The new server is up and has all the software installed on it, so now we need to come up with a plan for moving the systems to the new setup.
It will /almost/ be possible to do it cleanly with DNS without anyone noticing--just bring apache up on the new server, whose scripts will read and write the database on the old server, and switch "www" to point to it. During the time when user's DNS caches are still live, some will point to the old server, but it will be sharing the same database, so both systems can run concurrently with no problem.
The glitch: images. Those are written to the filesystem rather than to the database, so images uploaded on one server will appear in the database of both, but only on one filesystem.
One way to fix this is to NFS-mount the image filesystem on both machines, but NFS is not terribly reliable and will increase network traffic.
Another way to do it is a more traditional switchover that will turn off the scripts on the old server when we enable to new one, and put up a static page that points people to the new server under a name other than "www" while their caches are still live.
Another thing to consider is moving "test" over first, pointing to the old database, and try the transition method on that before we try it on "www".
Jason, regardless of which way we go, you can start by reducing the lifetime of "test" and "www" in DNS, and make entries for "pliny" and "larousse". We also need to change the canonical name of ww to pliny--I can do that, but I'm not sure what else that might effect, so I haven't done it yet.
Lee Daniel Crocker wrote:
The glitch: images. Those are written to the filesystem rather than to the database, so images uploaded on one server will appear in the database of both, but only on one filesystem.
Isn't this true: for all images already uploaded, there is no problem. Only when a new image is uploaded, it will go to one or the other filesystem?
I think this could be tolerable if we disable image uploading on the "old" server (now the "database server"), just to make sure nothing gets uploaded there.
If a few images look broken for 24 hours while DNS propagates, it's no biggie.
Another way to do it is a more traditional switchover that will turn off the scripts on the old server when we enable to new one, and put up a static page that points people to the new server under a name other than "www" while their caches are still live.
That's good, too.
--Jimbo
(Jimmy Wales jwales@bomis.com): Lee Daniel Crocker wrote:
The glitch: images. Those are written to the filesystem rather than to the database, so images uploaded on one server will appear in the database of both, but only on one filesystem.
Isn't this true: for all images already uploaded, there is no problem. Only when a new image is uploaded, it will go to one or the other filesystem? I think this could be tolerable if we disable image uploading on the "old" server (now the "database server"), just to make sure nothing gets uploaded there.
Yes, that's the case; disabling uploads in the old server would still allow uploads on the new one, and pages would look fine on the new server, and there would be a few broken images on the old server during transition. It would also be necessary to disable rendering new equations on the old server as well, and that might be more annoying that disabling uploads.
I think that the database server should have it's IP changed to 130.94.122.199 (That's what the new server is currently using). We can then change the new server to use the current wiki IP.
This way, the upgrade is complete and immediate, and we don't have DNS issues, which we know can be more pain than they're worth.
Of course, there is the one scary question: "What if they don't come up with the right IP's and we can't do anything about it?". That would be bad, but I don't think it would be a problem if we just changed the IP's in /etc/sysconfig/network-scripts/ifcfg-eth0, and did a reboot when we were ready.
Either way, I'll try to set the TTL to a low value.
Jason
Of, course, we can do whatever. I just think that this will be the least painful for everyone involved.
Lee Daniel Crocker wrote:
The new server is up and has all the software installed on it, so now we need to come up with a plan for moving the systems to the new setup.
It will /almost/ be possible to do it cleanly with DNS without anyone noticing--just bring apache up on the new server, whose scripts will read and write the database on the old server, and switch "www" to point to it. During the time when user's DNS caches are still live, some will point to the old server, but it will be sharing the same database, so both systems can run concurrently with no problem.
The glitch: images. Those are written to the filesystem rather than to the database, so images uploaded on one server will appear in the database of both, but only on one filesystem.
One way to fix this is to NFS-mount the image filesystem on both machines, but NFS is not terribly reliable and will increase network traffic.
Another way to do it is a more traditional switchover that will turn off the scripts on the old server when we enable to new one, and put up a static page that points people to the new server under a name other than "www" while their caches are still live.
Another thing to consider is moving "test" over first, pointing to the old database, and try the transition method on that before we try it on "www".
Jason, regardless of which way we go, you can start by reducing the lifetime of "test" and "www" in DNS, and make entries for "pliny" and "larousse". We also need to change the canonical name of ww to pliny--I can do that, but I'm not sure what else that might effect, so I haven't done it yet.
-- Lee Daniel Crocker lee@piclab.com http://www.piclab.com/lee/ "All inventions or works of authorship original to me, herein and past, are placed irrevocably in the public domain, and may be used or modified for any purpose, without permission, attribution, or notification."--LDC _______________________________________________ Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
Jason's suggestions (of an ip number swap) sounds totally straightforward and appropriate to me. It means we don't have to fiddle with the vagaries of DNS, it's instant, and it's easily reversible.
--Jimbo
(Jimmy Wales jwales@bomis.com): Jason's suggestions (of an ip number swap) sounds totally straightforward and appropriate to me. It means we don't have to fiddle with the vagaries of DNS, it's instant, and it's easily reversible.
OK, I'll just need to take a few minutes to wrap my brain around how that will work with the software (...drawing diagrams...)
I am only in control of wikipedia.com, I don't know who can change the TTL on wikipedi.org subdomains.
Jason
Lee Daniel Crocker wrote:
Jason, regardless of which way we go, you can start by reducing the lifetime of "test" and "www" in DNS, and make entries for "pliny" and "larousse". We also need to change the canonical name of ww to pliny--I can do that, but I'm not sure what else that might effect, so I haven't done it yet.
-- Lee Daniel Crocker lee@piclab.com http://www.piclab.com/lee/ "All inventions or works of authorship original to me, herein and past, are placed irrevocably in the public domain, and may be used or modified for any purpose, without permission, attribution, or notification."--LDC _______________________________________________ Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
Oops... I was wrong here... I guess I've only messed around with the .com names in the past. Don't mind me... Something is wrong with my brain today.
Jason
Jason Richey wrote:
I am only in control of wikipedia.com, I don't know who can change the TTL on wikipedi.org subdomains.
Jason
Lee Daniel Crocker wrote:
Jason, regardless of which way we go, you can start by reducing the lifetime of "test" and "www" in DNS, and make entries for "pliny" and "larousse". We also need to change the canonical name of ww to pliny--I can do that, but I'm not sure what else that might effect, so I haven't done it yet.
-- Lee Daniel Crocker lee@piclab.com http://www.piclab.com/lee/ "All inventions or works of authorship original to me, herein and past, are placed irrevocably in the public domain, and may be used or modified for any purpose, without permission, attribution, or notification."--LDC _______________________________________________ Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
-- "Jason C. Richey" jasonr@bomis.com
Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
How's that? I'm sorry, I don't understand. It's all in my register.com account, right?
Jason Richey wrote:
I am only in control of wikipedia.com, I don't know who can change the TTL on wikipedi.org subdomains.
Jason
Lee Daniel Crocker wrote:
Jason, regardless of which way we go, you can start by reducing the lifetime of "test" and "www" in DNS, and make entries for "pliny" and "larousse". We also need to change the canonical name of ww to pliny--I can do that, but I'm not sure what else that might effect, so I haven't done it yet.
-- Lee Daniel Crocker lee@piclab.com http://www.piclab.com/lee/ "All inventions or works of authorship original to me, herein and past, are placed irrevocably in the public domain, and may be used or modified for any purpose, without permission, attribution, or notification."--LDC _______________________________________________ Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
-- "Jason C. Richey" jasonr@bomis.com
Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
Yeah, I noticed that right after I sent this mail... For some reason, I thought that wikipedia.org was a different situation (in terms of DNS) than wikipedia.com. I don't know what made me think that.
Jason
Jimmy Wales wrote:
How's that? I'm sorry, I don't understand. It's all in my register.com account, right?
Jason Richey wrote:
I am only in control of wikipedia.com, I don't know who can change the TTL on wikipedi.org subdomains.
Jason
Lee Daniel Crocker wrote:
Jason, regardless of which way we go, you can start by reducing the lifetime of "test" and "www" in DNS, and make entries for "pliny" and "larousse". We also need to change the canonical name of ww to pliny--I can do that, but I'm not sure what else that might effect, so I haven't done it yet.
-- Lee Daniel Crocker lee@piclab.com http://www.piclab.com/lee/ "All inventions or works of authorship original to me, herein and past, are placed irrevocably in the public domain, and may be used or modified for any purpose, without permission, attribution, or notification."--LDC _______________________________________________ Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
-- "Jason C. Richey" jasonr@bomis.com
Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
I belive that it would be a worthwhile investment for wikipedia to invest in an easyDNS account. i believe its important for the project to have full control over their dns at all times.... and its not expensive at all. i use it and i absolutely love it.. and if a couple of people want to, im willing to chip in for it.
Lightning
----- Original Message ----- From: "Jason Richey" jasonr@bomis.com To: wikitech-l@wikipedia.org Sent: Tuesday, May 06, 2003 12:44 PM Subject: Re: [Wikitech-l] Transition to new server
Yeah, I noticed that right after I sent this mail... For some reason, I thought that wikipedia.org was a different situation (in terms of DNS) than wikipedia.com. I don't know what made me think that.
Jason
Jimmy Wales wrote:
How's that? I'm sorry, I don't understand. It's all in my register.com account, right?
Jason Richey wrote:
I am only in control of wikipedia.com, I don't know who can change the TTL on wikipedi.org subdomains.
Jason
Lee Daniel Crocker wrote:
Jason, regardless of which way we go, you can start by reducing the lifetime of "test" and "www" in DNS, and make entries for "pliny" and "larousse". We also need to change the canonical name of ww to pliny--I can do that, but I'm not sure what else that might effect, so I haven't done it yet.
-- Lee Daniel Crocker lee@piclab.com http://www.piclab.com/lee/ "All inventions or works of authorship original to me, herein and
past,
are placed irrevocably in the public domain, and may be used or
modified
for any purpose, without permission, attribution, or
notification."--LDC
Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
-- "Jason C. Richey" jasonr@bomis.com
Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
-- "Jason C. Richey" jasonr@bomis.com
Wikitech-l mailing list Wikitech-l@wikipedia.org http://www.wikipedia.org/mailman/listinfo/wikitech-l
On Thu, May 08, 2003 at 09:29:22PM -0400, Lightning wrote:
I belive that it would be a worthwhile investment for wikipedia to invest in an easyDNS account. i believe its important for the project to have full control over their dns at all times.... and its not expensive at all. i use it and i absolutely love it.. and if a couple of people want to, im willing to chip in for it.
Lightning
I use easyDNS right now, and I have to agree - it is awesome. The web interface is good, customer service is quick, and my transfer from register.com (who messed up my WHOIS record _twice_ leaving me stranded for a week [their automated scripts made an error, boo!]) was pretty painless.
Lightning wrote:
I belive that it would be a worthwhile investment for wikipedia to invest in an easyDNS account. i believe its important for the project to have full control over their dns at all times.... and its not expensive at all. i use it and i absolutely love it.. and if a couple of people want to, im willing to chip in for it.
Well, we do run our own DNS servers, too. It's really just a matter of convenience and tradition that we've never moved the DNS from register.com to our own DNS servers. We could do that, it's just a matter of time.
--Jimbo
wikitech-l@lists.wikimedia.org