reference docs for [deploy.release_command_vm]

reference/configuration.html.markerb

@@ -181,9 +181,19 @@
 
 The `release_command` value replaces `CMD` in the temporary Machine. This is useful for running database migrations before app Machines are created or updated with the new release. Note that the Docker image's `ENTRYPOINT` is not overridden by the `release_command`; `ENTRYPOINT` always runs.
 
-The temporary Machine has full access to the network, environment variables and secrets, but *not* to persistent volumes. Changes made to the file system on the temporary Machine will not be retained or deployed. The building/compiling of your project should be done in your Dockerfile. If you need to modify persistent volumes or configure your application, consider making use of `CMD` or `ENTRYPOINT` in your Dockerfile, or of a [process group command](#the-processes-section).
+By default, the temporary Machine has full access to the network, environment variables and secrets, but *not* to persistent volumes. Changes made to the file system on the temporary Machine will not be retained or deployed. The building/compiling of your project should be done in your Dockerfile. If you need to modify persistent volumes or configure your application, consider making use of `CMD` or `ENTRYPOINT` in your Dockerfile, or of a [process group command](#the-processes-section).
 
 The temporary Machine inherits the size from the largest Machine in the default process group of the app as of flyctl v0.0.508 (they also default larger on empty/new apps, using the Machine `shared-cpu-2x` preset). The default process group is defined as either the `app` process, or the first process group in alphabetical order (if an `app` process is not present).
+It is also possible to explicitly define the Machine size by setting `[deploy.release_command_vm]`  like in:
+
+```toml
+[deploy]
+  release_command = "bin/rails db:prepare"
+
+  [deploy.release_command_vm]
+    size = "performance-1x"
+    memory = "8gb"
+```
 
 A non-zero exit status from this command will stop the deployment. `fly deploy` will display logs from the command. Logs are available via `fly logs` as well.
 
@@ -681,7 +691,7 @@
 * `kill_signal`: The signal to send to the test process if it runs too long. Defaults to the signal of the image, if a custom image is set.
 * `kill_timeout`: The time to wait before sending the kill signal. Defaults to the timeout of the image, if a custom image is set.
 
 Machine checks are especially useful for canary deploys. `flyctl` will spawn a new Machine, ensure all machine capabilities are functional, and then deploy the rest of the Machines in your app.
 
 ## The `mounts` section
 
@@ -848,13 +858,13 @@
   processes = ["app"]
 ```
 
 When a machine unexpectedly exits, our scheduling machinery follows a machine’s restart policy to restart it without your intervention. These policies are quite similar to docker’s container restart policies:
 
 - always: we’ll attempt to restart the machine no matter the exit code.
 - never: we won’t restart the machine even if it exits with a non-zero exit code.
 - on-failure: we’ll only restart the machine if it exited with a non-zero exit code (due to a failure or crash). This is the default policy if one is not explicitly set. 
 
 A restart policy can be targeted to a specific process group. If a group is not specified, all machines in an app will have the same default restart policy. You can also specify the number of times we should retry restarting the machine before giving up.
 
 ## The `checks` section
 
@@ -975,7 +985,7 @@
 
 The "guest path" --- the path inside your container where the files to serve are located --- can overlap with other static mappings; the URL prefix should not (so, two mappings to `/public/foo` and `/public/bar` are fine, but two mappings to `/public` are not).
 
 Alternatively, you can serve statics directly from object storage using [Tigris](/docs/tigris/). Similar to machine statics, requests under `url_prefix` are served from static assets in your Tigris bucket under `guest_path`. The same rules apply for overlapping URL prefixes.
 
 ```toml
 [[statics]]