High Availability Server

[padani]

Hello all ,

Any body have information about setting up a plesk server may be two.So that in the event of one server going down other can took the place automatically .
Can this be done with plesk ?? .Please help with your knowledge and information on this issue.

 

[wsani]

It would be difficult because you would have to replicate the plesk databases (psa) on both servers. That would be the first challenge. You would also have to setup a SAN to serve the web and database files, which is yet another challenge. I suppose a something like double-take could help you along the way but I don't know enough about the software to say it is done.

Basically, it would be a hack to get it load-balanced.

 

[padani]

Great reply my frined thank you for the thoughts. I had done some googling .I found some answers .I will update you on that soon

 

[yurtesen]

You probably will need a load balancer as well...

You might want to check another web hosting automation product from Parallels which can do this natively.
http://www.psoft.net/HSdocumentation/sysadmin/understanding_load_balancing.html

 

[padani]

Hey ..yurtesen

You are pushing Hspere .But i am certainly behind the mighty plesk ..The post is intended to look for ideas in high availability PLESK server.Not another panel
Anyway thanks for the info.

 

[atomicturtle]

Its a little tricky, but yep totally possible. With two servers you could do a hot standby, and sync them together with rsync. There are a lot of ways to do it, personally I use a 3 layer design. Load balancer layer, front end server layer, and file server layer. The key directories to sync are /var/qmail, /var/www, /var/lib/mysql, and /usr/local/psa/var/certificates/

 

[padani]

Great info ...Atomic

Great info ...Atomic
I was a die hard user of your Repo

 

[yurtesen]

Hey ..yurtesen
You are pushing Hspere .But i am certainly behind the mighty plesk ..The post is intended to look for ideas in high availability PLESK server.Not another panel
Anyway thanks for the info.

Well H-Sphere is more featured and better priced. I just wanted to point out that, since Parallels bought H-Sphere, you can now have a better product from Parallels which does what you are asking for and more so that you know that you have other options A real solution is still better than a hack over existing software. But as you wish

 

[padani]

Any way thanks .May be your info will come in handy some other time

 

[thewolf]

Its a little tricky, but yep totally possible. With two servers you could do a hot standby, and sync them together with rsync. There are a lot of ways to do it, personally I use a 3 layer design. Load balancer layer, front end server layer, and file server layer. The key directories to sync are /var/qmail, /var/www, /var/lib/mysql, and /usr/local/psa/var/certificates/

Could you elaborate a bit on your sync setup? E.g. how do you automate the replication of the MySQL dbs?

Also, would you setup work over a WAN?
E.g. main Plesk installation in a datacenter and hot standby Plesk installation in a separate datacenter (this will allso require DNS updates to point the sites to the new IP addresses).

Thanks.

 

[atomicturtle]

So for the load balancing layer, we use squid (for web, if you need mail, MX records, etc.) Squid by itself in a reverse proxy configuration also gives you a considerable performance boost. You can have as many of these out there as you need, using round robin dns. (Consider this the geo-load balancing layer) This would let you scale up capacity just by adding more squid nodes.

The fault tolerance layer you can put together a lot of different ways, with the squid layer above this using virtualization becomes both a high availability and high performance option. What you would do here is establish a basic virtualization cluster using a combination of a SAN and 1+n phyisical virtualization nodes. Virtualization technology itself is up to you, they all work great (virtuozzo, vmware, xen, kvm, etc). In this configuration you have a single active plesk node, the hot spares just copies living on the SAN (obviously, a single point of failure).

This is probably the most basic high performance/high availablity configuration you can build on a low budget.

If you needed to get into mysql clustering, thats a much longer conversation. The lowest level is just a basic master/slave replication environment. Mysql itself has more advanced commercial clustering options, and there are open source projects like memcached.

 

[thewolf]

Since we're looking to replicate Plesk over a wide area network (e.g. to a datacenter in a different geographical location), we cannot leverage our SAN and VMware Infrastructure for that.

Any other ideas to automate Plesk replication to another datacenter?

Thanks.

 

[atomicturtle]

In that case I'd do a load balancing layer to handle the failover then:

1) Plesk backup and restore between boxes, and regular rsyncs to keep the hot spare as close to whatever is active.

2) Run some virtualization between nodes, and then use that to keep the guests up to date

3) run SAN to SAN replication between sites

 

[thewolf]

Thanks for the reply, but it looks like any of the suggested solutions would required quite some manual work (e.g. scripts to reconfigure the Plesk sites at the other datacenter to use different IP addresses) and would not provide near real time replication (e.g. replication for MySQL databases, replication for changes inside Plesk, like protected directories, new databases, etc.).

What I'm looking for is a semi-automated solution for the above.

Perhaps Plesk is not the right tool for this job?

Any other suggestions?

Thanks.

 

[atomicturtle]

They all require extra engineering on your side, you also might want to check out Plesk Expand