linode VPS upgrade from debian 4.0 to 5.0

Finally took the plunge. Upgraded out linode VPS from debian 4.0 to 5.0

Apart from an inital hiccup, it seems fine. Upgrade complete. Unfortunately I had to shutdown the VPS instance to increase a big of diskspace onto the root, so that the dist-upgrade had enough disk space.

In other news, had a bit of a funny issue today at work. It was related to domain name resolution, and oddly enough another solution to the issue popped into my head just a while ago. It’s funny how this happens to us IT folk.

Basically it looked like a host lookup was failing and we thought maybe the host record is missing from the internal dcs, while it exists in the management host we have. As everything works for the customer when the host is using dns from our management servers, but soon as we use the customer primary dns it seems to fail. First thought posible record missing, however then it dawned on me that it could be related to the resolv.conf on the host.

Going from memory I think the resolv.conf is the issue. I remember it containing the following options;

domain blah.blah.com
nameserver w.x.y.z
#nameserver a.b.c.d
search blah.blah.com
search blah2.blah.com

And if the above holds true, I think I know why. The host record exists both in blah.blah.com and in blah2.blah.com. However, nameserver w.x.y.z only serves blah.blah.com, and nameserver a.b.c.d only serves blah2.blah.com. From my understanding of the man pages for resolv.conf, it looks like you shouldn’t use search/domain together, and if you do then only the last instance of search is ever used, which in this case means everytime we try to lookup host.blah2.blah.com with the primary nameserver set as w.x.y.z it will always fail. If we hashed out the domain line, it would work, as now resolver would search for both domain suffix strings against the host being used in the lookup.

I’ll check the resolv.conf tomorrow when I am back in the office, but I am pretty certain this is how it was, however if its not then back to the drawing board (as it might then end up being a missing host record between the two domains/nameservers).

Just so we are clear, technically the host shouldn’t be using the nameserver a.b.c.d, nor domain suffix blah2.blah.com (as this is ONLY to be used from the management node) and not for the entire environment, will soon be making sure no one else depends on it and stopping it from answering requests in the future.

2 Comments

  • Luke April 9, 2009

    You can just put em on one line:
    search blah.blah.com blah2.blah.com

    L.

  • michaelf April 10, 2009

    Luke, yeah that is how setup my hosts. Did some checks yesterday and it’s not the sole issue. Vendor for app will investigate next week.

Comments are closed.