doc: Add default-runtime opt to daemon.json

cpuguy83 · cpuguy83 · commit a90532e2902a · 2021-09-23T17:53:46.000Z
This is a new flag for the Windows daemon.

Signed-off-by: Brian Goff &lt;cpuguy83@gmail.com&gt;
diff --git a/docs/reference/commandline/dockerd.md b/docs/reference/commandline/dockerd.md
@@ -1505,6 +1505,7 @@ This is a full example of the allowed configuration options on Windows:
   "containerd-plugin-namespace": "docker-plugins",
   "data-root": "",
   "debug": true,
+  "default-runtime": "",
   "default-ulimits": {},
   "dns": [],
   "dns-opts": [],
@@ -1537,6 +1538,13 @@ This is a full example of the allowed configuration options on Windows:
 }
 ```
 
+The `default-runtime` option is by default unset, in which case dockerd will auto-detect the runtime. This detection is currently based on if the `containerd` flag is set.
+
+Accepted values:
+
+- `com.docker.hcsshim.v1` - This is the built-in runtime that Docker has used since Windows supported was first added and uses the v1 HCS API's in Windows.
+- `io.containerd.runhcs.v1` - This is uses the containerd `runhcs` shim to run the container and uses the v2 HCS API's in Windows.
+
 #### Feature options
 The optional field `features` in `daemon.json` allows users to enable or disable specific
 daemon features. For example, `{"features":{"buildkit": true}}` enables `buildkit` as the
