Domains vs. Logicalhosts
With 5.1.1 come domains as a replacement for logicalhosts (5.0.5). Here was my initial confusion, the documentation states that a domain is an instance of a logicalhost, but is it really? A domain is made up of an integration server and a JMS manager. Is this equivalent to a logicalhost? In my opinion, not really. I see disadvantages to domains, especially in situations where a process spans multiple IS's and IQ managers. As most of our processes do not span as such, I feel that we can get around this. Another disadvantage is deploying from the Enterprise Designer because the system structure is not representative of the physical structure of the application servers and JMS managers. On the flip side, I see an advantage with deployments through the Enterprise Manager via build files. This allows for multiple deployments to multiple domains at the same time with being selective of what is enabled and what is not. This will help out with failover.
So I guess in my above rambling I am just offering my opinions on domains vs. logicalhosts and would like to hear other's views on the same topic. It took me a while to get a good grasp on what the real difference was because I was getting conflicting information for the documentation and support. When I was finally able to see what a domain really is, it definitely made it easier to visualize what the 5.1.1 system layout will be when we do upgrade in the upcoming months.
Bryan
[1463 byte] By [
bgrant88] at [2007-11-26 9:51:36]
# 1
Hi Bryan,
you can think of Domains as an instance of a Logical Host in JCAPS. A Domain has one Application Server and one JMS IQ Manager. If you need multiple Domains (say you are doing Load Balancing of some sort) then you just create multiple domains inside your Logical Host.
Why do you see a disadvantage in the Domain concept if your process spans multiple IS's?
Deploying from eDesigner is meant for development/testing only. If a prodction envrionment you would use the Enterprise Manager or the deploy command line tool.
The domain concept comes straight from the Sun App Server, so it will not be foreign to many people.
Sebastian.
# 2
The way to think about a logicalhost in 5.1 is that it is just the installation directory of the application server and jms server. The logicalhost as such does not represent a process, e.g. it cannot be started / run. A domain is an application server plus JMS server that can be started / run. That is how the term of "instance of logical host" came about, following the analogy of a Java class (compare a logicalhost) and a Java object (a domain).
The concept of logicalhost in the Environment in Enterprise Designer is now merely a logical grouping of an application server and a JMS server: it makes no difference how many application servers / JMS servers are grouped under a logical host. This is a big difference with CAPS 5.0.
One of the advantages of this change from 5.0 to 5.1 is that it much closer resembles the way that other application servers work, e.g. the Sun Java System Application Server 8.x. So eventhough it takes some time for 5.0 users to grasp the new terminology, for those users that are new to CAPS the new concept / terminology is much easier to understand.
# 3
As most of my experience with application servers stems from the use of logicalhosts in 5.0.5 for the past couple of years, I can see how I am a bit stuck on the old terminology. I am sure this new structure has many advantages that I cannot recognize yet but I am sure it will come to fruition soon enough.
# 4
And, while in ICAN your instance of a logicalhost could have multiple Integration Servers and multiple JMS IQ Managers, in JCAPS your domain (instance of a LH) can have but one IS and one IQ. So as you migrate from ICAN to JCAPS you will likely have more domains than you had LHs.
Also, there are implications in management of your domains under the control of a single Enterprise Manager as anyone with the rights to deploy/undeploy in the EM has those rights on all domains under its control.
# 5
I think the best way to understand the concept of a domain is to take a look at the Sun Java System Application Server 8's documentation. The CAPS 5.1 Integration Server is completely based on the SJSAS 8 Platform Edition with certain modifications.
The benefit of dealing with domains is that it allows better deployment management. One of the previous posts made a good point that the logical host in CAPS 5.1 is more or less like an installation of a bunch of files, and it won't be able to do anything until a domain is created. In this regards, a domain in CAPS 5.1 is almost the same an Integration Server back in 5.0.5 and prior.
On a second note, we should be very careful about associating failover/loadbalancing with the Integration Server. As far as I know, the SJSAS 8 PE and thus the IS in CAPS in 5.1 do not support these capabilities. Because of this, I have asked myself the question about what is the value of creating multiple domains in one Logical Host. If LB and HA are required qualities in a deployment, I would immediately conside using the SJSAS EE as the Runtime for my CAPS applications.
In terms of deploying an application, coming from a SJSAS background, I have found the isadmin command in $CAPSHOME/logicalhost/is/bin easier to tackle than the deploycli CLI utility. This command is almost identical to the asadmin command in the Appserver which has a very good documentation in the SJSAS reference manual. It does so much more than just deploying an application. In fact, for most of the Integration Server administration tasks, I prefer this over the EM or the IS Administration Tool.
Xuekun
# 6
The concept / architectural change in 5.1.x is very good when compare to 5.0.x.
Basically all 5.1.x major components are independent like LH, EM, Rep.
Where as in 5.0.x, all these are dependent on repository. So using 5.1.x, we can reduce the time and complexity(easy of use) in the real time work / environment.
I guess currently, it supports load balancing & HA on IS, not on IQ Manager. I mean it supports only on Integration Server (IS) but not for JMS servers (IQ Manager.).
For supporting all these i.e. HA, & Load Balancing, SUN had released recently JMSGrid as an add-on of JCAPS 5.1.x
# 7
Hi,
I stumbled on to these posts and wanted to get some advice from you guys. Here is where we stand.
We currently have Seebeyond 5.0 SRE ( Not ICAN) in production and our plan is to migrate to JCAPS. We already have JCAPS 5.1.2 in our Dev and are working on migrating the components. With this background here are my questions.
1. We have about 100 plus eways with various memory requirements, since they all run(now) in their own JVM, our configuration had been easy to confine to each eway. But in JCAPS, we will have to run multiple number of these eways in a single domain, how has this been in your experience as this is same in ICAN as well? How was the architectural decision made when you migrated from 453/SRE to ICAN if you did.
2. Have you guys used Seebeyond IS and seebeyond JMS or SUN App server? If yes, did you see any better performance.
3. I am experimenting on JMS grid but that only gives me HA for JMS still nothing for IS. What did you do for getting the HA for your Integration servers?
3. What, if any, major production issues did you guys see.
Any help in this matter is greately appreciated.
Thanks
Kinnu
# 8
I am surprised there is nobody out there that could answer my question. Is it because it is new technology that nobody tried yet in production? Any help will be greatly appreciated.-Thanks
# 9
1. We have been trying to design a methodology around load balancing on a domain/IS but it is still in the works. My one recommendation is to configure all domains/IS with a minimuam of 1GB heap.
2. We have only ever used Seebeyond IS
3. With JMS grid, you have the ability to distribute the load across multiple IS's. As for an HA approach for IS's, I guess it depends in the design and use of JCAPs to best answer. With a system-wide publish subscribe model, the ability to distribute subscribers across IS's does 75% of the work. You would then just need to account for the situation where your publication IS goes down. This could be done via HACMP or comparable product.
I do not have much experience in other system designs so I regret that I cannot offer more. Please email me separately if you would like to take a look at our proposed HA architecture.
4. Since we are still on 5.0.5, major issues that we have hit revolve around logins and security. We have never been able to build a user-friendly environment with each developer having their own login (we all use Administrator). When using individual logins, we have found that there are code discrepancies, naming differences and other oddities that revent successful deployments and operations. JCAP 5.1.2 is greatly improved and I look forward to the upgrade in the next month or two.
# 10
Thanks for the reply.
Could you please give me your email address that I can use to send a separate email. I have some specific questions to somebody who have already used this for a while. I have played around a bit and found some interesting bugs/issues that I have been working with Seebeyond about. But anything related to performance tuning or architectural inquiry, they would say I need to talk to professional services. We are working on getting somebody from Sun, but i wanted to do my own research.
Thanks
Kiran
