Hi,

I found a easy way to reproduce.

sudo systemctl restart systemd-journald
# then configure your hostname

everytime, restart of systemd-journald cause corruption of vyos-hostsd, and then configuring hostname cause restart of vyos-hostsd, and it eventually cause restart of vyos-router, and vyos is reconfigured unexpectably.

best regards.

Hi @zsdc ,

Really thanks for your reply. It's nice to have this fix. But to be honest, crash of vyos-hostsd is not so big deal for me, what really concern me is that restart of vyos-hostsd is followed by restart of vyos-router.

In my understanding, vyos-router should only be called on boot time in most of case, we should avoid it's called in running phase if it's unintentional. I have checked unit file of vyos-hostsd, it uses RequiredBy as following:

[Install]
RequiredBy=cloud-init-local.service vyos-router.service

It means that no matter what condition is, as long as vyos-hostsd is restarted, vyos-router will be restarted. I admit that this binding is necessary in boot phase when the configuration is unloaded, but it's unnecessary in running phase when configuration is already loaded, it's not safe.

Is it possible to unbind relationship between vyos-hostsd and vyos-router in running phase?

best regards.

Hello, @MapleWang!
Unfortunately, I cannot find any other reliable way to configure vyos-hostsd service to be running before the vyos-router. In fact, vyos-hostsd is really necessary to be running for proper work of the VyOS system, so we can consider this even from the other point of view - how to keep all services operable after the vyos-router restart?
If you will have any ideas, which can help to decrease the overall impact of this situation, we would be happy to get them.

Hi @zsdc

My original thoughts was quite straight forward, modify /usr/libexec/vyos/init/vyos-router as below:

start()
{
    # in the last line of start phase, add a flag file in temporary file system like
    touch /tmp/vyos-router
}

# add new restart phase
case "$action" in
     start)  start ;;
     stop)  stop ;;
     restart)  restart ;;
     force-reload)  stop && start ;;
esac

restart()
{
    # check if the flag exists, if it exists, it means the system is running, then don't allow related restart
    if [ -e "/tmp/vyos-router" ]
    then
        return
    else
       stop && start
    fi  
}

But the truth is the restart phase defined in /usr/libexec/vyos/init/vyos-router won't be used by systemd at all, I checked document of systemd, it seems restart in systemd just call "Execstop && Execstart", there is no way to specify execution command for restart action. Then it would be awkward to implement my thoughts above. But hope it give you some hints to fix this problem.

best regards

Hi @zsdc

Why not use WantedBy instead of RequiredBy in vyos-hostsd.service like:

[Install]
WantedBy=cloud-init-local.service vyos-router.service

It can maintain relationship vyos-hostsd and vyos-router in startup phase and also won't lead to problem we described above in running phase.

By the way, may I say there are several bugs of stop function in vyos-router?

It's original code:

local -i status=-1
log_daemon_msg "Stopping VyOS router"
for ((i=${#sub_inits[@]} - 1; i >= 0; i--)) ; do
    s=${subinit[$i]}
    log_progress_msg $s
    ${vyatta_sbindir}/${s}.init stop
    let status\|=$?
done
log_end_msg $status
log_action_begin_msg "Un-mounting VyOS Config"
umount ${vyatta_configdir}
log_action_end_msg $?

/usr/lib/frr/frr stop

sub_inits should be subinit and frr should be frrinit.sh