[Bug]: jean-server --headless accumulates zombie node-MainThread processes on Ubuntu

[rchrdkvcs]

Describe the issue

Summary

When running jean-server directly on an Ubuntu host in headless mode through systemd, zombie processes progressively accumulate under the main jean-server process.

The zombies appear as (node-MainThread) processes in pstree, and their number continues to grow while the server is running.

Environment

• Jean version: 0.1.72
• OS: Ubuntu 24.04.4 LTS (Noble Numbat)
• Kernel: 6.8.0-138-generic
• Architecture: x86_64
• Runtime: Native Linux host, not Docker
• Launch method: systemd
• Command: /usr/local/bin/jean-server --headless

Systemd unit

[Unit]
Description=Jean headless server
Documentation=https://github.com/coollabsio/jean
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
User=rchrdkvcs
Group=rchrdkvcs
EnvironmentFile=-/etc/jean-server.env
ExecStart=/usr/local/bin/jean-server --headless
Restart=on-failure
RestartSec=5
TimeoutStopSec=20

[Install]
WantedBy=multi-user.target

Actual behavior

jean-server remains the parent of a growing list of zombie node-MainThread processes:

root@home:~# pstree -aps 1338
systemd,1
  └─jean-server,1338 --headless
      ├─bash,210284
      ├─(node-MainThread,6183)
      ├─(node-MainThread,22303)
      ├─(node-MainThread,22624)
      ├─(node-MainThread,24656)
      ├─(node-MainThread,43025)
      ├─(node-MainThread,43193)
      ├─(node-MainThread,61709)
      ├─(node-MainThread,62464)
      ├─(node-MainThread,80221)
      ├─(node-MainThread,80947)
      ├─(node-MainThread,98609)
      ├─(node-MainThread,99430)
      ├─...
      ├─(node-MainThread,4181055)
      ├─{jean-server},1363
      ├─{jean-server},1364
      └─{jean-server},210285

The complete output contains a very large number of (node-MainThread) entries. In pstree, the parentheses indicate zombie processes.

Expected behavior

Child processes spawned by jean-server should be properly reaped after they exit. The number of zombie processes should not grow indefinitely during normal operation.

Investigation requested

Please investigate the child-process lifecycle and process reaping in headless mode, especially whether exited node-MainThread child processes are correctly handled and waited for by the server process.

Replication

1. Install and run jean-server directly on an Ubuntu host.
2. Start it in headless mode as a systemd service.
3. Leave the service running.
4. Inspect the process tree periodically:

pstree -aps "$(pgrep -xo jean-server)"
ps -eo pid,ppid,user,stat,comm,args | awk '$4 ~ /^Z/'

How are you running Jean?

Headless

Operating system

Ubuntu 24.04 - Server

Jean version

0.1.72

How are you interacting with Jean?

Via the web