We're experiencing occasional failures with Knot crashing while running as a slave. The behavior is as follows: the slave will run for 2 months or so and then segfault. Our system automatically restarts the process, but after 15 minutes or less, the segfault happens again. This repeats until we remove the /var/lib/knot/journal and /var/lib/knot/timers directories. This seems to fix it up for a while: a newly started process will run fine for another couple of months.
More details on our setup: These systems serve a little less than a hundred zones, some of which change at a rapid rate. We have configured the servers to not flush the zone data to regular files. The server software is 2.5.7, but with the changes from the "ecs-patch" branch applied.
A while back, I tried a release from the newer branch (I'm pretty sure it was 2.6.4), but I had a problem there where some servers were falling behind the master, as evidenced by their SOA serial number. Diagnosing this on a more recent branch probably makes more sense, but I'd be a little leery of dealing with two problems, not just one.
I can provide various data: the (gigantic) seemingly "corrupt" journal/timer files and the segfault messages from the syslog. I don't have any coredumps, but I'll turn those on today. Given the nature of the problem, it might take a while for it to manifest.
Chuck
Hello
How can I dump a zone stored in Knot DNS to a file?
DNSSEC signed zones are overwritten, apparently using a zone dump functionality; noticable by the comment ";; Zone dump (Knot DNS 2.6.3)".
Regards
Hi, just getting up to speedon knotDNS and trying to get dynamically
added secondaries working via bootstrapping.
My understanding is when the server receives a notify from an authorized
master, if it is not already in the zone like it will add it and AXFR
it, right?
In my conf:
acl:
- id: "acl_master"
address: "64.68.198.83"
address: "64.68.198.91"
action: "notify"
remote:
- id: "master"
address: "64.68.198.83@53"
address: "64.68.198.91@53"
But whenever I send NOTIFY from either of those masters, nothing happens
on the knotDNS side. I have my logging as:
log:
- target: "syslog"
any: "debug"
Thx
- mark
Hello,
I'm trying to use Knot 2.6.7 in a configuration where zone files are
preserved (including comments, ordering and formatting) yet at the same
time Knot performs DNSSEC signing – something similar to inline-signing
feature by BIND. My config file looks like this:
policy:
- id: ecdsa_fast
nsec3: on
ksk-shared: on
zsk-lifetime: 1h
ksk-lifetime: 5h
propagation-delay: 10s
rrsig-lifetime: 2h
rrsig-refresh: 1h
template:
- id: mastersign
file: "/etc/knot/%s.zone"
zonefile-sync: -1
zonefile-load: difference
journal-content: all
dnssec-signing: on
dnssec-policy: ecdsa_fast
serial-policy: unixtime
acl: acl_slave
zone:
- domain: "example.com."
template: mastersign
It seems to work well for the first run, I can see that zone got signed
properly:
>
> # kjournalprint /var/lib/knot/journal/ example.com
> ;; Zone-in-journal, serial: 1
> ;;Added
> example.com. 60 SOA knot.example.com. hostmaster.example.com. 1 3600 900 1814400 60
> example.com. 60 NS knot.example.com.
> first.example.com. 60 TXT "first"
> ;; Changes between zone versions: 1 -> 1529578258
> ;;Removed
> example.com. 60 SOA knot.example.com. hostmaster.example.com. 1 3600 900 1814400 60
> ;;Added
> example.com. 60 SOA knot.example.com. hostmaster.example.com. 1529578258 3600 900 1814400 60
> example.com. 0 CDNSKEY 257 3 13
> …lots of DNSSEC data.
However, if I try to update the unsigned zone file, strange things
happen. If I just add something to a zone and increase the serial, I get
these errors in the log:
>
> Jun 21 13:00:08 localhost knotd[2412]: warning: [example.com.] zone file changed, but SOA serial decreased
> Jun 21 13:00:08 localhost knotd[2412]: error: [example.com.] zone event 'load' failed (value is out of range)
If I set the serial to be higher than the serial of last signed zone, I
get a slightly different error:
>
> Jun 21 13:22:36 localhost knotd[3096]: warning: [example.com.] journal, discontinuity in changes history (1529580085 -> 1529580084), dropping older changesets
> Jun 21 13:22:36 localhost knotd[3096]: error: [example.com.] zone event 'load' failed (value is out of range)
In either case, when I look into the journal after the reload of the
zone, I see just the unsigned zone:
> # kjournalprint /var/lib/knot/journal/ example.com
> ;; Zone-in-journal, serial: 2
> ;;Added
> example.com. 60 SOA knot.example.com. hostmaster.example.com. 2 3600 900 1814400 60
> example.com. 60 NS knot.example.com.
> first.example.com. 60 TXT "first"
> second.example.com. 60 TXT "second"
Yet the server keeps serving the previous signed zone no matter what I
try. The only thing that help is a cold restart of Knot, when the zone
gets signed again.
So this approach is obviously not working as expected. If I comment out
option `zonefile-load: difference`, I get somehow working solution where
zone is completely resigned during each reload and I get this warning to
the log:
> Jun 21 13:27:38 localhost knotd[3156]: warning: [example.com.] with automatic DNSSEC signing and outgoing transfers enabled, 'zonefile-load: difference' should be set to avoid malformed IXFR after manual zone file update
I guess this should not bother me a lot as log as I keep serial numbers
of unsigned zones significantly different from signed ones. The only
problem is that this completely kills IXFR transfers as well as signing
only differences.
So far the only solution I see is to run two instances of Knot, one
reading the zone file from disk without signing, transferring it to
another instance which would do the signing is slave mode.
Is there anything I'm missing here?
Sorry for such a long e-mail and thank you for reading all the way here.
Best regards,
Ondřej Caletka
Hi!
One of our customers uses Knot 2.6.7 as hidden master which sends
NOTIFYs to our slave service. He reported that Knot can not send the
NOTIFYs, ie:
knotd[10808]: warning: [example.com.] notify, outgoing,
2a02:850:8::6@53: failed (connection reset)
It seems that Knot sometimes tries to send the NOTIFY with TCP (I see
also NOTIFYs via UDP). Unfortunatelly our NOTIFY-receiver only supports UDP.
So, this is the first time seeing a name server sending NOTIFYs over
TCP. Is this a typical behavior in Knot? Can I force Knot to send
NOTIFYs always over UDP?
Thanks
Klaus
Hello
I am using ecdsap256sha256 as algorithm. Why does the KSK DNSKEY (=257) use as digest type SHA1 (=1) and not SHA256 (=2)?
For example:
> dig DNSKEY nic.cz | grep 257
nic.cz. 871 IN DNSKEY 257 3 13 LM4zvjUgZi2XZKsYooDE0HFYGfWp242fKB+O8sLsuox8S6MJTowY8lBD jZD7JKbmaNot3+1H8zU9TrDzWmmHwQ==
> dig DNSKEY nic.cz | grep 257 > dnspub.key
> jdnssec-dstool dnspub.key
nic.cz. 868 IN DS 61281 13 1 091CECC4D2AADB7AC8C4DF413DDF9C5B0B61E5B6
Regards
dp
Hello all,
my Knot DNS is now in production and I would like to setup some
backup tasks for the configuration and of course keys. Are there any
recommendations regarding backup? And restore? I can see that it is very
easy to dump current config but I am to sure how to backup keys. What do
you recommend? Save the content of /var/lib/knot on a hourly/daily
basis? I am not using shared keys.
Thanks
With regards
Ales
Hi
I have a question about this commit
“01b00cc47efe”
Replace select() by poll()?
The performance of epoll is better then select/poll when monitoring large
numbers of file descriptions.
Could you please let me why you choose poll()?
Thanks for your reply!
