1 The haizea command

The main command in the Haizea system is, unsurprisingly, the haizea command. Running this command starts up the Haizea lease manager, which is then ready to receive and schedule lease requests. As described in Chapter 1, Haizea can run in one of three modes: unattended simulated mode, interactive simulated mode, and OpenNebula mode. In this chapter we will focus on the simulation modes, starting with the ``unattended'' variety. Both simulation modes, and the OpenNebula mode, will be described in more detail in the next chapters.

When running Haizea in unattended simulation mode, the inputs to Haizea are going to be the following:

The Haizea configuration file:

A text file containing all the options

A request tracefile:

A text file containing a list of lease requests. Since we are using ``simulated time'', we won't be able to use Haizea interactively (we will be able to do this when we switch to the ``real time'' mode later in the chapter). Instead, we need to provide all the lease requests beforehand.

Based on the configuration file and the lease requests, the simulator produces a schedule for those leases, which you will be able to follow through logging messages printed by Haizea. At the end of the simulation, Haizea also saves a fair amount of raw data and statistics to disk which can be used to produce reports and graphs (a module to do this for you is in the works). This particular mode, with simulated time, is particularly useful when you want to take a list of request (potentially spanning weeks or months) to see what happens when you tweak the scheduling options (without having to wait weeks or months for the result).

So, let's start by writing a configuration file specifying the simulation options (e.g., the characteristics of the simulated cluster) and the scheduling options.