AFS Legacy Web Problems

Below is mainly a repost of something I sent to the US and Services Units. The headlines to note are, when moving someone from NFS to AFS find out if they use a legacy www.dai|dcs|cogsci.ed.ac.uk/~username/ type URL and check the following (or do it anyway):

   rfe amdmap/legacy_cogsci.home
   rfe amdmap/legacy_dai.home

You can replace ptn123 type entries with /afs/inf... paths is in the amdmap/groups file. See the email below for more details about running om openldap kick and umounting old amd mounts.

For legacy cogsci ~username URLs the file /group/project/websch/home.map

For legacy dai ~username URLs the symlink in the directory /public/southbridge/dai/docs/homes/

There should be no issue with legacy dcs ~username URLs.

That's it, remember to also check the AFS ACLs on the web dirs to make sure apache can access the files, may need to use "system:anyuser" for legacy web servers.

Original email

Henry had web problems following the move of his home dir to AFS. His URL is:

http://www.ltg.ed.ac.uk/~ht/

which is (in this case) equivalent to

http://www.cogsci.ed.ac.uk/~ht/

I know we say people should be using homepages, but at the same time there's no particular reason while this should stop working. He'd set the ACLs fine, but we were still getting "permission denied" error message.

The problem turned out to be that www.cogisci/~username URLs are mapped into the filesystem via the file /group/project/websch/home.map, which has this entry for "ht":

ht /legacy/cogsci/home/ht/public_html

The /legacy/cogsci/home map is controlled via:

rfe amdmap/legacy_cogsci.home

which had the entry

ht ptn051 ht

Hence apache was trying to access his old homedir on ptn051. To fix the problem the above was changed to:

ht /afs/inf.ed.ac.uk/user/h/ht

and then "om openldap kick" run on sleekit (www.cogsci) and then 'amq -u /amd/legacy/cogsci/home/ht' and 'amq -f'. Then /legacy/cogsci/ht pointed at his AFS home dir, and the web pages started working again.

We could have also fixed this by updating the /group/project/websch/home.map file, which would have fixed the web problem right away.

www.dai/~neilb type URLs have a similar potential problem. They rewrite to www.dai/homes/neilb/ and www.dai/homes is the directory /public/southbridge/dai/docs/homes/ and contains symlinks for each user, eg neilb -> /home/neilb/dai-home/public_html/, but there are also things like: ht -> /amd/legacy/dai/home/ht/public_html

So if someone moving to AFS has a www.dai ~url then the symlink in that directory needs updated and/or 'rfe amdmap/legacy_dai.home' (in this case ht doesn't have an active entry at all, so not worth fixing).

For DCS a change of dir to AFS won't affect www.dcs/~neilb type URLs, as they just map into /legacy/dcs/public//web/, no current or legacy homedir involvement.

So the point of this email, is just to say that there are a couple of places you may want to check if someones legacy web pages stop working after moving to AFS. Though if it does, people should be reminded that moving to homepages.inf might be a good idea.

-- NeilBrown - 01 Jul 2009

Topic revision: r1 - 01 Jul 2009 - 16:40:26 - NeilBrown
 
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