New Build - Changed Network - DNS not working

I built an unRAID box for a friend this weekend and set it up, etc. including docker apps: Sabnzbd, Couch Potato, Sonarr and Plex

When I had it at my house, everything worked fine.  When I moved it to his house (his network) all of the apps stopped resolving DNS.  In Network config, with everything set to Auto, there is internet connectivity and I can ping out from the Tower to IP's but not hostnames and the apps can access the internet if I replace URL's with IP's.  If I manually set DNS to 8.8.8.8 then I can ping hostnames from command prompt, but the docker apps still cannot resolve any DNS.  Not sure what to do here.  Any help appreciated.

syslog.zip

I would expect you to have to specify your local DNS (probably your router) to be able to resolve local names in addition to the external one you have used.  In fact very often that is the only one you have to specify as the local DNS knows how to contact external DNS's for names it cannot resolve.  Having said that explicitly specifying an external DNS that is not managed by your ISP is often a good idea.

I tried specifying the gateway (router) as DNS server, the ISP DNS servers the router uses as well as 8.8.8.8, 8.8.4.4 and none of the above resolved the issue.

Can pull down additional dockers from the WebGui, the Dockers themselves appear to be unable to resolve DNS.

Changed docker connection to host, updated config, then back to bridge and it fixed it.

--edit--

Rebooted and the same issue presented itself.

Based on this thread.

It seems you might be having the same problem, and that this should be fixed with Docker 1.6 which is planned to be included in the next release of unRAID.

Currently set docker apps to host as opposed to bridge mode.  This resolve the issue for DNS, but the download speed is peaking at 5% of my bandwidth.  Cannot get over 1.1 MB/s on a 150mbps connection.

Edit--

On the network at my house with 100mbps internet i constantly achieved 12-13MB/s downloads with this box and minimal CPU impact.

Based on this thread.

 

It seems you might be having the same problem, and that this should be fixed with Docker 1.6 which is planned to be included in the next release of unRAID.

Does it?

There's already someone reporting DNS issue in one of their docker right after they upgraded to v6rc2.

I'm still looking into things but I may also be seeing this issue with RC2.

Based on this thread.

 

It seems you might be having the same problem, and that this should be fixed with Docker 1.6 which is planned to be included in the next release of unRAID.

 

Does it?

There's already someone reporting DNS issue in one of their docker right after they upgraded to v6rc2.

Maybe it's not fixed, or maybe it's not the same problem... not sure at this point.

I'm still experiencing the ns lookup issue on rc2 too.

The temporary fix is still the same: switch the networking to host then back to bridge.

So at the moment I am doing a lot o to-ing and fro-ing between beta15 and RC2 as I'm trying to update my bzimage and bzroot files to include DVB support.

I think the error starts by switching between beta15 and RC2 and their respective docker versions.

Rebooting doesn't seem to fix the issue but editing the container and just clicking save withut changing anything (like bridge - host -bridge) fixes it for me.

So at the moment I am doing a lot o to-ing and fro-ing between beta15 and RC2 as I'm trying to update my bzimage and bzroot files to include DVB support.

 

I think the error starts by switching between beta15 and RC2 and their respective docker versions.

 

Rebooting doesn't seem to fix the issue but editing the container and just clicking save withut changing anything (like bridge - host -bridge) fixes it for me.

We're still looking in to this.  In the meantime, try adding --dns=8.8.8.8 in to the first line in /boot/config/docker.cfg like so:

DOCKER_OPTS="--storage-driver=btrfs --dns=8.8.8.8"

Save /boot/config/docker.cfg.  Either reboot or disable/re-enable docker for the new settings to take effect.

Does that help and eliminate the need to change container bridge mode to restore networking?

So at the moment I am doing a lot o to-ing and fro-ing between beta15 and RC2 as I'm trying to update my bzimage and bzroot files to include DVB support.

 

I think the error starts by switching between beta15 and RC2 and their respective docker versions.

 

Rebooting doesn't seem to fix the issue but editing the container and just clicking save withut changing anything (like bridge - host -bridge) fixes it for me.

 

We're still looking in to this.  In the meantime, try adding --dns=8.8.8.8 in to the first line in /boot/config/docker.cfg like so:

 

DOCKER_OPTS="--storage-driver=btrfs --dns=8.8.8.8"

 

Save /boot/config/docker.cfg.  Either reboot or disable/re-enable docker for the new settings to take effect.

 

Does that help and eliminate the need to change container bridge mode to restore networking?

At the moment it all seems to be working, it's difficult for me to say what causes it, but it's related to switching between Unraid versions I think.  However have updated from RC2 to RC3 today with no issues (although RC2 was working at the point of reboot)  I think it was switching back and forth between beta15 and RC that causes the problem.  For me however it seems to resolve by editing the container, not changing anything and just clicking save triggering a rebuild.

Sorry I can't be more help Eric, but if I encounter it again then I'll be sure to try out your suggestion and post back.

If you want me to try any of the above switches then let me know and I'll do it.

 

...

...For me however it seems to resolve by editing the container, not changing anything and just clicking save triggering a rebuild.

 

Yes,

This was all I have had to do as well. I was applying this edit/save approach while in RC1 and still have to do it for each docker container in RC2. I won't be able to update to RC3 for a few days yet, and also am not able to reboot either until then, so I won't be able to perform any additional tests.

cheers,

gwl