ndppd.service: Start request repeated too quickly.

[Hugo Herter]

The ndppd service does not like being restarted too quickly.

This leads to an error when running the command :

2023-11-14 15:50:25,641 | DEBUG | Proxying range fc00:1:2:3:1:3fc0:aa95:69d0/124 -> vmtap4
2023-11-14 15:50:25,641 | DEBUG | Restarting ndppd
2023-11-14 15:50:25,641 | DEBUG | command: systemctl restart ndppd
2023-11-14 15:50:25,647 | ERROR | Command failed with error code 1:
    stdin = None
    command = ['systemctl', 'restart', 'ndppd']
    stdout = b'Job for ndppd.service failed.\nSee "systemctl status ndppd.service" and "journalctl -xeu ndppd.service" for details.\n'
2023-11-14 15:50:25,647 | ERROR | Command '['systemctl', 'restart', 'ndppd']' returned non-zero exit status 1.
Traceback (most recent call last):
  File "/root/aleph-vm-remote/src/aleph/vm/orchestrator/run.py", line 93, in create_vm_execution_or_raise_http_error
    return await create_vm_execution(vm_hash=vm_hash, pool=pool)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/aleph-vm-remote/src/aleph/vm/orchestrator/run.py", line 60, in create_vm_execution
    execution = await pool.create_a_vm(
                ^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/aleph-vm-remote/src/aleph/vm/pool.py", line 84, in create_a_vm
    tap_interface = await self.network.create_tap(vm_id, vm_hash, vm_type)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/aleph-vm-remote/src/aleph/vm/network/hostnetwork.py", line 218, in create_tap
    await interface.create()
  File "/root/aleph-vm-remote/src/aleph/vm/network/interfaces.py", line 75, in create
    await self.ndp_proxy.add_range(self.device_name, ipv6_gateway.network)
  File "/root/aleph-vm-remote/src/aleph/vm/network/ndp_proxy.py", line 53, in add_range
    await self._update_ndppd_conf()
  File "/root/aleph-vm-remote/src/aleph/vm/network/ndp_proxy.py", line 46, in _update_ndppd_conf
    await self._restart_ndppd()
  File "/root/aleph-vm-remote/src/aleph/vm/network/ndp_proxy.py", line 35, in _restart_ndppd
    await run_in_subprocess(["systemctl", "restart", "ndppd"])
  File "/root/aleph-vm-remote/src/aleph/vm/utils.py", line 97, in run_in_subprocess
    raise subprocess.CalledProcessError(process.returncode, str(command), stderr.decode())
subprocess.CalledProcessError: Command '['systemctl', 'restart', 'ndppd']' returned non-zero exit status 1.

The issue comes from async def _update_ndppd_conf(self):, which may be called many times in a row.

The logs of the service show:

Nov 14 15:45:46 aleph-vm-lab-2 systemd[1]: Stopped ndppd.service - LSB: NDP Proxy Daemon.
Nov 14 15:45:46 aleph-vm-lab-2 systemd[1]: Starting ndppd.service - LSB: NDP Proxy Daemon...
Nov 14 15:45:46 aleph-vm-lab-2 ndppd[273602]: (notice) ndppd (NDP Proxy Daemon) version 0.2.4
Nov 14 15:45:46 aleph-vm-lab-2 ndppd[273602]: (notice) Using configuration file '/etc/ndppd.conf'
Nov 14 15:45:46 aleph-vm-lab-2 systemd[1]: Started ndppd.service - LSB: NDP Proxy Daemon.
Nov 14 15:45:47 aleph-vm-lab-2 systemd[1]: Stopping ndppd.service - LSB: NDP Proxy Daemon...
Nov 14 15:45:47 aleph-vm-lab-2 ndppd[273603]: (error) Shutting down...
Nov 14 15:45:47 aleph-vm-lab-2 ndppd[273603]: (notice) Bye
Nov 14 15:45:47 aleph-vm-lab-2 systemd[1]: ndppd.service: Deactivated successfully.
Nov 14 15:45:47 aleph-vm-lab-2 systemd[1]: Stopped ndppd.service - LSB: NDP Proxy Daemon.
Nov 14 15:45:47 aleph-vm-lab-2 systemd[1]: ndppd.service: Start request repeated too quickly.
Nov 14 15:45:47 aleph-vm-lab-2 systemd[1]: ndppd.service: Failed with result 'start-limit-hit'.
Nov 14 15:45:47 aleph-vm-lab-2 systemd[1]: Failed to start ndppd.service - LSB: NDP Proxy Daemon.
Nov 14 15:45:47 aleph-vm-lab-2 systemd[1]: ndppd.service: Start request repeated too quickly.
Nov 14 15:45:47 aleph-vm-lab-2 systemd[1]: ndppd.service: Failed with result 'start-limit-hit'.
Nov 14 15:45:47 aleph-vm-lab-2 systemd[1]: Failed to start ndppd.service - LSB: NDP Proxy Daemon.
Nov 14 15:45:48 aleph-vm-lab-2 systemd[1]: ndppd.service: Start request repeated too quickly.
Nov 14 15:45:48 aleph-vm-lab-2 systemd[1]: ndppd.service: Failed with result 'start-limit-hit'.
Nov 14 15:45:48 aleph-vm-lab-2 systemd[1]: Failed to start ndppd.service - LSB: NDP Proxy Daemon.
Nov 14 15:45:48 aleph-vm-lab-2 systemd[1]: ndppd.service: Start request repeated too quickly.
Nov 14 15:45:48 aleph-vm-lab-2 systemd[1]: ndppd.service: Failed with result 'start-limit-hit'.
Nov 14 15:45:48 aleph-vm-lab-2 systemd[1]: Failed to start ndppd.service - LSB: NDP Proxy Daemon.
Nov 14 15:45:48 aleph-vm-lab-2 systemd[1]: ndppd.service: Start request repeated too quickly.
Nov 14 15:45:48 aleph-vm-lab-2 systemd[1]: ndppd.service: Failed with result 'start-limit-hit'.
Nov 14 15:45:48 aleph-vm-lab-2 systemd[1]: Failed to start ndppd.service - LSB: NDP Proxy Daemon.