cloudstack-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Indra Pramana <in...@sg.or.id>
Subject Re: DNS service on VR not responding
Date Sun, 20 Jul 2014 17:33:58 GMT
Hi Rafael,

Good day to you, and thank you for your reply.

1. Yes, the guest VMs can reach the VR. Able to ping.

64 bytes from X.X.X.2: icmp_req=4 ttl=64 time=2.00 ms
64 bytes from X.X.X.2: icmp_req=5 ttl=64 time=0.291 ms
64 bytes from X.X.X.2: icmp_req=6 ttl=64 time=0.384 ms
^C
--- X.X.X.2 ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 4999ms
rtt min/avg/max/mdev = 0.270/0.603/2.006/0.628 ms

2. Yes, the VMs are really configured to use VR as the DNS server,
according to /etc/resolv.conf, together with 8.8.8.8 and 8.8.4.4

/etc/resolv.conf on guest VMs:

===
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by
resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver X.X.X.2 (the VR's IP)
nameserver 8.8.8.8
nameserver 8.8.4.4
search cs1cloud.internal
===

3. Yes, if I remove or comment out the first nameserver entry for the VR's
IP, and only leaving 8.8.8.8 and 8.8.4.4, guest VMs will be running fine
and will be able to resolve domains properly.

4. May I know how to enable the dnsmasq debug? Any documentation / steps on
how to do it? I believe I have to do it on the VR itself?

Looking forward to your reply, thank you.

Cheers.




On Mon, Jul 21, 2014 at 1:17 AM, Rafael Weingartner <
rafaelweingartner@gmail.com> wrote:

> Good day to you too,
> Sure I guess I point a way, so you can start troubleshooting.
>
>
>    1. Check if the VMs can reach the VR.
>    2. Check if the VMs are really configured to use VR as the DNS server.
>    3. Change the DNS server to be any other such as 8.8.8.8 and 8.8.4.4
>    (just to see if there is nothing blocking the way), the name resolution
>    should work with those servers.
>    4. Enable the dnsmasq debug, and try to see if something interesting
>    appears in dnsmasq.log.
>
>
>
>
> On Sun, Jul 20, 2014 at 2:06 PM, Indra Pramana <indra@sg.or.id> wrote:
>
> > Hi Rafael,
> >
> > Good day to you, and thank you for your reply.
> >
> > Can't find anything wrong on dnsmasq.log / daemon.log, just some log
> > entries related to DHCP, nothing on DNS. I masked the IP addresses since
> > they are public.
> >
> > ===
> > Jul 20 16:21:51 r-2606-VM dnsmasq[3519]: DHCPDISCOVER(eth0) X.X.X.X
> > 06:62:a8:01:13:37
> > Jul 20 16:21:51 r-2606-VM dnsmasq[3519]: DHCPOFFER(eth0) X.X.X.X
> > 06:62:a8:01:13:37
> > Jul 20 16:21:51 r-2606-VM dnsmasq[3519]: DHCPREQUEST(eth0) X.X.X.X
> > 06:62:a8:01:13:37
> > Jul 20 16:21:51 r-2606-VM dnsmasq[3519]: DHCPACK(eth0) X.X.X.X
> > 06:62:a8:01:13:37 yyyyyy
> > Jul 20 16:23:53 r-2606-VM dnsmasq[3519]: DHCPINFORM(eth0) X.X.X.X
> > 06:43:4a:01:12:65
> > Jul 20 16:23:53 r-2606-VM dnsmasq[3519]: DHCPACK(eth0) X.X.X.X
> > 06:43:4a:01:12:65 zzzzzz
> > ===
> >
> > Yes, the guest VMs are having difficulties resolving domains into IP
> > addresses because of the problem on the VR's DNS server.
> >
> > $ host www.google.com X.X.X.X (where X.X.X.X is the IP address of the
> VR)
> > ;; connection timed out; no servers could be reached
> >
> > However, from within the VR, I am able to resolve domains just fine.
> >
> > Any advise where can I start troubleshooting this?
> >
> > Looking forward to your reply, thank you.
> >
> > Cheers.
> >
> >
> >
> > On Sun, Jul 20, 2014 at 11:26 PM, Rafael Weingartner <
> > rafaelweingartner@gmail.com> wrote:
> >
> > > Have you taken a look at dnsmasq.log in the VR ?
> > > What do you mean with not responding? The addresses are not being
> > resolved
> > > to ip addresses?
> > >
> > >
> > > On Sun, Jul 20, 2014 at 11:53 AM, Indra Pramana <indra@sg.or.id>
> wrote:
> > >
> > > > Dear all,
> > > >
> > > > All our guest VMs are having our virtual router (VR)'s IP address on
> > > > /etc/resolv.conf. In the past two weeks, I just realised that the DNS
> > > > service on the VR is not working, and doesn't respond to DNS queries
> > from
> > > > the DNS clients on the guest VM.
> > > >
> > > > I have tried to stop and start back the VR, but the problem persists.
> > > >
> > > > DHCP services seems to be running fine, only DNS services are not
> > > working.
> > > > From what I understand, both services are provided by dnsmasq,
> correct?
> > > >
> > > > Any advice on how can I resolve the problem?
> > > >
> > > > Looking forward to your reply, thank you.
> > > >
> > > > Cheers.
> > > >
> > >
> > >
> > >
> > > --
> > > Rafael Weingärtner
> > >
> >
>
>
>
> --
> Rafael Weingärtner
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message