if set. The executable bit may be set. 
 
+Note that support for `uid`, `gid`, and `mode` attributes are not implemented in Docker Compose when the source of the secret is a [`file`](secrets.md). This is because bind-mounts used under the hood don't allow uid remapping.
+
 The following example sets the name of the `server-certificate` secret file to `server.cert`
 within the container, sets the mode to `0440` (group-readable), and sets the user and group
 to `103`. The value of `server-certificate` is set