feat(backend): check free memory (#776)

* test(backend): test free memory error

issue #746

* feat(frontend): show request error if any

issue #746

* feat(backend): check free VM memory

closes issue #746

* wip(backend): check real free memory available

Before we could be misleaded by the use of
overcommitting memory allocation

issue #746

lib/Ravada.pm

@@ -1020,6 +1020,7 @@ sub _upgrade_tables {
 
     $self->_upgrade_table('vms','vm_type',"char(20) NOT NULL DEFAULT 'KVM'");
     $self->_upgrade_table('vms','connection_args',"text DEFAULT NULL");
+    $self->_upgrade_table('vms','min_free_memory',"text DEFAULT NULL");
 
     $self->_upgrade_table('requests','at_time','int(11) DEFAULT NULL');
 

lib/Ravada/Domain.pm

@@ -223,6 +223,7 @@ sub _start_preconditions{
         _allow_manage(@_);
     }
     $self->_check_free_memory();
+    $self->_check_free_vm_memory();
     _check_used_memory(@_);
 
 }
@@ -410,6 +411,24 @@ sub _check_free_memory{
         if ( $stat->memstats->{realfree} < $MIN_FREE_MEMORY );
 }
 
+sub _check_free_vm_memory {
+    my $self = shift;
+
+    return if !$self->_vm->min_free_memory;
+    return if $self->_vm->free_memory > $self->_vm->min_free_memory;
+
+    die "ERROR: No free memory. Only "._gb($self->_vm->free_memory)." out of "
+        ._gb($self->_vm->min_free_memory)." GB required.\n";
+}
+
+sub _gb($mem=0) {
+    my $gb = $mem / 1024 / 1024 ;
+
+    $gb =~ s/(\d+\.\d).*/$1/;
+    return ($gb);
+
+}
+
 sub _check_used_memory {
     my $self = shift;
     my $used_memory = 0;

lib/Ravada/VM.pm

@@ -47,6 +47,8 @@ requires 'import_domain';
 requires 'ping';
 
 requires 'is_active';
+
+requires 'free_memory';
 ############################################################
 
 has 'host' => (
@@ -472,6 +474,18 @@ sub default_storage_pool_name {
     return $self->_data('default_storage');
 }
 
+=head2 min_free_memory
+
+Returns the minimun free memory necessary to start a new virtual machine
+
+=cut
+
+sub min_free_memory {
+    my $self = shift;
+    return $self->_data('min_free_memory');
+}
+
+
 =head2 list_drivers
 
 Lists the drivers available for this Virtual Machine Manager

lib/Ravada/VM/KVM.pm

@@ -1930,4 +1930,24 @@ sub is_active($self) {
     return 0;
 }
 
+sub free_memory($self) {
+    return $self->_free_memory_available();
+}
+
+# TODO: enable this check from free memory with a config flag
+#   though I don't think it would be suitable to use
+#   Insights welcome
+sub _free_memory_overcommit($self) {
+    my $info = $self->vm->get_node_memory_stats();
+    return ($info->{free} + $info->{buffers} + $info->{cached});
+}
+
+sub _free_memory_available($self) {
+    my $info = $self->vm->get_node_memory_stats();
+    my $used = 0;
+    for my $domain ( $self->list_domains(active => 1) ) {
+        $used += $domain->domain->get_info->{memory};
+    }
+    return $info->{total} - $used;
+}
 1;

lib/Ravada/VM/Void.pm

@@ -179,6 +179,7 @@ sub ping { return 1 }
 
 sub is_active { return 1 }
 
+sub free_memory { return 1000 * 1000}
 #########################################################################3
 
 1;

t/vm/m10_freemem.t

+#!perl
+
+use strict;
+use warnings;
+
+use Data::Dumper;
+use Test::More;
+use Test::SQL::Data;
+
+use lib 't/lib';
+use Test::Ravada;
+
+my $test = Test::SQL::Data->new(config => 't/etc/sql.conf');
+
+init($test->connector);
+clean();
+
+#################################################################################
+
+sub test_min_freemem {
+    my $vm = shift;
+
+    my $sth = $test->connector->dbh->prepare(
+        "UPDATE vms SET min_free_memory=? "
+        ." WHERE id=?"
+    );
+
+    my $min_free_memory = $vm->free_memory * 2;
+
+    ok($min_free_memory > 0
+        && $min_free_memory !~ /^0+\.0+$/
+        ,"[".$vm->type."] Expecting some free memory on the VM , got $min_free_memory");
+    $sth->execute( $min_free_memory, $vm->id );
+    $sth->finish;
+
+    my $type = $vm->type;
+    $type = 'KVM'   if $type =~ /qemu/i;
+
+    $vm->disconnect;
+    delete $vm->{_data};
+
+
+    ok($vm) or return;
+    is($vm->min_free_memory, $min_free_memory) or exit;
+
+    my $domain = create_domain($vm->type);
+    my $req = Ravada::Request->start_domain(
+               uid => user_admin->id
+        ,id_domain => $domain->id
+        ,remote_ip => 'localhost'
+    );
+    ok($req);
+    rvd_back->_process_requests_dont_fork();
+    is($req->status, 'done');
+    like($req->error, qr'memory'i);
+
+    $domain->remove(user_admin);
+}
+#################################################################################
+
+for my $vm_name ( vm_names() ) {
+
+    init($test->connector, 't/etc/ravada_freemem.conf');
+    my $vm;
+    eval { $vm = rvd_back->search_vm($vm_name) };
+    warn $@ if $@;
+
+    SKIP: {
+        my $msg = "SKIPPED test: No $vm_name VM found ";
+        if ($vm && $vm_name =~ /kvm/i && $>) {
+            $msg = "SKIPPED: Test must run as root";
+            $vm = undef;
+        }
+
+        diag($msg)      if !$vm;
+        skip $msg       if !$vm;
+
+        diag("Testing free mem on $vm_name");
+
+        test_min_freemem($vm);
+
+    }
+}
+
+clean();
+
+done_testing();
+

templates/main/run_request.html.ep

@@ -60,7 +60,9 @@
             </div>
             <div class="panel-body"
                 ng-show="domain && request.status == 'done' && !domain.is_active">
-                 The machine has shut down. <button type="submit" onclick="location.reload('forceGet')">Start again</button>
+                <div ng-show="request.error">{{request.error}}</div>
+                <div ng-show="request.error == ''">The machine has shut down.</div>
+                 <button type="submit" onclick="location.reload('forceGet')">Start again</button>
             </div>
 
         </div>