Running pas with real machines

The pas tool was originally conceived to be run on a especially configured VM setup, but it is enough flexible to be able to work on any machine if some requirements are satisfied.

This section deals with the different assumptions the pas tool makes about the guest machine and described how a real machine has to be set up in order to be compatible with pas.

Authentication

All communication between pas and the remote host happens through ssh. As the VMs are especially created for the measures, they don’t have strict security requirements and so password based authentication is used to connect to them.

Furthermore pas assumes that all remote machines share the same username and password.

To configure a real machine to be able to authenticate the pas tool, two ways are possible:

1. Configure the local host and the remote machine in order to authenticate themselves without user interaction (this is often done by using publickey authentication, but other, less secure, methods exist).

   The ssh transport layer will always try publickey authentication first thus different keys can be exchanged between different hosts and a good security level can be achieved.

2. Create a user for pas on each machine giving it the same username and password and set the VM_USER and the VM_PASSWORD directives accordingly.

Furthermore, pas requires sudo permissions to execute certain commands. On the default VM configurations, it does not need any password to execute commands as root and the real machines have to be configured to behave the same way.

The commands for which pas requires sudo privileges are to start, stop and kill the jobmgr and tshark processes and to copy and delete the files created by these.

Dependencies

When using the default VMs, vagrant automatically sets them up to conform to the pas requirements. You can directly use the chef configuration bundled with each environment or manually set up your machines to conform to these requirements.

The following packages are required by pas:

• A popc installation, configured in accordance with the role assigned to the machine.
• The tshark executable, often provided by the system package manager.
• The screen executable, often provided by the system package manager, if not already installed.
• A getip shell script available on the path which prints the IP address of the interface given as its only argument.

Shared folders

Vagrant allows to easily set up shared folders between the host and one or more guest operating systems. pas builds upon this feature to be able to distribute the source code and recover the measure results.

The following folders on the remote hosts have to be shared with the local host:

• /share/test-cases on the remote host has to be mapped to the cases directory of the test environment.
• /share/measures on the remote host has to be mapped to the reports directory of the test environment.
• /share/conf on the remote host has to be mapped to the conf directory of the test environment.

Note

These paths can be configured using the PATHS setting directive.

This means that you can adjust these paths to your liking as long as there are three shared folders between the systems and that the settings file is configured accordingly.

Note

If sharing folders is not an option, you can always build custom subcommands to override the commands which need shared folders and do the file transfers over ssh using scp or with rsync.