Apache supports load-balancing, you can put several in parallel without any problem J And it does a very nice job in load-balancing/failover for the backends through mod_proxy_balancer (though a health-check option at HTTP level would be welcome) The problem is more with the applications you put behind it. If you have several apache that forward to several application servers (be it PHP, Tomcat, Weblogic, Websphere, etc…) you need to make sure that: - one “client” always end on the same front-end apache server + that the queries are always forwarded to the same app server (using session id) - or that the app server are working in a cluster to synchronize their sessions If you can afford a hardware load-balancer, do so. But even there, you’ll have to setup several such boxes in parallel one day or another, with vrrp or hsrp or a similar protocol. You can also take a look at the SRV record for DNS (http://en.wikipedia.org/wiki/SRV_record) and pray for the browser to support it. From: Harsimranjit singh Kler [mailto:simran4u2@xxxxxxxxx] Thanks for details. One last question Why Apache not Support failover support which is basic for any load balancer setup ? Any plan of HA in future releases of httpd? On Mon, Feb 6, 2012 at 4:08 PM, DENIS Laurent <Laurent.DENIS@xxxxxxxxxxxxxxxx> wrote: Basically, you have one IP address that is used by two hosts, active one only one at a time. If one service fails, the other node take the IP thanks to keepalived. This works only if you’re on the same network segment. Google on “vrrp keepalived apache” and you’ll get this first link: http://www.cyberciti.biz/faq/rhel-centos-fedora-keepalived-lvs-cluster-configuration/ From: Harsimranjit singh Kler [mailto:simran4u2@xxxxxxxxx]
Intially i want failover setup only with two node can you explain little about vrrp + keepalived. else some reference link how i can achive it step by step(on linux setup only) ? On Mon, Feb 6, 2012 at 3:12 PM, DENIS Laurent <Laurent.DENIS@xxxxxxxxxxxxxxxx> wrote: If you just want failover on the head apache: use two nodes with vrrp + keepalived (if you’re on linux) to monitor your service. If you need load-balancing, then you should use two VRRP addresses with DNS round-robin. But you’ll stumble on client-server persistence problem if you don’t use tomcat clustering. From: Jaco Kroon [mailto:jaco@xxxxxxxxx] Not that I'm aware of but someone else on the list may very well know something I don't.
On Mon, Feb 6, 2012 at 2:43 PM, Jaco Kroon <jaco@xxxxxxxxx> wrote: Hi,
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