In <AANLkTilWTJuol2MySad94PouqUt8ud65rGZqU1viZkaL at mail.gmail.com> Vernon Everett <everett.vernon at gmail.com> writes:
Tried another test, and set the server IP to 0.0.0.0 in bb-hosts, and it all went red again. :-(
It seems to resolve using nslookup on CLI, but not in bbtest.net Eventually added the --no-ares option, and all is good in our again.
Are you using a local DNS resolver, or a remote one ? Xymon tends to hit DNS servers pretty hard when starting all the network tests, so I strongly recommend using a local DNS cache.
It could be a bug in the C-ARES library, of course.
Henrik
Hi Henrik
Our DNS servers exist in Wintendo land. so I guess that's remote. I could set up a local DNS, but, because of the nature of this contract, and the way the support company works, I don't think I should. (We are setting up everything, and a remote services mob are going to be administering it all. Transition to remote services is supposed to happen in the next 2 months) It works with --no-ares, so I am not going to pursue it any further - unless I can assist in some way with debugging info. If there is benefit to be gained for the dev team, let me know you would like me to do.
Cheers Vernon
On Sun, Aug 1, 2010 at 11:50 PM, Henrik Størner <henrik at hswn.dk> wrote:
In <AANLkTilWTJuol2MySad94PouqUt8ud65rGZqU1viZkaL at mail.gmail.com> Vernon Everett <everett.vernon at gmail.com> writes:
Tried another test, and set the server IP to 0.0.0.0 in bb-hosts, and it all went red again. :-(
It seems to resolve using nslookup on CLI, but not in bbtest.net Eventually added the --no-ares option, and all is good in our again.
Are you using a local DNS resolver, or a remote one ? Xymon tends to hit DNS servers pretty hard when starting all the network tests, so I strongly recommend using a local DNS cache.
It could be a bug in the C-ARES library, of course.
Henrik
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On Sun, August 1, 2010 18:37, Vernon Everett wrote:
Hi Henrik
Our DNS servers exist in Wintendo land. so I guess that's remote. I could set up a local DNS, but, because of the nature of this contract, and the way the support company works, I don't think I should. (We are setting up everything, and a remote services mob are going to be administering it all. Transition to remote services is supposed to happen in the next 2 months) It works with --no-ares, so I am not going to pursue it any further - unless I can assist in some way with debugging info. If there is benefit to be gained for the dev team, let me know you would like me to do.
Vernon,
You're the best judge of what's appropriate vis-a-vis your contract and support channels, but if there's any cordiality there, you might touch base with them on setting up a caching-only named on your Xymon server. You'd be greatly decreasing somewhat gratuitous hits on their servers, and they might welcome it. You probably know that it's a very simple setup.
regards, j.
I will have a chat. There is a very cordial relationship, but politics, as always, makes it.....interesting. I am not going to go into any further detail in an open forum. :-)
Before I have my chat though, I need to be armed with more info. Using little words, and sock-puppets (if required), can you explain exactly what the ares doo-hicky actually does? What happens differently when we run Xymon with and without the --no-ares?
Cheers Vernon
On Mon, Aug 2, 2010 at 7:44 AM, Xymon User in Richmond < hobbit at epperson.homelinux.net> wrote:
On Sun, August 1, 2010 18:37, Vernon Everett wrote:
Hi Henrik
Our DNS servers exist in Wintendo land. so I guess that's remote. I could set up a local DNS, but, because of the nature of this contract, and the way the support company works, I don't think I should. (We are setting up everything, and a remote services mob are going to be administering it all. Transition to remote services is supposed to happen in the next 2 months) It works with --no-ares, so I am not going to pursue it any further - unless I can assist in some way with debugging info. If there is benefit to be gained for the dev team, let me know you would like me to do.
Vernon,
You're the best judge of what's appropriate vis-a-vis your contract and support channels, but if there's any cordiality there, you might touch base with them on setting up a caching-only named on your Xymon server. You'd be greatly decreasing somewhat gratuitous hits on their servers, and they might welcome it. You probably know that it's a very simple setup.
regards, j.
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On Sun, August 1, 2010 21:41, Vernon Everett wrote:
I will have a chat. There is a very cordial relationship, but politics, as always, makes it.....interesting. I am not going to go into any further detail in an open forum. :-)
Before I have my chat though, I need to be armed with more info. Using little words, and sock-puppets (if required), can you explain exactly what the ares doo-hicky actually does? What happens differently when we run Xymon with and without the --no-ares?
You may get better answers from folks familiar with the actual code, but my take is that with --no-ares Xymon uses the threaded, synchronous system resolver library, which would tend to choke down the rate of hits against whatever DNS servers are used (and slow down the loop through bb-hosts), compared to ares.
With a caching local DNS server, you'd be optimizing the use of the hits against the "real" DNS servers, not repeating a lookup until the TTL has run on the last real lookup of the hostname. This would tend to mitigate the hammering from using the ares resolver functions.
Again, that's my take. Wait and see if anyone says I'm horribly wrong before taking that into a meeting.
participants (3)
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everett.vernon＠gmail.com
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henrik＠hswn.dk
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hobbit＠epperson.homelinux.net