ComputerSurge/bind9
3
0
Fork 0
Code Pull Requests 1 Activity

Add stale-cache-enable option and disable serve-stable by default

Browse Source 
The current serve-stale implementation in BIND 9 stores all received
records in the cache for a max-stale-ttl interval (default 12 hours).

This allows DNS operators to turn the serve-stale answers in an event of
large authoritative DNS outage.  The caching of the stale answers needs
to be enabled before the outage happens or the feature would be
otherwise useless.

The negative consequence of the default setting is the inevitable
cache-bloat that happens for every and each DNS operator running named.

In this MR, a new configuration option `stale-cache-enable` is
introduced that allows the operators to selectively enable or disable
the serve-stale feature of BIND 9 based on their decision.

The newly introduced option has been disabled by default,
e.g. serve-stale is disabled in the default configuration and has to be
enabled if required.

(cherry picked from commit ce53db34d6)
This commit is contained in:
Ondřej Surý
2020-07-21 10:38:55 +02:00
committed by Matthijs Mekking
parent b1792f2ec5
commit b48e9ab201
16 changed files with 54 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
bin/tests/system/serve-stale/tests.sh
View File

@@ -862,7 +862,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
#
# Now test server with serve-stale disabled.
# Now test server with serve-stale answers disabled.
#
echo_i "test server with serve-stale disabled"
@@ -876,7 +876,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache longttl.example (serve-stale disabled) ($n)"
echo_i "prime cache longttl.example (serve-stale answers disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.4 longttl.example TXT > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
@@ -885,7 +885,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache data.example (serve-stale disabled) ($n)"
echo_i "prime cache data.example (serve-stale answers disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.4 data.example TXT > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
@@ -895,7 +895,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache othertype.example (serve-stale disabled) ($n)"
echo_i "prime cache othertype.example (serve-stale answers disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.4 othertype.example CAA > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
@@ -905,7 +905,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache nodata.example (serve-stale disabled) ($n)"
echo_i "prime cache nodata.example (serve-stale answers disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.4 nodata.example TXT > dig.out.test$n
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
@@ -915,7 +915,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "prime cache nxdomain.example (serve-stale disabled) ($n)"
echo_i "prime cache nxdomain.example (serve-stale answers disabled) ($n)"
ret=0
$DIG -p ${PORT} @10.53.0.4 nxdomain.example TXT > dig.out.test$n
grep "status: NXDOMAIN" dig.out.test$n > /dev/null || ret=1
@@ -925,7 +925,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "verify prime cache statistics (serve-stale disabled) ($n)"
echo_i "verify prime cache statistics (serve-stale answers disabled) ($n)"
ret=0
rm -f ns4/named.stats
$RNDCCMD 10.53.0.4 stats > /dev/null 2>&1
@@ -973,7 +973,7 @@ waitfile dig.out.test$((n+3))
waitfile dig.out.test$((n+4))
n=$((n+1))
echo_i "check fail of data.example (serve-stale disabled) ($n)"
echo_i "check fail of data.example (serve-stale answers disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
@@ -981,7 +981,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check fail of othertype.example (serve-stale disabled) ($n)"
echo_i "check fail of othertype.example (serve-stale answers disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
@@ -989,7 +989,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check fail of nodata.example (serve-stale disabled) ($n)"
echo_i "check fail of nodata.example (serve-stale answers disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
@@ -997,7 +997,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check fail of nxdomain.example (serve-stale disabled) ($n)"
echo_i "check fail of nxdomain.example (serve-stale answers disabled) ($n)"
ret=0
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
grep "ANSWER: 0," dig.out.test$n > /dev/null || ret=1
@@ -1005,7 +1005,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "verify stale cache statistics (serve-stale disabled) ($n)"
echo_i "verify stale cache statistics (serve-stale answers disabled) ($n)"
ret=0
rm -f ns4/named.stats
$RNDCCMD 10.53.0.4 stats > /dev/null 2>&1
@@ -1025,7 +1025,7 @@ if [ $ret != 0 ]; then echo_i "failed"; fi
# Dump the cache.
n=$((n+1))
echo_i "dump the cache (serve-stale disabled) ($n)"
echo_i "dump the cache (serve-stale answers disabled) ($n)"
ret=0
$RNDCCMD 10.53.0.4 dumpdb -cache > rndc.out.test$n 2>&1 || ret=1
done=0
@@ -1050,7 +1050,7 @@ LASTWEEK=`TZ=UTC perl -e 'my $now = time();
printf("%04d%02d%02d%02d%02d%02d", $y+1900, $mo+1, $d, $h, $m, $s);'`
n=$((n+1))
echo_i "mock the cache date to $LASTWEEK (serve-stale disabled) ($n)"
echo_i "mock the cache date to $LASTWEEK (serve-stale answers disabled) ($n)"
ret=0
sed -E "s/DATE [0-9]{14}/DATE $LASTWEEK/g" ns4/named_dump4.db > ns4/named_dumpdb4.db.out || ret=1
cp ns4/named_dumpdb4.db.out ns4/named_dumpdb4.db
@@ -1061,7 +1061,7 @@ echo_i "start ns4"
$PERL $SYSTEMTESTTOP/start.pl --noclean --restart --port ${PORT} serve-stale ns4
n=$((n+1))
echo_i "verify ancient cache statistics (serve-stale disabled) ($n)"
echo_i "verify ancient cache statistics (serve-stale answers disabled) ($n)"
ret=0
rm -f ns4/named.stats
$RNDCCMD 10.53.0.4 stats #> /dev/null 2>&1