Teacher vs Student auto-detection (read first)

The defining feature of cc-class is that you install the same package on every machine. After installation, each machine figures out by itself whether it is a "teacher" or a "student" — administrators do not need to do anything different per machine.

The decision is based on one thing only: the computer name (hostname).

1. The rule: which names count as "teacher"

A machine is treated as a teacher if its computer name matches any of the following (case-insensitive); otherwise it is a student.

1. Contains a teacher keyword: the name includes teacher, jiaoshi, laoshi, or the Chinese 老师.
   • e.g. teacher-01, JiaoShi, lab1-老师
2. Contains a -t / _t teacher tag: a standalone t delimited so that the character before it is -, _ or the start, and the character after it is -, _, a digit, or the end.
   • Matches: pc-t, lab-t-01, room1-t2, PC001-T
   • Does not misfire on: -test (t followed by e), team (t followed by e), host-time (t followed by i)

For technicians: the exact rule

The teacher tag is matched by the regex (^|[-_])t([-_]|[0-9]|$) (after lower-casing). The Windows installer (installer.nsi) and the Linux daemon (StudentService) embed identical logic, so the teacher app, student app and installer always agree.

Recommended naming

Role	Example computer name	Note
Teacher	teacher, teacher-01, PC-T, PC001-T	keyword or -t tag
Student	PC001, PC002, stu-01, room1-15	plain name, no teacher tag

Easiest scheme

Name the teacher machine PC001-T (ends with -T), and the students PC002, PC003, … This manual's demo environment uses exactly that: teacher PC001-T, students PC002 and PC003.

2. Cloud-desktop name precedence (important)

Many labs use cloud-desktop / diskless (IDV/VOI) solutions where many machines boot from the same image, so the OS hostname may be identical across machines. To handle this, cc-class resolves the name as follows:

1. First, read the "cloud-desktop computer name" pushed by the platform:
   • Linux: from device /dev/vdchardev;
   • Windows: from device \\.\vddsk.
2. Only if that device is absent / unreadable / empty does it fall back to the OS hostname.

In other words: cloud-desktop name > OS hostname. In a cloud-desktop environment, set the machine's cloud-desktop computer name (e.g. PC001-T) on the management platform — not just the OS hostname.

Common pitfall

If the OS hostname is PC001-T (looks like a teacher) but the cloud-desktop name pushed down is PC001 (a student), cc-class uses the cloud name PC001 and treats it as a student, so the teacher app refuses to start. When troubleshooting, trust the "cloud-desktop computer name".

3. What the decision causes (automatic behavior)

If the machine is…	TeacherApp	StudentApp	Desktop shortcut
Teacher	starts normally	exits automatically (the student app does not run on a teacher)	creates the Teacher icon only
Student	shows "not a teacher machine, will not start"	runs and auto-connects to the teacher	creates no desktop icon (keeps the desktop clean)

• The student app quietly exits on a teacher machine (returns 0, no disturbance).
• The teacher app warns and exits on a student machine. In emergencies you can add the command-line flag --no-host-check to skip the check (see FAQ).

4. Desktop shortcuts: automatic, no manual work

You do not create icons by hand. cc-class handles them per role and cleans up any leftover wrong-role icons:

• Teacher machine: a cc-class Teacher icon is placed on the desktop.
  • On Linux, the student daemon StudentService rebuilds it at every boot based on the cloud-desktop name, and automatically sets GNOME's metadata::trusted so the icon is not shown as an "untrusted application launcher" (which would make double-click do nothing).
  • On Windows, the installer creates …-Teacher.lnk based on the computer name.
• Student machine: no desktop icon at all (an entry still exists in the application menu for troubleshooting).

Actual result in the demo environment (checking the desktop folders):

# Teacher PC001-T desktop: has the teacher icon
~/Desktop/cc-class-teacher.desktop

# Student PC002 / PC003 desktops: empty (no cc-class icon)
(none)

Changed the computer name?

Just reboot. At boot the daemon re-evaluates the role with the new name and rebuilds/cleans the desktop icon — fully automatic.

5. Decision flow

                ┌─────────────────────────────┐
                │  Read "cloud-desktop name"   │
                │  Linux:   /dev/vdchardev     │
                │  Windows: \\.\vddsk          │
                └──────────────┬──────────────┘
              non-empty │ otherwise fall back
                ┌──────────────▼──────────────┐
                │      Use the OS hostname     │
                └──────────────┬──────────────┘
                               │
        name contains teacher / jiaoshi / laoshi / 老师
        or a -t / _t teacher tag?
                       ┌───────┴───────┐
                    yes│               │no
                ┌──────▼──────┐ ┌──────▼──────┐
                │   Teacher   │ │   Student   │
                │ run teacher │ │ run student │
                │ make icon   │ │ no icon     │
                └─────────────┘ └─────────────┘

Next, pick your platform 👉 Windows install ｜ Linux install