[nsd-users] pkill nsd create zombies

[A. Schulze]

Hi,

I build a docker container with nsd ( configure; make; make install )
With a very simple nsd.conf I could run nsd, do "pkill nsd" and see zombies.

root at 497d872b1c91:/# cat <<EOF > /usr/local/etc/nsd/nsd.conf
server:
  database: ""
  pidfile: ""
  verbosity: 9
EOF

root at 497d872b1c91:/# ps afx
    PID TTY      STAT   TIME COMMAND
     19 pts/0    Ss     0:00 bash
     28 pts/0    R+     0:00  \_ ps afx
      1 ?        Ss     0:00 /bin/sleep infinity

root at 497d872b1c91:/# nsd
[2021-02-15 16:45:08.484] nsd[29]: notice: nsd starting (NSD 4.3.5)
[2021-02-15 16:45:08.484] nsd[29]: notice: listen on ip-address ::@53 (udp) with server(s): *
[2021-02-15 16:45:08.485] nsd[29]: notice: listen on ip-address ::@53 (tcp) with server(s): *
[2021-02-15 16:45:08.485] nsd[29]: notice: listen on ip-address 0.0.0.0 at 53 (udp) with server(s): *
[2021-02-15 16:45:08.485] nsd[29]: notice: listen on ip-address 0.0.0.0 at 53 (tcp) with server(s): *

root at 497d872b1c91:/# sleep 10

root at 497d872b1c91:/# pkill nsd

root at 497d872b1c91:/# ps afx
    PID TTY      STAT   TIME COMMAND
     19 pts/0    Ss     0:00 bash
     35 pts/0    R+     0:00  \_ ps afx
      1 ?        Ss     0:00 /bin/sleep infinity
     30 ?        Zs     0:00 [nsd: xfrd] <defunct>
     32 ?        Z      0:00 [nsd: server 1] <defunct>

the container is started with "network-mode: none".

root at 497d872b1c91:/# ip address show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever

notice, NSD log "listen on ip-address ::@53" while IPv6 isn't present.

adding "do-ip6: no" to the configuration above doesn't change anything beside NSD do not listen on IPv6.

running NSD non forking add some logging:

root at 3ee5f805fbb9:/# nsd -d
[2021-02-15 16:55:18.077] nsd[35]: notice: nsd starting (NSD 4.3.5)
[2021-02-15 16:55:18.077] nsd[35]: notice: listen on ip-address 0.0.0.0 at 53 (udp) with server(s): *
[2021-02-15 16:55:18.077] nsd[35]: notice: listen on ip-address 0.0.0.0 at 53 (tcp) with server(s): *
[2021-02-15 16:55:18.255] nsd[36]: notice: nsd started (NSD 4.3.5), pid 35
^C[2021-02-15 16:55:21.463] nsd[36]: warning: signal received, shutting down...
[2021-02-15 16:55:21.463] nsd[36]: error: problems sending command 11 to server 37: Broken pipe


any ideas what else I could check / I'm doing wrong ?

Andreas