I have a fair bit of understanding of the webserver namely apache httpd. We have a web component which is is build in Angular, HTML5, CSS3.
We deploy the UI compoenent in apache httpd 2.4.
Recently someone proposed to replace this with F5 load balancer.
Is it possible to replace webserver with load balancer ?
Can we deploy the html components in F5 load balancer ?
My understanding is that load balancer helps in clustering the webservers based on different algorithms like Round robin, Weighted round robin, Least Connection etc and cannot indpendently the server the requests coming from end user.
You can build out basic web functionality in iRules, but if you need more than something like a static or slighting dynamic maintenance page or serving a proxy pac file I'd recommend against it.
Maintenance Page.
Serving a Proxy Pac file
I need to clean up the formatting of the second link, but you'll get the idea.
Related
We currently run a SaaS application on apache which server ecommerce websites (its a store builder). We currently host over 1000 clients on that application and are now running into scalability issues (CPU going over 90% even on a fairly large 20 core 80GB ram + all SSD disk server).
We're looking for help from an nginx expert who can:
1. Explain the difference between running nginx as a web server vs. using it like a reverse proxy. What are the benefits?
2. We also want to use nginx as a load balancer (and have that already setup in testing), but we haven't enabled cacheing on the load balancer. So while its helping redirect requests, its not really serving any traffic directly and it simply passes through everything to one of the two apache servers.
The question is that we have a lot of user-generated content coming from the apache servers, how do we invalidate the cache for only certain pages that are being cached by nginx? If we setup a cron to clear this cache every 1 minute or so, it wouldn't be that useful... as cache would then be virtually non existent.
--
Also need an overall word on what is the best architecture to build for given the above scenarios.
Is it
NGINX Load Balancer + Cacheing ==> Nginx Web Server
NGINX Load Balancer ==> Nginx Web Server + Cacheing ?
NGINX Load Balancer + Cacheing ==> Apache Web Server
NGINX Load Balancer == > Apache Web Server (unlikely)
Please help!
Scaling horizontally to support more clients is a good option. Its recommended to first evaluate what is causing the bottleneck, memory within the application, long running requests etc.
Nginx Vs other web servers: Nginx is a HTTP server and not a servlet engine. Given that, you can check if it fits your needs.
It is a fast web server. You need to evaluate the benefits of using it as a single stand alone webserver against other web servers. Speed and memory could help.
Nginx as a load balancer:
You can have multiple web server instances behind nginx.
It supports load balancing algorithms like round robin, weighted etc so the load can be distributed based on the resource availability.
It helps in terminating ssl at Nginx, filter requests, modify headers,
compression, application upgrades wihtout downtime, serve cached content etc. This frees up resources on the server running the application. Also separation of concerns.
This setup is a reverse proxy and the benefits to it.
You can handle cache expiry with nginx. nginx documentaion has good details http://nginx.com/resources/admin-guide/caching/
I was wondering if it would be okay to run Tomcat as both the web server and container? On the other hand, it seems that the right way to go about scaling your webapp is to use Apache HTTP listening on port 80 and connecting that to Tomcat listening on another port?
Are both ways acceptable? What is being used nowdays? Whats the prime difference? How do most major websites go about this?
Thanks.
Placing an Apache (or any other webserver) in front of your application server(s) (Tomcat) is a good thing for a number of reasons.
First consideration is about static resources and caching.
Tomcat will probably serve also a lot of static content, or even on dynamic content it will send some caching directives to browsers. However, each browser that hits your tomcat for the first time will cause tomcat to send the static file. Since processing a request is a bit more expensive in Tomcat than it is in Apache (because of Apache being super-optimized and exploiting very low level stuff not always available in Tomcat, because Tomcat extracting much more informations from the request than Apache needs etc...), it may be better for the static files to be server by Apache.
Since however configuring Apache to serve part of the content and Tomcat for the rest or the URL space is a daunting task, it is usually easier to have Tomcat serve everything with the right cache headers, and Apache in front of it capturing the content, serving it to the requiring browser, and caching it so that other browser hitting the same file will get served directly from Apache without even disturbing Tomcat.
Other than static files, also many dynamic stuff may not need to be updated every millisecond. For example, a json loaded by the homepage that tells the user how much stuff is in your database, is an expensive query performed thousands of times that can safely be performed each hour or so without making your users angry. So, tomcat may serve the json with proper one hour caching directive, Apache will cache the json fragment and serve it to any browser requiring it for one hour. There are obviously a ton of other ways to implement it (a caching filter, a JPA cache that caches the query etc...), but sending proper cache headers and using Apache as a reverse proxy is quite easy, REST compliant and scales well.
Another consideration is load balancing. Apache comes with a nice load balancing module, that can help you scale your application on a number of Tomcat instances, supposed that your application can scale horizontally or run on a cluster.
A third consideration is about ulrs, headers etc.. From time to time you may need to change some urls, or remove or override some headers. For example, before a major update you may want to disable caching on browsers for some hours to avoid browsers keep using stale data (same as lowering the DNS TTL before switching servers), or move the old application on another url space, or rewrite old URLs to new ones when possible. While reconfiguring the servlets inside your web.xml files is possible, and filters can do wonders, if you are using a framework that interprets the URLs you may need to do a lot of work on your sitemap files or similar stuff.
Having Apache or another web server in front of Tomcat may help a lot changing only Apache configuration files with modules like mod_rewrite.
So, I always recommend having Apache httpd in front of Tomcat. The small overhead on connection handling is usually recovered thanks to caching of resources, and the additional configuration works is regained the first time you need to move URLs or handle some headers.
It depends on your network and how you wish to have security set up.
If you have a two-firewall DMZ, with applications deployed inside the second firewall, it makes sense to have an Apache or IIS instance in between the two firewalls to handle security and proxy calls into the app server. If it's acceptable to put the Tomcat instance in the DMZ you're free to do so. The only downside that I see is that you'll have to open a port in the second firewall to access a database inside. That might put the database at risk.
Another consideration is traffic. You don't say anything about traffic, sizing servers, and possible load balancing and clustering. A load balancer in front of a cluster of app servers is more likely to be kept inside the second firewall. The Tomcat instance is capable of handling traffic on its own, but there are always volume limitations depending on the hardware it's deployed on and what the application is doing with each request. It's almost impossible to give a yes or no answer without more detailed, application-specific information.
Search the site for "tomcat without apache" - it's been asked before. I voted to close before finding duplicates.
I'm trying to set up Apache in front of Tomcat. What do I have Apache serve? I know Apache works better for static pages and images. I currently deploy a war file in Tomcat that contains static pages, images, and Flash files. Should I put those all on the Apache server? How to I reference those pages/images from the Tomcat application?
I would like to use Apache to decrease the war file size and hopefully serve images faster. Is there a good guide for setting up Apache and Tomcat and what to place where?
Do you have a problem with performance/load on your Tomcat server? Do it if you need to(performance, security, etc), but don't make things more complicated if you don't need to.
It used to be the standard to front Tomcat with an Apache server, but recent versions of Tomcat can(and often times are) used as both the HTTP Server and the Servlet Container.
Take a look at the Tomcat Connector FAQ for information on the subject.
Why should I integrate Apache with
Tomcat? (or not)
There are many reasons to integrate
Tomcat with Apache. And there are
reasons why it should not be done too.
Needless to say, everyone will
disagree with the opinions here. With
the performance of Tomcat 5 and 6,
performance reasons become harder to
justify.
...
Speed. Apache is faster at serving
static content than Tomcat. But unless
you have a high traffic site, this
point is useless. But in some
scenarios, tomcat can be faster than
Apache httpd. So benchmark YOUR site.
Tomcat can perform at httpd speeds
when using the proper connector (APR
with sendFile enabled). Speed should
not be considered a factor when
choosing between Apache httpd and
Tomcat
I'm trying to set up Apache in front of Tomcat. What do I have Apache serve? I know Apache works better for static pages and images. I currently deploy a war file in Tomcat that contains static pages, images, and Flash files. Should I put those all on the Apache server? How to I reference those pages/images from the Tomcat application?
I would like to use Apache to decrease the war file size and hopefully serve images faster. Is there a good guide for setting up Apache and Tomcat and what to place where?
Do you have a problem with performance/load on your Tomcat server? Do it if you need to(performance, security, etc), but don't make things more complicated if you don't need to.
It used to be the standard to front Tomcat with an Apache server, but recent versions of Tomcat can(and often times are) used as both the HTTP Server and the Servlet Container.
Take a look at the Tomcat Connector FAQ for information on the subject.
Why should I integrate Apache with
Tomcat? (or not)
There are many reasons to integrate
Tomcat with Apache. And there are
reasons why it should not be done too.
Needless to say, everyone will
disagree with the opinions here. With
the performance of Tomcat 5 and 6,
performance reasons become harder to
justify.
...
Speed. Apache is faster at serving
static content than Tomcat. But unless
you have a high traffic site, this
point is useless. But in some
scenarios, tomcat can be faster than
Apache httpd. So benchmark YOUR site.
Tomcat can perform at httpd speeds
when using the proper connector (APR
with sendFile enabled). Speed should
not be considered a factor when
choosing between Apache httpd and
Tomcat
Recently our Software Analytic provider (NETTRACKER) sent us a plugin in order to be able to capture visitors in a better way. This plugin is for Apache 1.x and Apache 2.x. They said and I quote
that since Apache Tomcat is built on Apache HTTP server the configuration of the plugin should be the same.
I have looked for a httpd.conf in our tomcat deployment but we cannot find one, the only configuration that is similar to that one is the server.xml under the /conf directory.
If someone has better information regarding these two incredible products (Apache HTTP server and Apache Tomcat) I will greatly appreciate to draw the differences.
EDIT:
In case you are curious we know that Apache Web Server and Tomcat can work together using the mod_jk option and other proxys. But this will be too complex for our deployment.
Apache Tomcat and Apache HTTP are completely different server technologies. It is impossible to use a plugin for Apache HTTP server with Tomcat.
Apache HTTP server is developed in C and so are the plug-ins. On the contrary Tomcat is now completely developed in Java. Tomcat doesn't only serve static content, but it can also serve JSP pages and servlets.
Tomcat is used for hosting Java Web Applications. It can sure serve static content - you can host a web application using only Tomcat. Secure connections are supported and the performance is also very good (comparable with the performance of HTTP server).
A plain installation of Apache serves static content. Using the appropriate plug-ins, HTTP requests can be redirected to an application server (Tomcat, JBoss, Glassfish) or a script language interpreter (PHP). With this way dynamic content can be generated. The big advantages of Apache are the numerous plug-ins available, which allows administrators to configure and monitor web sites any way they want and that is the most widespread server available. This makes it the most secure solution, since it is thoroughly tested and any discovered flaw is corrected very quickly.
The best solution would be to use Tomcat proxied by an Apache server. It isn't so difficult to set up. If you can't do this, then you can't take advantage of Apache's plug-ins.
You see this confusion all the time. Many people think that Apache is a web server where in reality it is the name of an organization that has a web server project called "The Apache HTTP Server Project". In short the web server is called HTTPD (D as in daemon or Unix process).
Tomcat is another Apache project. This project implements a Java servlet engine to serve JSP pages and servlets. Tomcat and HTTPD have nothing to do with each other. However, you can set up HTTPD and Tomcat so that they work together. This way you can have HTTPD serve all static content, do URL rewriting and much more fancy stuff that the built in Tomcat web server can't do (or can't do very well). Whenever a JSP page is requested, HTTPD will pass the request on to Tomcat. Tomcat will process the request and will hand the output back to HTTPD which in turn will send it to the client.
Apache has many interesting projects. E.g. there is also a project called Geronimo which is a Java Enterprise server (J2EE). You can e.g. choose to embed Tomcat inside Geronimo to handle requests for JSP's and servlets where Geronimo does the more enterprisy stuff (LDAP, Messaging etc.). And you guessed it probably already, you can use HTTPD as a static content server for Geronimo as well.
totally bogus. Apache httpd plugins are written in C, Tomcat is pure Java.
Tomcat is a Java servlet engine. It can be hosted under Apache or IIS or quite a number of other external facing web servers. It sounds like you may be currently running your Tomcat instance standalone...
If you serve the JSP/servlets off of port 8080 and have it do things standalone, on the same host machine that Apache is running on, this can allow you to have them loosely coupled. Having multiple web servers fielding independent requests is not recommended, especially if you want to use server-based authentication along with Apache. Typically, you have one outside facing server that shepherds everything through it... Apache does this quite well, and the plugin you mention probably relies on this type of setup (everything gets wired through Apache) for its features/capabilities, based on your brief description of it.
If you would like to serve up your Tomcat servlets under Apache, you could configure apache to forward a class of URIs to your tomcat server instances. you could achieve this type of forwarding through mod_rewrite. this is a slower option performance-wise, as it adds slight overhead on everything you server up. You could also proxy incoming requests via a CGI mechanism similarly, from Apache to Tomcat.
mod_jk will simplify deployment and increase performance for placing Tomcat into an Apache server config. It is pretty painless to configure if you follow the docs, so I am not sure what you mean by "too complex" for your deployment -- if you want Apache and have Tomcat already, it would seem only a matter of slight config changes to get mod_jk downloaded and installed.