diff --git a/lib/do_instance/do_create.js b/lib/do_instance/do_create.js
index 0562dc1..6b4386e 100644
--- a/lib/do_instance/do_create.js
+++ b/lib/do_instance/do_create.js
@@ -217,6 +217,19 @@ function do_create(subcmd, opts, args, cb) {
                 next();
             });
         },
+        function loadAddl(ctx, next) {
+            mat.addlFromCreateOpts(opts, log, function (err, addl) {
+                if (err) {
+                    next(err);
+                    return;
+                }
+                if (addl) {
+                    log.trace({addl: addl}, 'additional parameters loaded from opts');
+                    ctx.addl = addl;
+                }
+                next();
+            });
+        },
         function getImg(ctx, next) {
             var _opts = {
                 name: args[0],
@@ -294,6 +307,11 @@ function do_create(subcmd, opts, args, cb) {
                     createOpts['tag.'+key] = ctx.tags[key];
                 });
             }
+            if (ctx.addl) {
+                Object.keys(ctx.addl).forEach(function (key) {
+                    createOpts[key] = ctx.addl[key];
+                });
+            }
 
             for (var i = 0; i < opts._order.length; i++) {
                 var opt = opts._order[i];
@@ -427,7 +445,17 @@ do_create.options = [
             '`INST`. Use this option more than once for multiple rules.',
         completionType: 'tritonaffinityrule'
     },
-
+    {
+        names: ['addl'],
+        type: 'arrayOfString',
+        helpArg: 'ADDL',
+        help: 'Add specific properties when creating the instance. These are ' +
+            'key/value pairs available on the instance API object at the ' +
+            'top level. ADDL is one of: a "key=value" string (bool and ' +
+            'numeric "value" are converted to that type), a JSON object ' +
+            '(if first char is "{"), or a "@FILE" to have properties be ' +
+            'loaded from FILE. This option can be used multiple times.'
+    },
     {
         group: ''
     },
diff --git a/lib/metadataandtags.js b/lib/metadataandtags.js
index e9438a6..07172a2 100644
--- a/lib/metadataandtags.js
+++ b/lib/metadataandtags.js
@@ -123,6 +123,52 @@ function tagsFromCreateOpts(opts, log, cb) {
 }
 
 
+/*
+ * Load and validate additional parameters from these options:
+ *      --addl-opts DATA
+ *
+ * <https://github.com/joyent/sdc-vmapi/blob/master/docs/index.md#vm-metadata>
+ * says values may be string, num or bool.
+ */
+function addlFromCreateOpts(opts, log, cb) {
+    assert.arrayOfObject(opts._order, 'opts._order');
+    assert.object(log, 'log');
+    assert.func(cb, 'cb');
+
+    var addl = {};
+
+    vasync.forEachPipeline({
+        inputs: opts._order,
+        func: function addlFromOpt(o, next) {
+            log.trace({opt: o}, 'addlFromOpt');
+            if (o.key === 'addl') {
+                if (!o.value) {
+                    next(new errors.UsageError(
+                        'empty additional parameters option value'));
+                    return;
+                } else if (o.value[0] === '{') {
+                    _addMetadataFromJsonStr('addl', addl, o.value, null, next);
+                } else if (o.value[0] === '@') {
+                    _addMetadataFromFile('addl', addl, o.value.slice(1), next);
+                } else {
+                    _addMetadataFromKvStr('addl', addl, o.value, null, next);
+                }
+            } else {
+                next();
+            }
+        }
+    }, function (err) {
+        if (err) {
+            cb(err);
+        } else if (Object.keys(addl).length) {
+            cb(null, addl);
+        } else {
+            cb();
+        }
+    });
+}
+
+
 /*
  * Load and validate tags from (a) these options:
  *      -f,--file FILE
@@ -342,6 +388,7 @@ function _addMetadatumFromFile(ilk, metadata, key, file, from, cb) {
 
 
 module.exports = {
+    addlFromCreateOpts: addlFromCreateOpts,
     metadataFromOpts: metadataFromOpts,
     tagsFromCreateOpts: tagsFromCreateOpts,
     tagsFromSetArgs: tagsFromSetArgs