Failover

[Grep_ler]

Hello,

Does anyone know if CPanel works with GFS for active/active or active/passive failover?
If it does not is there any other failover software that it will work with?

Thanks

Dan

[theMikeroy]

I'm highly interested in such a fialover solution as well... it's been a pain to find anything that resembles a solution...

you'd think that a failover for cPanel would be something that was done before... Maybe it has, but i havn't found a thread in these forums that has indicated such... A couple of questions but no answers...

Hello?? Anyone? cPanel Staff maybe?? We want a failover solution that works with cPanel!
It's simple... 2 servers running at the same time, sharing everything including state. Both computers are responding to http requests at the same time, however the 'backup' computer won't send any output until the master is having a problem...

How could we do this??

[shaun]

There is alot more to failover than just using a shared FS and mounting it on both servers... with http, ftp, pop, imap it would probably work fine but with mysql thats a bit more complicated.

[freedog96150]

I think that asking cPanel to handle failover is asking a bit much of a hosting software. Look higher up the food chain at a hardware solution like router that can manage failover/load balancing/etc at the hardware layer.

Just my 2 cents

[zigzam]

I think that asking cPanel to handle failover is asking a bit much of a hosting software. Look higher up the food chain at a hardware solution like router that can manage failover/load balancing/etc at the hardware layer.

Just my 2 cents

Why? Hsphere does it.

[shaun]

Doesnt matter if you have the best failover hardware in the world, if the software does not support it, it's not going to work.

cPanel for the most part is pretty simple, and if you really put the effort into it i think you could get a redundant solution up and running but the 3rdparty software is another story. For example, it would take 3 servers to run mysql in a cluster... Also mailman seams like it might be a tricky one also.

[theMikeroy]

What about DRBD or rsync working with Heartbeat?

Understanding that cPanel does alot of it's own updates, couldn't you just tell rsync or drbd to mirror the whole hard disk instead of a specific directory / mount point?

What i was thinking:

Set up 2 servers with an OS (1 master, 1 slave)

Get drbd or rsync installed on both

Get Heartbeat installed and config'd

Install cPanel on master

start heartbeat and rsync

Do an initial sync

Everything else from that point should be just incremental updates. When cpanel does an update, rsync should automatically apply the filesystem changes to the 'slave' node

Heartbeat would take care of the failover, which i can't imagine being that big a deal in terms of implementation, unless there's something about cpanel which would inhibit this.


Am I making sense, or am i neglecting some fundamental issue which prevents this from working?

[chirpy]

You would have to have a separate MySQL setup though, because you cannot use rsync to mirror the databases. How are you going to deal with IP address changes? Both servers would have to be configured to listen for the same IP address assignments.

[myusername]

I would think heartbeat would handle the IP address assignments.

I think those that really need failover are going to be dedicated server owners, so even if it were the server main IP that was being swapped out it would be a start.

Even with hardware load balancers to handle the IP part, there is no good solution out of the box for a shared file system.

You can get a hardware load balancer, and configure mysql cluster with relative ease....though expensive.

However, a good easy way to attach a SAN or other huge storage array to cPanel is a mystery to me. If I could figure out how to attach about 5-10 TB of storage to a cP server and have an arbitrary number of apache web servers accessing this shared file system, I would be an extremely happy man.

A great start for cpanel cluster would be a sharable file system. they already have a way to "add cluster" for DNS services, why not storage next? Sounds like a logical evolution for cPanel.

[hostserve]

Good afternoon Folks,

Cpanel has a MASSIVE client base.. there are more than enough of us that are interested in doing it to make it worth while.

In fact, I'd be willing to pay 10% or 15% extra for the "clustered version" if Cpanel was to build it as an add-on or specific version. The end result of redundancy and failover is what is most important.

If Cpanel is not willing to do it, we need to find someone that has the ability to do it and collectively sign "letters of intent" to buy the "road-map" or "directions" on how to do it so that the people who develope it know there are real people out there willing to buy it.

I think the important thing to do is to stand back and say "in order to do this we have to do this and this and this and this" and layout the steps, see how it has to happen and build it, everyone that I have spoken with seems to want to say "it can't be done because of this" collectively its time to build a solution to the problem rather than looking at it from the list of "why it can't be done"...

Cpanel is a wonderful product, and has grown up in leaps and bounds as a tool and standard in the hosting world... to ignore the importance of failover and clusters would be limmiting the future growth and expansion as many of us have more than 1 cpanel server and are looking for real world commercial reliability.

From the standpoint of building a truely competitive and reliable hosting company this is the only thing Cpanel is missing... These are just my opinions...

[myusername]

I have to agree there. How about a cPanel lite? One without all the bells and whistles. One that just had Apache (orand maybe a secondary web server option like lite httpd) , DNS, MySQL etc. Cluster compatibility as an addon or part of the main product would be a great thing, and we would be looking at something more enterprise ready.

Nothing annoys programmers and admins more than all the fancy stuff that never gets used and consume resources, hets inthe way that comes in the base cPanel version.

All aside I'd gladly sign a "we want cluster" petition

[hostserve]

… an after thought, in fact from the discussions I have seen here there is not a lot that needs done out side of what has already been said or written:


Hardware requirements:

- Servers 12:
o DNS Servers (minimum 2) – DNS only cpanel
o Web Servers (minimum 3) – Full CPanel
o Mail Servers – inbound (minimum 2) – full cpanel
o MySQL Servers (minimum 3) – in MySQL cluster (no cpanel license)
o Storage Servers (minimum 2) – stand alone running rsync or something similiar
- Switches 2:
o Front end switch or load balancing device
o Back end switch (GB capable) to connect Storage servers or NAS to web servers

As for hardware, I think that is it…

The load balancing switch should be able to determine the response time from the server and decide that if the server does not respond fast enough it should stop sending packets to it.

All 3 web servers would need to be configured identically. /home and /var and /etc should most likely all be written to the shared storage so all the servers are using the same directories. Most of this can and should be done at the hardware level and not cpanel.

They would all use clustered DNS.

The mail servers should run linux heartbeat incase of failover, one assumes the others IP address and responds as if it was the primary in case it fails. Mailboxes should be stored on the storage servers. There should be no locking or file connection issues because only one server would be accessing the files and receiving e-mail. Once the server fails its connections to the files would drop and the new server would respond, acting as the primary server.

The web servers are fine to run all 3 at the same time… the only issue should be if the bandwidth calculations are done and how logs are handled. This could possibly be handled via some kind of peril script run by a back up server every night to merge all the servers raw access logs into one the client sees. The caveat with this is the clients stats would always be 24 to 48 hours behind.

MySQL would be fairly simple, I believe, as I’m told MySQL has a cluster setting and they would run and handle everything and act as one and cpanel apparently will let you connect to a separate MySQL server.

Cpanel should not care if we were to run a cluster in a format like this as you’d run full cpanel licenses on the web servers and mail servers. DNS only versions on the dns servers. And if you used the heartbeat feature from linux you would not be in a license violation situation as far as I can see as they would only be running one at a time… but even if you needed the extra license who cares…

I believe that this would allow for the servers to handle all fail over aspects and outage issues… it would also let the web servers grow to handle load.. you could dynamically add them as you needed them and based on load.

Off the top of my head I can’t think of anything else that would need to be.. but I’m sure others of you will see holes or have suggestions… to which I welcome your thoughts, comments and suggestions.

[myusername]

Rsync is not fast enough for heavy environments. There needs to be shared storage. Your apache/application servers should be able to connect to a centralized storage array.

Your storage array could be rysnced if needed to a standalone backup array, but a raid system would probably be sufficient for most.

Main thing there is an accessable filesystem all the app servers can talk to. That way you are not limited to a few traditional hard disk (maybe 500 GB x 6?) in one simple server.

If you can get the ability to connect to shared stoarge you can add fun things like a SAN (or whatever!) But I have not seen any way to get say 10 TB of storage accessable by multiple cPanel app servers.

[cytexone]

We are very interested in a failover / clustered solution for cpanel. If anyone can do this we are willing to contract them.

Thank you

Dan
CYTEXONE
dan@cytexone.com

[bargainhost]

There is a company who are using a Failover system for Cpanel: http://www.hostingzoom.com/

News Article: http://www.hostsearch.com/news/hosti..._news_5081.asp

I dont think they will pass on their secrets but this proves that it is doable.