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Possible Bug: DNS Cluster Sychronization Problems

Discussion in 'Bind / DNS / Nameserver Issues' started by cPanelKenneth, Mar 11, 2009.

  1. cPanelKenneth

    cPanelKenneth cPanel Development
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    This is already fixed in EDGE ( or maybe internal builds only still ). When configuring the DNS Sync members and a hostname is provided, we perform an IP lookup and use that in lieu of the hostname.

    Another behavior we changed in this regard is in the past is dnsadmin would prefer the hostname over IP addresses. We now consistently use IP addresses throughout the synchronization system.

    EDIT:
    clock syncing is annoying :P
     
    #1 cPanelKenneth, Mar 11, 2009
    Last edited: Mar 11, 2009
  2. LiNUxG0d

    LiNUxG0d Well-Known Member

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    Hey all,

    Just an FYI for all of you.

    Let's say you have a server called: host.example.com

    This server gets rooted and you need to migrate all the accounts from its poor self to another new box with a fresh kernel.

    You set up a new server called: host.example.com

    You set the same host name on the new box as the same host name as the other box, to keep everything mirrored properly.

    You create a cluster on both boxes and set the new one to synchronize with the other before you transfer.

    Transfers will work, but NS Synchronization will not.

    We tried changing the host name on the old - rooted - box and the next transfer worked flawlessly!

    I'm thinking that using hostnames is the culprit, when synchronizing, instead of IPs. cPanel should consider taking a look at this to fix it in a next release. I would send in a support ticket, but this way is quicker.

    Hopefully a mod will pick it up! :D

    Thanks all!

    My 0.02$ as usual! ;)
     
  3. LiNUxG0d

    LiNUxG0d Well-Known Member

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    Cool!

    Hopefully these changes will be ported to RELEASE some time in the near future. ;) It's not a big deal now that I know, but I can just see an admin going:

    "I'll just transfer these 400 accounts..."
    *6 hours later*
    "WHAT? I have to re-transfer because the DNS isn't propagated and the sites have stale data? Crap on a stick!"

    :D
     
  4. cPanelKenneth

    cPanelKenneth cPanel Development
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    Hmmm, for that scenario I think the Express Transfer option in the Account Transfer interface would help.

    I'm not certain the dnsadmin changes will make the 11.24 series as there are a number of large changes, beyond what I already mentioned. Some of the changes bring improved performance and reduced memory usage. These changes need to 'bake' a little more. Many of the changes are available in our EDGE branch for those who want to test early.
     
  5. LiNUxG0d

    LiNUxG0d Well-Known Member

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    Without sounding like a pest, which I'm sure I do... it's an EDGE release... so really I wouldn't want my customer traipsing along the EDGE, however, issues like this should be looked in to more seriously and make their way to RELEASE sooner than later, because RELEASE is supposed to be for conservative types. But if people on EDGE have less bugs, what's the point of using RELEASE?

    We've been issuing migrations lately, as well, that have been succeeding, but when we go and "du -cksh" the /home/username, we notice that files are missing... but cPanel said the transfer completed successfully. These kind of issues are really weird. And we've seen it on a few networks, so it's not so much a problem with ONE of my servers, since really, the only thing all these have in common - since hardware and networks aren't part of the equation - is cPanel/WHM.

    It's just weird. These issues started a while back, like, 2 months ago maybe? We never brought it up because we thought it was a problem with a server we migrated to/from, but now it just happened between two networks that have no relation to the first we used.

    I know that these issues would require more investigation, but when WHM goes, "Copy completed successfully!" and the size on disk of a homedir doesn't match up, it makes me cringe. ;) Since we're talking about copying, etc, I thought I'd bring it up... which I know I shouldn't. ;)

    Thanks Ken,
     
  6. cPanelKenneth

    cPanelKenneth cPanel Development
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    EDGE users do not have less bugs ;) Consider EDGE a public alpha ( or sometimes even a public alpha ) with all the fun that entails.

    As for dnsadmin, I think the change we discussed in this thread is now available in RELEASE and CURRENT.

    Are there any patterns to the files that are skipped? For example, are they large files? Are the files owned by user 'nobody' or by the account?

    When creating the cpmove file, we attempt to perform as many actions as possible as the user, thus files/directories the user cannot access will be skipped. Are there any indications of the problems in the transfer logs ( these are found in /var/cpanel/logs ) ?
     
  7. LiNUxG0d

    LiNUxG0d Well-Known Member

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    Hey Ken,

    We have a perfect example. We cannot see anything funky on the owership/perms side of things.

    Here's the funk:

    - We used the 'Copy multiple Accounts..." option in WHM.
    - The user complained - after transfer - that files were missing from one of his domains.
    - We made a manual /scripts/pkgacct of his domain.
    - We SCP'd it.
    - We backed up the users public_html/ (incomplete one) and untarred the cpmove and homedir.tar from the backup and copied it over, retaining perms/ownerships.
    - The user reports all is normal.

    We've also done the following:

    - Grabbed that tar: cpmove-user.tar
    - Use the 'Restore a Full Backup/cpmove file' option.
    - The files are missing upon restore.
    - We untar manually and untar the homedir.tar and the files ARE THERE.

    The restore didn't restore them, but the files are in the homedir.tar and owned by user:user and not nobody; they are 755 or 644... straight perms.

    I have a tar (original cpmove) that I can SCP to you guys if you guys are interested in testing what I'm working with because frankly... I noticed flakyness in the restore/transfer account options in the last couple months, and this is getting scary since we're prepping to migrate LOTS of customers... "seamlessly". :P

    Thanks for your time Ken. If you want a copy of the cpmove-user.tar that we have, to test a restore (we've done it on 2 servers now, unsuccessfully) we'd be more than happy to oblige in sending it over.

    We'd need this looked at ASAP.

    Thanks so much,
     
  8. cPanelKenneth

    cPanelKenneth cPanel Development
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    Would you mind opening a support ticket on this at https://tickets.cpanel.net/submit/?reqtype=tickets

    Mark the ticket "ATTN: QA restoring accounts"

    Especially if we could have access to:

    1. The cpmove file
    2. The backup you made of the users public_html ( for comparison ) before resolving the issue.
    3. Access to the server where this occurred ( only for investigation. If we need to make any changes we'll coordinate such with you before doing them ).

    The above should give us the information needed to track this down.

    Thank you very much by the way.
     
  9. LiNUxG0d

    LiNUxG0d Well-Known Member

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    Hey Ken,

    Done. I've submitted the request (395282). Feel free to restore it to that box, or take the tar and run. I don't mind.

    /home/cpmove-netrich.tar.gz

    The account doesn't exist on the server right now, go ahead and restore, and compare all you like. No worries.

    Thanks and let me know. :)
     
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