Merge pull request #602 from Oats87/issues/rke2/537-docs

Enhance docs for `INSTALL_RKE2_VERSION` details.

docs/install/install_options/install_options.md

@@ -23,11 +23,11 @@ When using this method to install RKE2, the following environment variables can
 
 | Environment Variable | Description |
 |-----------------------------|---------------------------------------------|
-| <span style="white-space: nowrap">`INSTALL_RKE2_VERSION`</span> | Version of RKE2 to download from GitHub. Will attempt to download from the latest channel if not specified. |
+| <span style="white-space: nowrap">`INSTALL_RKE2_VERSION`</span> | Version of RKE2 to download from GitHub. Will attempt to download the latest release from the `stable` channel if not specified. `INSTALL_RKE2_CHANNEL` should also be set if installing on an RPM-based system and the desired version does not exist in the `stable` channel. |
 | <span style="white-space: nowrap">`INSTALL_RKE2_TYPE`</span> | Type of systemd service to create, can be either "server" or "agent" Default is "server". |
 | <span style="white-space: nowrap">`INSTALL_RKE2_CHANNEL_URL`</span> | Channel URL for fetching RKE2 download URL. Defaults to https://update.rke2.io/v1-release/channels. |
-| <span style="white-space: nowrap">`INSTALL_RKE2_CHANNEL`</span> | Channel to use for fetching RKE2 download URL. Defaults to "latest". Options include: `stable`, `latest`, `testing`. |
-| <span style="white-space: nowrap">`INSTALL_RKE2_METHOD`</span> | Method of installation to use. Default is on RPM-based systems "rpm", all else "tar". |
+| <span style="white-space: nowrap">`INSTALL_RKE2_CHANNEL`</span> | Channel to use for fetching RKE2 download URL. Defaults to `stable`. Options include: `stable`, `latest`, `testing`. |
+| <span style="white-space: nowrap">`INSTALL_RKE2_METHOD`</span> | Method of installation to use. Default is on RPM-based systems `rpm`, all else `tar`. |
 
 This installation script is straight-forward and will do the following: