Question on Loadbalanced High-Availability MYSQL/Apache Cluster

[Pichi_B]

Hello,

I just finished setting up the How To's for Falkos High Availability Apache Cluster and High Availibility MYSQL Cluster. I did this on Debian Etch servers. So I could see that the differneces in the setups were the contents of the ldirectord.cf file. This is the file that controls the virtual server.

My question is:

Is there a way to combine the two virtaul servers (apache and mysql). I mean each How To tells us how to cluster one service i.e MYSQL or Apache. What I would like to do is cluster MYSQL and Apache on the same servers. Does the ldirectord.cf allow for more than one service to be virtualized?

I would go ahead and try this but I dont want to blow up what took me a few days to set up. I am a complete noob to LINUX and so I am doing all this slowly and trying to learn as much as possible.

Thank you for your help and especially to Falko for his great documentation,

Pete
Granada Spain

[Pichi_B]

OK after a while I got brave and changed the ldirectord.cf file myself. I included the two services (MYSQL & Apache) like so:

checktimeout=10
checkinterval=2
autoreload=no
logfile="local0"
quiescent=yes

virtual=192.168.0.105:80
        real=192.168.0.101:80 gate
        real=192.168.0.102:80 gate
        fallback=127.0.0.1:80 gate
        service=http
        request="ldirector.html"
        receive="Elvis has left the building!"
        scheduler=rr
        protocol=tcp
        checktype=negotiate


# Global Directives
checktimeout=10
checkinterval=2
autoreload=no
logfile="local0"
quiescent=yes

virtual = 192.168.0.105:3306
        service = mysql
        real = 192.168.0.101:3306 gate
        real = 192.168.0.102:3306 gate
        checktype = negotiate
        login = "ldirector"
        passwd = "ldirectorpassword"
        database = "ldirectordb"
        request = "SELECT * FROM connectioncheck"
        scheduler = wrr

I then rebooted the two load balancers and issued the following command:

bubba:/home/pete# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.0.105:80 rr
  -> 192.168.0.101:80             Route   1      0          0
  -> 192.168.0.102:80             Route   1      0          0
TCP  192.168.0.105:3306 wrr
  -> 192.168.0.101:3306           Route   1      0          0
  -> 192.168.0.102:3306           Route   1      0          0
bubba:/home/pete#

Seeing this was what I wanted. I was able to access both services via the virtual address 192.168.0.105. I added rsync for Apache using this How To:

http://www.howtoforge.com/mirroring_with_rsync

This gave me all the functionality I was looking for:

1. Replicated MYSQL databases
2. Mirrored Apapche Servers
3. Loadbalancing of services
4. Fault-tolerence of services

My next question would be how can I take advantage of this technology for my mail server which really is the most important service I have.

Thanks again to anyone who can help,

Pete
Granada Spain

[falko]

Originally Posted by Pichi_B

My next question would be how can I take advantage of this technology for my mail server which really is the most important service I have.

I think the best would be to create backup MX: http://www.howtoforge.com/postfix_backup_mx

[Pichi_B]

Hello Again,

Having finished the How To's High Availability Apache Cluster , High Availibility MYSQL Cluster, and Mirroring with Rsync I am wondering if I can go ahead and put this into a production enviroment?

The reason I am unsure is the version for MYSQL-MAX (now called MAXDB)in the How To is 5.0 and the currrent version is 7.5. I am unaware of how older versions of software are updated in the LINUX world. Are older versions safe to use?

So simply put would you feel comfortable running mysql-max 5.0 on a publically available server?

Another reason we are reluctant to use 7.5 is that it requires X and that could lead to security issues.

Thanks again,

P.

[falko]

MaxDB != MySQL. Take a look here: http://en.wikipedia.org/wiki/MaxDB

The latest stable MySQL version is 5.0.45, AFAIK.

[chris.zeman]

I have two questions regarding this tutorial.


1. Can I configure the cluster using a clean lamp install, or do I need to follow everything step-by-step?
2. Can I omit the second load-balancer?

Thank you,
Chris

[falko]

Originally Posted by chris.zeman

1. Can I configure the cluster using a clean lamp install, or do I need to follow everything step-by-step?

I recommend to do it step-by-step, but you can also start with a clean LAMP system.

Originally Posted by chris.zeman

2. Can I omit the second load-balancer?

Yes, but then you lose high-availability because the load balancer that is left becomes a single point of failure.

[chris.zeman]

Thank you, Falko. I might just have to see what I can do about getting just one more server. I'll probably wipe the clean LAMP install of Ubuntu I have on the two MySQL nodes and do it step-by-step like you said.

Thanks!
Chris

[chris.zeman]

I am to the point of install UltraMonkey, but I am having the following problem:

cybernetics@LoadBalancer1:/var/lib/mysql-cluster$ sudo apt-get install ultramonkey libdbi-perl libdbd-mysql-perl libmysqlclient14-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package libmysqlclient14-dev is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
  libalps-heap1-dev
E: Package libmysqlclient14-dev has no installation candidate
cybernetics@LoadBalancer1:/var/lib/mysql-cluster$

Should I install libalps-heap1-dev instead, or use libmysqlclient15-dev?

Thank you,
Chris

[chris.zeman]

I went ahead and installed libmysqlclient15-dev.

Now, I tried to bring up lo:0, but here's what happened:

cybernetics@Automation:/var/lib/mysql-cluster$ sudo ifup lo:0
SIOCSIFFLAGS: Cannot assign requested address

lo:0 is up, so can I just ignore the error message?

Thank you,
Chris