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Dunner1991
Asked: 2020-09-25 05:37:11 +0800 CST

rndc commands not working

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I have been building DNS servers on centos 7 (i inherited the these but need to make changes to repurpose them)

When I run the any rndc command it does not work i.e. when i try rndc reload i get no confirmation if it was successful, do not even get command failed

Please also note that I am using linux namespaces so the typical rndc command has a prefic of 'ip entns exec gi'

If i check /var/log/messages simultaneously i do not get any output as compared to another DNS server.

I have posted the output of the necessary services below:

/usr/lib/systemd/system/named.service

[Unit]
Description=Berkeley Internet Name Domain (DNS)
Wants=nss-lookup.target
Wants=named-setup-rndc.service
Before=nss-lookup.target
After=network.target
After=named-setup-rndc.service

[Service]
Type=forking
Environment=NAMEDCONF=/etc/named.conf
EnvironmentFile=-/etc/sysconfig/named
Environment=KRB5_KTNAME=/etc/named.keytab
PIDFile=/run/named/named.pid

ExecStartPre=/bin/bash -c 'if [ ! "$DISABLE_ZONE_CHECKING" == "yes" ]; then /usr/sbin/named-checkconf -z "$NAMEDCONF"; else echo "Checking of zone files is disabled"; fi'

ExecStart=/usr/sbin/named -u named -c ${NAMEDCONF} $OPTIONS

ExecReload=/bin/sh -c '/usr/sbin/rndc reload > /dev/null 2>&1 || /bin/kill -HUP $MAINPID'

ExecStop=/bin/sh -c '/usr/sbin/rndc stop > /dev/null 2>&1 || /bin/kill -TERM $MAINPID'

PrivateTmp=true

[Install]
WantedBy=multi-user.target

/usr/lib/systemd/system/named-setup-rndc.service

[Unit]
Description=Generate rndc key for BIND (DNS)

[Service]
Type=oneshot

ExecStart=/usr/libexec/generate-rndc-key.sh

I have tried to delete the rndc.key file and recreate using the named service but this has not worked. I am really stumped here. Anyone have any experience with this

after named restart the logs

-- Unit named-setup-rndc.service has begun starting up.
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 systemd[1]: Started Generate rndc key for BIND (DNS).
-- Subject: Unit named-setup-rndc.service has finished start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit named-setup-rndc.service has finished starting up.
-- 
-- The start-up result is done.
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 systemd[1]: Starting Berkeley Internet Name Domain (DNS)...
-- Subject: Unit named.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit named.service has begun starting up.
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: starting BIND 9.9.4-RedHat-9.9.4-74.el7_6.1 -u named -c /etc/named.conf -4
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: built with '--build=x86_64-redhat-linux-gnu' '--host=x86_64-redhat-linux-gnu' '-
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: ----------------------------------------------------
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: BIND 9 is maintained by Internet Systems Consortium,
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: Inc. (ISC), a non-profit 501(c)(3) public-benefit
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: corporation.  Support and training for BIND 9 are
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: available at https://www.isc.org/support
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: ----------------------------------------------------
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: adjusted limit on open files from 4096 to 1048576
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: found 8 CPUs, using 8 worker threads
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: using 8 UDP listeners per interface
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: using up to 21000 sockets
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: loading configuration from '/etc/named.conf'
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: reading built-in trusted keys from file '/etc/named.root.key'
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: initializing GeoIP Country (IPv4) (type 1) DB
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: GEO-106FREE 20180327 Build 1 Copyright (c) 2018 MaxMind Inc All Rights Reserved
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: initializing GeoIP Country (IPv6) (type 12) DB
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: GEO-106FREE 20180605 Build 1 Copyright (c) 2018 MaxMind Inc All Rights Reserved
Sep 24 14:01:40 DUB1-00-VM-GI_DNS1 named[12637]: GeoIP City (IPv4) (type 2) DB not available

Also i believe the debug logs are setup to be written to /var/named/data/named.run posted output below

tail -f /var/named/data/named.run
all zones loaded
running
shutting down
stopping command channel on 127.0.0.1#953
stopping command channel on ::1#953
no longer listening on 127.0.0.1#53
exiting
managed-keys-zone: loaded serial 1021
all zones loaded
running
domain-name-system bind rndc

1 Answers

  1. Best Answer

    I found the answer although it was mainly a rookie issue in my case.

    i used the strace tool and got the following error

    strace -i rndc reload
[00007f2716e56207] execve("/sbin/rndc", ["rndc", "reload"], 0x7ffc863430d0 /* 21 vars */) = -1 **ENOEXEC (Exec format error)**
[00007f2716e7fd30] open("/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3
[00007f2716e7f8e4] fstat(3, {st_mode=S_IFREG|0644, st_size=2502, ...}) = 0
[00007f2716e8936a] mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f27177d4000
[00007f2716e7ff70] read(3, "# Locale name alias data base.\n#"..., 4096) = 2502
[00007f2716e7ff70] read(3, "", 4096)    = 0
[00007f2716e80620] close(3)             = 0
[00007f2716e893f7] munmap(0x7f27177d4000, 4096) = 0
[00007f2716e7fd30] open("/usr/share/locale/en_GB.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
[00007f2716e7fd30] open("/usr/share/locale/en_GB.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
[00007f2716e7fd30] open("/usr/share/locale/en_GB/LC_MESSAGES/libc.mo", O_RDONLY) = 3
[00007f2716e7f8e4] fstat(3, {st_mode=S_IFREG|0644, st_size=1474, ...}) = 0
[00007f2716e8936a] mmap(NULL, 1474, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f27177d4000
[00007f2716dc29dc] close(3)             = 0
[00007f2716e7fd30] open("/usr/share/locale/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
[00007f2716e7fd30] open("/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
[00007f2716e7fd30] open("/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
[00007f2716e7f8e4] fstat(2, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
[00007f2716e8936a] mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f27177d3000
[00007f2716e7ffd0] write(2, "strace: exec: Exec format error\n", 32strace: exec: Exec format error
) = 32
[00007f2716e561d9] exit_group(1)        = ?
[????????????????] +++ exited with 1 +++

    This error ENOEXEC (Exec format error) in particular pointed towards a corrupt file so the steps i took to fix was to update bind via yum update, rndc is now successful

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