Unbound seems to be restarting frequently
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Actually all the code to dump/restore cache is there. Just the checkbox to enable the dumpcache var went AWOL. This was there with the 2.1 package.
https://github.com/pfsense/pfsense-packages/blob/master/config/unbound/unbound.xml#L179
EDIT: Filed a bug about the missing cache save/restore - https://redmine.pfsense.org/issues/4667
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I saw the code in unbound.inc, that handles the dump_cache and load_cache.
It might be the solution.
So I activated the 'dump_cache' facilities, so that before a 'reload', the cache was dumped.Have a look at this:
function unbound_control($action) { global $config, $g; $cache_dumpfile = "/var/tmp/unbound_cache"; switch ($action) { case "start": ..... case "stop": ..... case "reload": ..... case "dump_cache": // Dump Unbound's Cache if ($config['unbound']['dumpcache'] == "on") do_as_unbound_user("dump_cache"); break; case "restore_cache": // Restore Unbound's Cache if ((is_service_running("unbound")) && ($config['unbound']['dumpcache'] == "on")) { if (file_exists($cache_dumpfile) && filesize($cache_dumpfile) > 0) do_as_unbound_user("load_cache < /var/tmp/unbound_cache"); } break; default: break; } }Be carefully : $config['unbound']['dumpcache'] isn't defined neither declared in the GUI.
And doing something like this: do_as_unbound_user("load_cache < /var/tmp/unbound_cache");
will not work. The function do_as_unbound_user() works not that way.
Anyway, I had my unbound cache being dumped before restart.And then I started to think … after reading this:
load_cache The contents of the cache is loaded from stdin. Uses the same format as dump_cache uses. Loading the cache with old, or wrong data can result in old or wrong data returned to clients. Load- ing data into the cache in this way is supported in order to aid with debugging.Consider the situation: unbound starts, and read all the files its need, like /var/etc/hosts, the DHCP leases file, etc.
Then we instruct it to load the cache file, /var/tmp/unbound_cache
It doesn't take long to discover that the internal working cache (with the new local info) in unbound is being replaced by what has been written in /var/tmp/unbound_cache.
F*ck.
Doing so makes it completely useless to restart unbound to begin with …... >:(
As said in the doc: dump_cache and load_cache exists for debugging purposes.Leaves me with one idea: ditch unbound, even if it is the most secured name server, and make friends with bind...... (one of the most used name server on the planet !?!), which, I'm pretty sure, doesn't 'work' like this.
edit: hopping through the unbound source code make me think: it 'reloads' when reading in a cache file …. :o
Well ..... -
Yeah I had a look at the source code and I have hard time understanding the design. Also, the "reload" which is something presumed to be graceful in the rest of the world is pretty much equal to restart and disrupts the service. Unless this gets fixed quickly upstream, I frankly would suggest removing the DHCP registration features from the DNS Resolver GUI altogether. With this broken design, it is not usable.
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It seems to work ok IF you are using static DHCP entries for the clients, like I do.
Of course this isn't possible if you are providing DHCP for a mall full of wireless clients.
But then again, why the hell would you want a mall full of wireless clients registered in DNS?
So maybe register the static entries but not the dynamic entries.
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I saw host entries can be removed with unbound-control at runtime w/o restarting the service. But I can't see an option to add a host using unbound-control. If that is possible this could eliminate the issues when using DHCP.
I'm registering ALL my leases at a Windows Server DNS Service (since there is an AD running on it). So even DHCP is not updating the local DNS it still keeps restarting it. So I'm using unbound only for Internet DNS loolup really but everything locally is done by Microsoft DNS service. So definitely no need for restarting anything since hosts file will never change.
Well, "…keeps restarting..." is wrong in fact, "...kept restarting..." is correct in my case since I removed the ability to restart unbound from the code a couple of days ago (which I posted here). Even it's a very dirty workaround it works perfect so far without any adverse effects for my usage. Couldn't be happier that I've done that.
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Is there any progress to this issue?
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yeah hoping myself that this is fixed, and soon. I don't have any dns mappings done in DHCP (do have some statics), but I keep gettign the restart issue every flippin time a phone is turned on and connects. It's getting old fast.
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In its current implementation, unbound is unusable for me. The restarts are causing the cache to clear so I've had to use forwarder to make everything work.
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It's clearly happening to very many users but is it already acknowledged as a real "issue"? No pun intended.
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It's clearly happening to very many users but is it already acknowledged as a real "issue"? No pun intended.
Perhaps take this to upstream mailing list? As discussed many times above, there's no graceful reload anywhere, the code is braindead.
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Just want to mention that my "solution" https://forum.pfsense.org/index.php?topic=89589.msg517047#msg517047 is working great on 6 production systems. :)
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It's clearly happening to very many users but is it already acknowledged as a real "issue"? No pun intended.
Perhaps take this to upstream mailing list? As discussed many times above, there's no graceful reload anywhere, the code is braindead.
That's what I was planning on doing post-2.2.4. I dug into it a few days ago looking at something else to find basically what's been discussed previously. Sending it a -HUP is a full stop/start rather than a reload, and same for unbound-control reload. There is no way to just reload the config without doing a full stop/start. It is certainly braindead.
Anyone else is welcome to report upstream, just please post back a link to the thread here.
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How many people having this issue are using a config that used to use the forwarder rather than the resolver? And how many of those people still have the top 3 DHCP options checked in the forwarder, even though the forwarder is disabled?
If this is the case, humor me here… go to the DNS forwarder page, check the top enable box to enable access to the 3 DHCP options boxes below it, uncheck all 3 DHCP options boxes, then uncheck the top enable box (so we don't unwantingly enable the forwarder), click the save button, verify that all 3 DHCP options boxes for the forwarder are now unchecked and disabled once the page reloads, and reboot pfSense for sanity.
Please post back as to what effect this has on Unbound reloads… either the same, less frequently, or eliminates them all together.
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I have the same problem with unbound constantly reloading and having no DNS resolution for about 30 seconds every few minutes. I did have both the dynamic and static DHCP clients options ticked for DNS but I disabled them both and it didn't fix it. I have come to the conclusion that unbound is so broken that I've had to switch back to dnsmasq and now it's all working fine. I was using forwarding in unbound anyway (I am running multi-WAN with failover), so it doesn't really bother me having to switch.
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How many people having this issue are using a config that used to use the forwarder rather than the resolver?
…
Please post back as to what effect this has on Unbound reloads... either the same, less frequently, or eliminates them all together.I sure hope it eliminates them altogether. I have noticed (and came looking, and found this thread) that it NEVER runs more than an hour at a time, and that can't help cache performance one stinking bit. Sometimes it does appear to get down to 30 minutes or even a minute or two (without settings changes going on.) But absolutely never more than an hour. Not so peachy.
Got it rebooted, we'll see.
That would be "Nope, didn't help a bit." Well, I guess it did get just over 4 hours in one place there. But mostly no help.
Oct 16 08:49:49 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 08:49:48 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 07:49:21 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 07:49:21 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:48:58 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:48:58 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:47:45 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:47:45 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:35:23 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:35:23 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:30:07 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:30:07 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:26:31 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:26:31 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:24:05 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:24:05 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:22:25 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:22:25 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:21:29 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:21:29 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:20:58 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:20:58 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:19:57 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:19:56 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:12:45 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:12:45 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:11:16 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:11:16 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:09:50 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:09:50 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:07:16 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:07:16 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:01:39 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:01:39 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:01:02 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:01:02 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:00:36 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:00:35 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 06:00:34 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 06:00:34 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 05:59:10 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 05:59:10 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 05:59:04 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 05:59:04 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 05:52:44 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 05:52:44 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 05:52:24 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 05:52:24 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 05:51:53 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 05:51:53 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 05:50:09 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 05:50:09 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 05:49:59 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 05:49:59 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 05:49:15 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 05:49:15 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 05:48:56 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 05:48:55 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 05:47:53 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 05:47:53 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 04:43:13 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 04:43:13 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 03:41:43 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 03:41:43 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 03:41:42 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 03:41:42 unbound: [69305:0] info: service stopped (unbound 1.5.3). Oct 16 03:41:41 unbound: [69305:0] info: start of service (unbound 1.5.3). Oct 16 03:41:40 unbound: [22642:0] info: service stopped (unbound 1.5.3). Oct 16 03:41:00 unbound: [22642:0] info: start of service (unbound 1.5.3). Oct 16 03:41:00 unbound: [22642:0] info: service stopped (unbound 1.5.3). Oct 16 03:40:59 unbound: [22642:0] info: start of service (unbound 1.5.3). Oct 16 03:40:59 unbound: [22642:0] info: service stopped (unbound 1.5.3). Oct 16 03:40:58 unbound: [22642:0] info: start of service (unbound 1.5.3). Oct 16 03:40:58 unbound: [22642:0] info: service stopped (unbound 1.5.3). Oct 16 03:40:57 unbound: [22642:0] info: start of service (unbound 1.5.3). Oct 16 03:40:57 unbound: [22642:0] info: service stopped (unbound 1.5.3). Oct 16 03:40:57 unbound: [22642:0] info: start of service (unbound 1.5.3). Oct 15 23:33:46 unbound: [35431:0] info: start of service (unbound 1.5.3). Oct 15 23:33:46 unbound: [35431:0] info: service stopped (unbound 1.5.3). Oct 15 23:33:46 unbound: [35431:0] info: start of service (unbound 1.5.3). Oct 15 23:33:46 unbound: [35431:0] info: service stopped (unbound 1.5.3). Oct 15 23:33:46 unbound: [35431:0] info: start of service (unbound 1.5.3). Oct 15 23:33:46 unbound: [15076:0] info: service stopped (unbound 1.5.3). Oct 15 23:33:41 unbound: [15076:0] info: start of service (unbound 1.5.3).Having a boatload of resources free because I can't run traffic shaping and transparent squid since 2.1.x, I cranked all the settings in the resolver to maximum (they were already bumped up quite a bit from defaults) though I doubt it will have any effect. But what the heck…
So with all the settings cranked we got - an hour and 17 seconds.
Oct 16 10:47:34 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 09:47:17 unbound: [63283:0] info: start of service (unbound 1.5.3).…and then things went downhill.
Oct 16 12:03:38 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 12:03:38 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 12:03:20 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 12:03:20 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 12:02:08 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 12:02:08 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 12:01:26 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 12:01:26 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 11:59:31 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 11:59:31 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 11:58:50 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 11:58:50 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 11:56:58 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 11:56:58 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 11:56:30 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 11:56:30 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 11:52:29 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 11:52:29 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 11:51:46 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 11:51:45 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 11:50:39 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 11:50:39 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 11:49:04 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 11:49:03 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 11:48:37 unbound: [63283:0] info: start of service (unbound 1.5.3). Oct 16 11:48:37 unbound: [63283:0] info: service stopped (unbound 1.5.3). Oct 16 10:47:34 unbound: [63283:0] info: start of service (unbound 1.5.3).Back to dnsMasq for now. Perhaps I'll try unbound on a separate server at some point, clearly there are issues with the package that degrade its potential usefulness.
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On my hardware at least, this stops Unbound from restarting until a config change is made to DHCP. When the DHCP config change is applied, Unbound gets restarted, and then starts doing the same old restart every hour or less deal, until the pfSense box is rebooted. On a fresh reboot with no config changes Unbound has run for about 15 days without restarting (longest I've gone without a config change lately).
The issue is not in the package, it's in the scripts controlling it. The way the scripts are written now, they insert data into Unbound's config files, then restart the service for Unbound to reload those config files and pull in the changes. Dnsmasq is handled the same way, except it will hold its cache and re-read config files upon getting a SIGHUP.
The right way to handle local DNS changes, for Unbound at least, would basically be to do the opposite of what is being done now. Rather than write to the config files and bounce the service, you would use unbound-control to tell Unbound about the new local DNS changes and let it write the config files.
The code is almost completely written already, all that needs to be done is for someone that knows what to change and has the time to change it, to go through all the Unbound functions and replace config file writes with unbound-control command calls that use almost identical syntax. For example, instead of writing local-data-ptr to a file like this and bouncing the service (how it's done now):
$unbound_entries .= "local-data: \"{$host['fqdn']} {$type} {$host['ipaddr']}\"\n";You would do something like this and not ever restart the service:
$unbound_cmd .= "unbound-control local_data {$host['fqdn']} {$type} {$host['ipaddr']}";Same thing with removing local DNS entries, every unbound-control add command has a corresponding remove command, local_data_remove for this example.
If Unbound doesn't write the entries to the config files in case of a user forced service stop / restart, then the code in use now is already maintaining consistency in the config files. Or you could simply re-add all the local DNS records with unbound-control calls on service start. Either way would work fine.
If memory serves, this was a lot of the reasoning behind using Unbound over Dnsmasq. Because Dnsmasq has nothing like unbound-control to insert and remove DNS records, and even make live config changes, without doing a full config reload / service restart. Why this was not carried over to implementation is beyond me. Ask the man upstairs.
Also, clearly, some functions are being called in the wrong place, and this needs to be cleaned up as well. The DHCP register check boxes on the forwarder page should have no effect on the resolver what so ever, but it appears they absolutely do, as noted above. Also, the same DHCP register check boxes on the resolver page seem to only write these items to the Unbound config files without restarting the service, which is only half right the way it is currently implemented (you would expect a service restart to follow). This all needs to be changed to use unbound-control anyways, but should be noted on the fix Unbound to do list with everything else.
Thank you and good night :D
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The issue is not in the package, it's in the scripts controlling it. The way the scripts are written now, they insert data into Unbound's config files, then restart the service for Unbound to reload those config files and pull in the changes. Dnsmasq is handled the same way, except it will hold its cache and re-read config files upon getting a SIGHUP.
The right way to handle local DNS changes, for Unbound at least, would basically be to do the opposite of what is being done now. Rather than write to the config files and bounce the service, you would use unbound-control to tell Unbound about the new local DNS changes and let it write the config files.
Whilst this sounds promising, have you code read unbound to check what unbound-control local_data and unbound-control local_data_remove actually do? If these commands force a cache flush, then there is no gain and potential losses in your proposed approach. If unbound uses a cache walk to discard affected RR(s), a different potential performance issue arises if this process is blocking, especially if unbound is started with no local RRs and they are added one at a time using unbound-control. If cache discard takes place via a non-blocking cache walk or no cached RR removal takes place, the possibility of race conditions exists, as stale RR data will be served for an indeterminate but potentially significant time.
Rather than using unbound-control to insert all RRs on startup, a hybrid approach is possible - start unbound with the current state in the configuration files, then use unbound-control for subsequent changes.
One complexity in implementing your proposed approach is a frustrating non-orthogonality in the local_data and local_data_remove commands. local_data adds a single RR. local_data_remove removes all RRs for the given name - which might include both A and AAAA records for the same name (and, if local_data_remove for PTR records is called by the name rather than the IP address, this means IPv4 and/or IPv6 PTR records pointing to that name will also be removed). IPv4 and IPv6 address allocation use entirely separate processes that have no guarantees on temporal relationship. There are circumstances where you might want to remove just one RR, which means you have to remove all RRs for the name then re-add any wanted RRs.
If there are advantages to using unbound-control, it might be better to add support for unbound control to pfSense by generating a new unbound configuration as at present, then diffing it with the old configuration. If there are changes solely in local data (i.e. in dhcpleases_entries.conf and/or host_entries.conf), pfSense could use the output of the diff to make appropriate calls to unbound-control, otherwise replace the old configuration with the new and send unbound a SIGHUP. This approach has the advantage of ensuring consistency (for example by ensuring explicitly configured local-data is not accidentally removed) and is easily removed if unbound gets saner SIGHUP behaviour in the future. One implementational complexity is the need to call unbound-control local_data for any explicit local-data and local-data-ptr in unbound.conf after you call unbound-control local_data_remove for the same name.
Another possibility is to use an entirely separate DNS server for local zone(s), defining them in Unbound as stub zones. There is potential advantage here in terms of being able to DNSSEC sign these zones. However, when data changes, stale data would be cached in Unbound that would require carefully targeted calls to unbound-control flush_type or a costly (because of the cache walk) unbound-control flush_zone to remove.
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The issue is not in the package, it's in the scripts controlling it. The way the scripts are written now, they insert data into Unbound's config files, then restart the service for Unbound to reload those config files and pull in the changes. Dnsmasq is handled the same way, except it will hold its cache and re-read config files upon getting a SIGHUP.
The right way to handle local DNS changes, for Unbound at least, would basically be to do the opposite of what is being done now. Rather than write to the config files and bounce the service, you would use unbound-control to tell Unbound about the new local DNS changes and let it write the config files.
Whilst this sounds promising, have you code read unbound to check what unbound-control local_data and unbound-control local_data_remove actually do? If these commands force a cache flush, then there is no gain and potential losses in your proposed approach. If unbound uses a cache walk to discard affected RR(s), a different potential performance issue arises if this process is blocking, especially if unbound is started with no local RRs and they are added one at a time using unbound-control. If cache discard takes place via a non-blocking cache walk or no cached RR removal takes place, the possibility of race conditions exists, as stale RR data will be served for an indeterminate but potentially significant time.
Answers to all of your questions are in plain text here:
https://www.unbound.net/documentation/unbound-control.htmlNo, but the fact that local add / remove commands only process local data space makes it pretty clear.
No race condition exists. Simply process 1 unbound-control command at a time. unbound-control returns completion. At the rate they execute I would guess even with lots of local custom entries (say 200+), which even the documentation states not to use Unbound on its own as a full hosted DNS solution, this would happen very quickly. Since it would only happen on service start, the impact would be even more who gives a fuck sort of minimal. Ditto for local removals. Cap it off with the "well what if 500+ DHCP client releases happen at the end of the day" answer of "if your pfSense hardware can handle serving 500+ clients all day, it can easily handle removing 500+ local DNS entries quickly".
Rather than using unbound-control to insert all RRs on startup, a hybrid approach is possible - start unbound with the current state in the configuration files, then use unbound-control for subsequent changes.
Yup, I gave that as 1 of 2 possible ways to go.
One complexity in implementing your proposed approach is a frustrating non-orthogonality in the local_data and local_data_remove commands. local_data adds a single RR. local_data_remove removes all RRs for the given name - which might include both A and AAAA records for the same name (and, if local_data_remove for PTR records is called by the name rather than the IP address, this means IPv4 and/or IPv6 PTR records pointing to that name will also be removed). IPv4 and IPv6 address allocation use entirely separate processes that have no guarantees on temporal relationship. There are circumstances where you might want to remove just one RR, which means you have to remove all RRs for the name then re-add any wanted RRs.
Since we are only dealing with local FQDN and localHost.localDomain records, also a non issue. If there are multiple records pointing to the same FQDN / localHost.localDomain and a DHCP event causes them to need removal, now we only need to issue a single unbound-control remove command. If that breaks ANYTHING local DNS wise (it won't), than very very worst case scenario, we continue to bounce the service only on custom static override changes (please don't do this).
If there are advantages to using unbound-control, it might be better to add support for unbound control to pfSense by generating a new unbound configuration as at present, then diffing it with the old configuration. If there are changes solely in local data (i.e. in dhcpleases_entries.conf and/or host_entries.conf), pfSense could use the output of the diff to make appropriate calls to unbound-control, otherwise replace the old configuration with the new and send unbound a SIGHUP. This approach has the advantage of ensuring consistency (for example by ensuring explicitly configured local-data is not accidentally removed) and is easily removed if unbound gets saner SIGHUP behaviour in the future. One implementational complexity is the need to call unbound-control local_data for any explicit local-data and local-data-ptr in unbound.conf after you call unbound-control local_data_remove for the same name.
Yes, to the "somebody with the time needs to test this", I would agree with my own previous post.
No to the rest. You're over thinking it now. Forget SIGHUP for Unbound. Consistency is already being maintained in config files by current code. We need to dump the service restart bullshit, or dump Unbound. Love it or leave it. It will never work correctly if you aren't smart enough to maintain local records without bouncing the service or dumping the non-local cache needlessly.
Another possibility is to use an entirely separate DNS server for local zone(s), defining them in Unbound as stub zones. There is potential advantage here in terms of being able to DNSSEC sign these zones. However, when data changes, stale data would be cached in Unbound that would require carefully targeted calls to unbound-control flush_type or a costly (because of the cache walk) unbound-control flush_zone to remove.
I thought about that, so have others, and some have implemented it, it's not hard with current RELEASE stock packages. Use dnsmasq for local DNS, add domain overrides to Unbound to point to dnsmasq's local custom port. Domain overrides bypass Unbound's cache, so removing stale entries is a non-issue. The issue here is that it is not the right solution. It's an unnecessary workaround at best, and that's not what anyone wants to see time spent on. We would rather see time spent on correct implementation.
For the same reason, completely forget about commands issuing full cache walks too. Even on fast hardware, churning through a potential 1GB of tables, even in RAM, is just stupid when you have the option of not ever doing that.
Edit: Added considerations for pfSense hardware capacity & localHost.localDomain scenario. No methods changed.
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Is it just me who's finding similar masturbation absurd? Why not fix the braindead SIGHUP handling instead?
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Because if you had thought it through you would realize there's nothing to fix as far as Unbound itself goes. The design of Unbound is to not need absurd (old) things like custom SIGHUP handling because it has something far more versatile, unbound-control.
unbound-control is Unbound's SIGHUP replacement, just infinitely more useful, since you can feed it parameters and get success / failure returns. Far more securely and gracefully at that.
RTFM my friend.
To repeat again, and again, Unbound was picked for this reason. If the devs now regret that decision because they are stuck on using replaced for a good reason functions like throwing SIGHUP's all over the place, they should pick something older and worse than Unbound as the resolver.
And that would be sad, because Unbound is a GREAT caching DNS resolver when you use it correctly.
