The NDB Cluster Auto-Installer is made up of two components. The front end is a GUI client implemented as a Web page that loads and runs in a standard Web browser such as Firefox or Microsoft Internet Explorer (see Section 18.104.22.168, “NDB Cluster Auto-Installer Requirements”). The back end is a server process (ndb_setup.py) that runs on the local machine or on another host to which you have access.
These two components (client and server) communicate with each other using standard HTTP requests and responses. The back end can manage NDB Cluster software programs on any host where the back end user has granted access. If the NDB Cluster software is on a different host, the back end relies on SSH for access, using the Paramiko library for executing commands remotely (see Section 22.214.171.124, “NDB Cluster Auto-Installer Requirements”).
The remainder of this section is concerned primarily with the Web client. For more information about using the command-line tool, see Section 20.4.23, “ndb_setup.py — Start browser-based Auto-Installer for NDB Cluster ”.
NDB Cluster Auto-Installer Interface. This section describes the layout and navigation of the NDB Cluster Auto-Installer, whose Welcome screen looks similar to what is shown here when it is first opened in the Web browser:
You can access the installer UI by selecting either of the options Create New NDB Cluster or Continue Previous Cluster Configuration. A typical screen in the Auto-Installer includes the following elements:
Display panel. The central area where data regarding configuration settings and controls for changing them are displayed.
Breadcrumb navigation. Located in the top left and top center of the GUI, the breadcrumb navigation bar consists of a series of titles linking to screens that correspond to steps in the configuration of an NDB Cluster . The breadcrumb allows you to jump between these stages in arbritrary order.
Sequential navigation. This consists of a set of buttons labelled, , and , and can be found in the lower right-hand corner of the GUI. The sequential navigation is used to move between steps in the suggested order.
Settings and Help menus. These menus can be found in the top right corner of the GUI (to the right of the breadcrumb navigation bar).provides a way check and possibly alter configuration settings for the Auto-Installer; can be used to access the installer's built-in help files.
The locations of the elements just described are shown here in a typical page in the Auto-Installer; the numbers superimposed thereupon correspond to those used in the preceding list.
All of these elements except for the display panel are described in greater detail in the remainder of this section. Section 126.96.36.199, “Using the NDB Cluster Auto-Installer”, describes the panels shown in the display area as well as the functionality of each panel and the controls it contains.
Arbitrary and sequential navigation. The Auto-Installer can display any of a number of pages covering different stages in the setup and configuration of an NDB Cluster deployment. You can navigate between pages in either of two ways. The first of these is the breadcrumb trail navigation toolbar displaying the titles of the various pages (in which the title of the current page is highlighted and disabled). From these, any desired page, in any desired order, can be reached by selecting the title of the corresponding page. This toolbar is shown here:
The second navigation mechanism provided by the Auto-Installer consists of the, , and sequential navigation buttons at the bottom right of the page. These can be used to move to the next or previous page in predetermined order, or to go to the very last page. The buttons are enabled and disabled as needed, so that you cannot, for example, advance beyond the last page.
Settings and Help menus. These menus are positioned adjacent to one another in the top right corner of the GUI, as shown earlier in this section. Themenu is shown here in more detail:
The entries in themenu are described here, in the following list:
Since the SSH password is never saved, you must supply this once again at the beginning of a new session, if one is used.
Once set, the advanced parameters continue to be used in the configuration file until they are explicitly changed or reset. This is regardless of whether the advanced parameters are currently visible in the installer; in other words, disabling the menu item does not reset the values of any of these parameters.
As with the installer's navigation elements, one or more of the entries in themenu may be disabled due to choices you have made previously.
Themenu is shown here, as it appears when expanded:
Themenu provides several options, described in the following list:
The Auto-Installer also provides context-sensitive help in the form of tooltips for most input widgets. One of these tooltips is displayed when the mouse hovers over a widget or the small question mark which can sometimes appear next to a widget label.
In addition, the names of NDB Cluster configuration parameters are linked to their descriptions in the online NDB Cluster documentation, so that if you click on the name of a given parameter, the documentation for that parameter is shown in a separate window.