Physical deployment topologies
Before addressing virtualized environments, you will start by modeling a simpler scenario: representing the deployment of an application into an operating system that is, in turn, installed on a specific server. Several important concepts that you need to understand later in this tutorial are built in this section.
You will use the following units to successfully model this scenario, all of them present in the palette that is, by default, on the right side of the screen, next to the diagram editor.
- LDAP Server: Found in the Middleware templates
- Power Server: Found in the Hardware templates
- x86 Server: Also found in the Hardware templates
- AIX 5L: Found in the Operating Systems templates
- Linux: Also found in the Operating Systems templates
- Drag LDAP Server into the diagram, and notice the warning icon in the bottom-left corner. (See Figure 5.)
Clicking it will display information about the error that was detected. When no errors are found, the icon turns into a blue icon with an i in it (lowercase letter i). If you click, it will display information, including optional actions that could be useful but aren't strictly required. This is very useful, though, and should be used constantly, because it provides real-time information concerning the consistency of the model, as well as being a huge time-saver, because the proposed actions are not only context-sensitive but take the surrounding environment into consideration.
Figure 5. Adding the LDAP server to the topology
- Click the warning icon. As Figure 6 indicates, the LDAP server needs to be hosted in an operating system.
Figure 6. Warning message about the LDAP server
- IBM® AIX 5L™ for POWER™ is a UNIX operating system, so add it to the diagram: drag the AIX 5L template into the diagram.
You now have a representation of an AIX deployment. If you look at the warning icon, you will notice that this unit also contains warnings. But focus on the LDAP Server for now and leave the AIX warnings for latter.
- Click the LDAP Server warning again, and this time, click the specific entry that it contains: "Unit ('LDAP Server') must be hosted (OperatingSystem)." One of the actions suggested is to host it on the no hostname unit, which is the AIX instance that you added but haven't properly named yet.
- Select that option by selecting that action in the lower pane and double-clicking it. This will host the LDAP Server unit in the AIX instance.
Figure 7. Using proposed actions
Notice that the warning has disappeared from the LDAP Server, which means that all mandatory requirements are now met. There is a hosting link between the LDAP Server and the AIX instance, as shown in Figure 8.
Figure 8. LDAP server hosted on an AIX instance
Different relationships have different links. Hosting is represented by an arrow with two parallel lines. Later in this tutorial, you will see how dependencies and membership relationships have different visual queues.
It's time for you to take a look at the AIX unit, which, as mentioned earlier, contained warnings.
- Click on the warning icon of that unit. A list of errors will appear (see Figure 9) that includes the need to set the hostname, the root password, and to host the operating system is a physical server.
Figure 9. AIX instance warnings
You will tackle the issues concerning the hostname and the root password first.
- Following the previously explained method of selecting each error and
choosing a proposed action, name the AIX host
gemini(by using the Set hostname action proposed for the "hostname" is undefined error), and set the root password to
123to address the userPassword is undefined error under the root user.
- Click the warning icon again will present a final error regarding the lack of host (Figure 10).
Figure 10. AIX hosting requirement warning
The AIX instance must be hosted on a server. To find out more about this requirement take a look, as noted above, in the Requirements tab in the Properties unit, which is at the bottom of the screen, by default.
Figure 11. Viewing the AIX unit requirements
The requirement specifies that AIX can be hosted in any unit with the server.Server capability, which includes x86 servers. This can seem strange, but upon further inspection you will note that there is one constraint for this requirement. Click on the Constraints tab in the Properties view.
Figure 12. AIX hosting constraint
The constraint specifies that the server hosting it must implement the PowerPC architecture. To test this drop two server units into the diagram: a Power Server and a x86 Server.
Figure 13. Adding servers
In Rational Software Architect there are several ways to perform the action so you will use a different method to host this unit. Place the pointer over the AIX unit. This will display a yellow arrow. Click on it and drag it to an empty space. A pop-up will appear asking the type of relationship we want to indicate. Choose Hosting link.
Figure 14. Using link discovery
Rational Software Architect will present a list of option that are compatible with the requirements. Since as you have seen before there is a mandatory requirement regarding the CPU architecture that can host an AIX instance only the Power Server unit appears on the list. Select it and click OK.
Figure 15. Hosting link matching
The AIX instance is now hosted and all warnings have disappeared from it, as shown in Figure 16. The Power Server doesn't have any requirements, so it never did display a warning.
Figure 16. AIX instance hosted on Power server
Follow the same procedure to add a Linux unit and another LDAP Server unit, host the Linux unit in the x86 server and the new LDAP Server in the Linux unit.
Figure 17. AIX and Linux final stacks
In terms of visual style you are seeing the units hosted outside of their host, with a hosting link indicating the relationship. Depending on the purpose it can be useful to have a more compact view. This is easily achievable via the Show Unit on Host toolbar options or by simply dragging the unit into the host. This also works to create a new hosting relationship should one not exist. Dragging the units outside has the reverse effect.
You can mix and match different visual arrangements inside the same diagram. This can be useful to give a different focus to particular components. Figure 18 shows the two different stacks arranged in different ways.
Figure 18. Different ways to view hosting relationships
Now that you have successfully experimented with physical deployments, it is time to see what changes when introducing virtualization options. The next sections give an overview of some of the possibilities.