Provide parallel_one_host_only via workers config file

docs/WritingTests.asciidoc

@@ -672,8 +672,8 @@ eventually workers can be held back for the cluster.
 It is possible to ensure that all jobs within the same _parallel_ cluster are
 executed on the same worker host. This is useful for connecting the SUTs without
 having to connect the physical worker hosts. Use `PARALLEL_ONE_HOST_ONLY=1` to
-enable this. Note that adding this setting in `workers.ini` has currently *no*
-effect.
+enable this. It is also possible to enable this setting as a global in
+`workers.ini`.
 
 WARNING: You need to provide enough worker slots on single worker hosts to fit
 an entire cluster. So this feature is mainly intended to workaround situations

etc/openqa/workers.ini

@@ -5,7 +5,10 @@
 [global]
 # space separated list of webuis to connect to (empty defaults to localhost)
 #HOST = http://openqa.example.host
+HOST = http://localhost:9526
 
+# Ensure that Multimachine jobs are scheduled on the same worker host.
+#PARALLEL_ONE_HOST_ONLY = 1
 # Specify a cache directory for assets and tests to sync them automatically via
 # http/rsync; the specified path is just an example but what you would usually
 # use on a normal setup
@@ -83,6 +86,15 @@
 
 # The section ids are the instance of the workers.
 # The key/value pairs will appear in vars.json
+[1]
+WORKER_CLASS = qemu_x86_64_staging,qemu_x86_64,tap
+
+[2]
+WORKER_CLASS = qemu_x86_64_staging,qemu_x86_64,tap
+#PARALLEL_ONE_HOST_ONLY = 1
+[3]
+WORKER_CLASS = qemu_x86_64_staging,qemu_x86_64,tap
+
 #[1]
 #WORKER_CLASS = 64bit-ipmi
 

lib/OpenQA/WebAPI/Controller/API/V1/Worker.pm

@@ -173,18 +173,18 @@ sub create {
     my ($self) = @_;
     my $validation = $self->validation;
     my @validation_params
-      = qw(cpu_arch cpu_modelname cpu_opmode cpu_flags mem_max isotovideo_interface_version websocket_api_version worker_class);
+      = qw(cpu_arch cpu_modelname cpu_opmode cpu_flags mem_max isotovideo_interface_version websocket_api_version worker_class parallel_one_host_only);
     $validation->required($_) for qw(host instance cpu_arch mem_max worker_class);
     $validation->optional($_)
-      for qw(cpu_modelname cpu_opmode cpu_flags isotovideo_interface_version job_id websocket_api_version);
+      for qw(cpu_modelname cpu_opmode cpu_flags isotovideo_interface_version job_id websocket_api_version  parallel_one_host_only);
     return $self->reply->validation_error({format => 'json'}) if $validation->has_error;
 
     my $host = $validation->param('host');
     my $instance = $validation->param('instance');
     my $job_ids = $validation->every_param('job_id');
     my $caps = {};
     $caps->{$_} = $validation->param($_) for @validation_params;
-
+    #print "CAPS == $caps";
     my $id;
     try {
         $id = $self->_register($self->schema, $host, $instance, $caps, $job_ids);

lib/OpenQA/Worker.pm

@@ -211,6 +211,7 @@ sub capabilities ($self) {
         $caps->{worker_class}
           = join(',', map { 'qemu_' . $_ } @{$supported_archs_by_cpu_archs{$caps->{cpu_arch}} // [$caps->{cpu_arch}]});
         # TODO: check installed qemu and kvm?
+	$caps->{parallel_one_host_only} = $global_settings->{PARALLEL_ONE_HOST_ONLY} if exists $global_settings->{PARALLEL_ONE_HOST_ONLY};
     }
 
     return $self->{_caps} = $caps;