migrate "Using local runner images" docs

weaken docker requirement
document action offline mode

Author: ChristopherHX

src/installation/index.md

@@ -2,7 +2,7 @@
 
 ## Necessary prerequisites for running `act`
 
-`act` depends on `docker` (exactly Docker Engine API) to run workflows.
+`act` depends on `docker` (exactly Docker Engine API) to run workflows in containers. As long you don't require container isolation, you can run selected (e.g. windows or macOS) jobs directly on your System see [Runners](../usage/runners.md). In the latter case you don't need to have docker installed or running.
 
 If you are using macOS, please be sure to follow the steps outlined in [Docker Docs for how to install Docker Desktop for Mac](https://docs.docker.com/docker-for-mac/install/).
 

src/usage/index.md

@@ -283,3 +283,23 @@ This will trigger the workflow to use the following matrix configurations only:
 - `os: macos-latest, node 10`
 
 Note that using the `--matrix` flag you can't add new values (for e.g. running the above workflow for node 20). It will simply ignore it. Moreover, the `exclude` field in the workflow will take precedance over the `--matrix` flag (for e.g. running the above workflow for only macos-latest and node 4 will result in no matrix configuration being used)
+
+## Action Offline Mode
+
+If you want to speed up running act and using cached actions and container images you can enable this mode.
+
+- stops pulling existing images
+- stops failing if an action has been cached and you cannot connect to GitHub
+- pulls non existent actions and images
+- act will work offline if it has at least ran once while you are online
+- get rid of unnecessary timeouts when you have an unstable connection to GitHub or Container registries
+- workaround rate limit problems
+
+```sh
+  act --action-offline-mode
+```
+
+or a `.actrc` file in your cwd like
+```
+--action-offline-mode
+```

src/usage/runners.md

@@ -39,7 +39,7 @@ If you need an environment that works just like the corresponding GitHub runner
 
 - [`catthehacker/ubuntu:full-*`](https://github.com/catthehacker/docker_images/pkgs/container/ubuntu) - filesystem dump of the Runners provided by GitHub, see [`ChristopherHX/runner-image-blobs`](https://github.com/ChristopherHX/runner-image-blobs) or [`catthehacker/docker_images`](https://github.com/catthehacker/docker_images) for more information
 
-## Use an alternative runner image
+### Use an alternative runner image
 
 To use a different image for the runner, use the `-P` option.
 
@@ -59,3 +59,18 @@ For example, if your workflow uses `ubuntu-18.04`, `ubuntu-16.04` and `ubuntu-la
 ```sh
 act -P ubuntu-18.04=nektos/act-environments-ubuntu:18.04 -P ubuntu-latest=ubuntu:latest -P ubuntu-16.04=node:16-buster-slim
 ```
+
+### Using local runner images
+
+The `--pull` flag is set to true by default due to a breaking on older default docker images. This would pull the docker image everytime act is executed.
+
+Set `--pull` to false if a local docker image is needed
+```sh
+  act --pull=false
+```
+
+Alternatively turn on offline mode
+
+```sh
+  act --action-offline-mode
+```