var columnDefs = [
                   {headerName: "Workload", field: "workload"},
                   {headerName: "units", "field": "units"}
                 ];

$scope.gridOptionsObject = {
                            columnDefs: columnDefs,
                            rowData: $scope.rowData,
                            headerCellRenderer: (params) =>
                                {return headerCellRendererFunc(params)}
                        };

var headerCellRendererFunc = function(params) {
            var headerColDef = params.colDef;
            headerColDef.name =  headerColDef.headerName;
            headerColDef.isMetadata = false;
            return '<h1 column="headerColDef"></h1>';
        }

var header_template = '<span class="text-danger" style="height:30px;">Some Value </span>';

columnDefs = [];
customColumn = {headerName: header_template, field: name};
columnDefs.push(customColumn);

return '<h1 column="headerColDef">' + headerColDef.name + '</h1>';

headerCellTemplate = function () {
                    var eCell = document.createElement('span');
                    eCell.innerHTML = '<div></div>'
                    return eCell;
                };