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Questions tagged [load-balancing]

Load balancing deal with the techniques involved on using multiple systems to deal with high demands, balancing the load between those multiple systems. Questions deal with networking and server load balancing, using dedicated hardware or not.

111
votes
5answers
57k views

What is the difference between Load Balancer and Reverse Proxy?

I'm not clear about the difference between Load Balancer and Reverse Proxy. They both seems having same behavior: distributing incoming requests to backend servers.
64
votes
18answers
61k views

Is Round-Robin DNS “good enough” for load balancing static content?

We have a set of shared, static content that we serve up between our websites at http://sstatic.net. Unfortunately, this content is not currently load balanced at all -- it's served from a single ...
63
votes
5answers
99k views

Does each server behind a load balancer need their own SSL certificate?

If you have 5 web servers behind a load balancer (such as haproxy) and they are serving up content for the same domain, do you need SSL certificates for all the servers, or can you use the same ...
45
votes
6answers
59k views

How can I remove balanced node from haproxy via command line?

I have haproxy running as my load-balancer and from the stats web interface that comes with haproxy, I can put a web server into maintenance mode (and bring it back out again) - which is great! ...
38
votes
4answers
95k views

How to set up stats for HAProxy?

I can't figure out how to set up stats for HAProxy. This is my configuration: global log 127.0.0.1 local0 log 127.0.0.1 local1 notice daemon #debug user haproxy group haproxy ...
30
votes
3answers
38k views

What kind of load balancing algorithms are there

I was researching different load balancing algorithms for HTTP and I just found 3. Random, Round Robin and Weighted Round Robin. Are there any other options? Thanks Paul
29
votes
2answers
24k views

Do HTTP reverse proxies typically enable HTTP Keep-Alive on the client side of the proxied connection and not on the server side?

HAProxy has the ability to enable HTTP keep-alive on the client side (client <-> HAProxy) but disable it on the server side (HAProxy <-> server). Some of our clients connect to our web service ...
28
votes
2answers
52k views

nginx automatic failover load balancing

I'm using nginx and NginxHttpUpstreamModule for loadbalancing. My config is very simple: upstream lb { server 127.0.0.1:8081; server 127.0.0.1:8082; } server { listen 89; ...
26
votes
5answers
35k views

Hardware vs Software load balancers: Just a cost issue?

If cost were not an issue, would there be any benefit in deploying a software load balancer for web traffic compared to a hardware one?
26
votes
2answers
35k views

HAProxy reqrep remove URI on backend request

real quick question regarding HAProxy reqrep. I am trying to rewrite/replace the request that gets sent to the backend. I have the following example domain and URIs, both sharing the same domain ...
25
votes
14answers
4k views

Load-balancer options [closed]

I am looking at a number of possible options for load-balancing. So far, I am constrained to the following options: DNS server load-balancer, balancing to a cluster of tomcat servers, with ...
25
votes
3answers
11k views

How can I deploy a scalable, reliable haproxy cluster on Amazon EC2?

We need some more advanced functionality than ELB provides (mostly L7 inspection), but it's not obvious how to handle things like heartbeat and high availability with something like haproxy using EC2. ...
24
votes
10answers
154k views

Point Multiple IP Addresses to a Single Host Name

In Windows System, there is this file at C:\WINDOWS\system32\drivers\etc\hosts. This file allows us to default a specific IP address to a host name. The issue now is whether I can set multiple IP ...
24
votes
3answers
12k views

How to make redundant load balancers?

I understand that the purpose of load balancers is to balance load between your servers and keep track of instance health, etc. But what if load balancer itself fails? How do you set up redundant load ...
22
votes
4answers
23k views

What are the Differences between HAProxy and Ngnix in reverse proxy mode?

What are the differences between HAProxy and Nginx when it comes to their abilities as a reverse proxy?
22
votes
6answers
8k views

What is a typical method to scale out a software load balancer?

I often see web app architectures with a SLB / reverse-proxy in front of a bunch of app servers. What happens when the number of connections to the SLB requires too many resources for a single SLB to ...
21
votes
5answers
39k views

How do I Install Intermediate Certificates (in AWS)?

I have installed private key (pem encoded) and public key certificate (pem encoded) on Amazon Load Balancer. However, when I check the SSL with site test tool, I get the following error: Error ...
21
votes
2answers
4k views

How is a single IP address load balanced?

I'm aware of "round robin DNS" load balancing, but how can a single IP address be load balanced? Google's DNS servers for example, 8.8.8.8 and 8.8.4.4. Wikipedia's load balancing article states: ...
20
votes
6answers
72k views

How can I use HAproxy with SSL and get X-Forwarded-For headers AND tell PHP that SSL is in use?

I have the following setup: (internet) ---> [ pfSense Box ] /-> [ Apache / PHP server ] [running HAproxy] --+--> [ Apache / PHP server ] ...
20
votes
2answers
22k views

LVS vs HAProxy, which should I choose?

I am looking for a solution to load balancing and failover strategy, mainly for big web applications. We have many services to be balanced, such as web, MySQL, and many other HTTP or TCP based ...
20
votes
3answers
21k views

Layer 4 vs Layer 7 Load Balancing

I am trying to decide between using a layer 4 load balancing solution for my datacenter or a layer 7 solution. Unfortunately (for my sanity, that is), my use case is simple enough that both solutions ...
19
votes
8answers
3k views

Software http load balancer?

Right now we only have one back-end server per site/web service. I'd be interested to hear people's experiences with various load balancer apps (something that runs on Linux). What would you ...
19
votes
3answers
24k views

Issues with EC2 Elastic Load Balancer DNS and routing

We're trying to run a fairly straightforward setup on Amazon EC2 - several HTTP servers sitting behind an Amazon Elastic Load Balancer (ELB). Our domain is managed in Route53, and we have a CNAME ...
19
votes
2answers
3k views

Outlook fails to connect to a load-balanced Exchange 2013 cluster through Direct Access 2012 R2

We have a load-balanced Exchange 2013 SP1 cluster, running MAPI over HTTP. Client connectivity inside our own network works just fine, while clients connected over Direct Access does not connect. The ...
18
votes
3answers
35k views

When using TCP load balancing with HAProxy, does all outbound traffic flow through the LB?

I am setting up an app to be hosted using VMs(probably amazon, but that is not set in stone) which will require both HTTP load balancing and load balancing a large number(50k or so if possible) of ...
18
votes
4answers
13k views

How to allow elastic load balancer through port 80 in security groups?

I want to temporarily block port 80 for the outside world, but want the load balancer to pass through the firewall (via security group) so it won't see the instance as unhealthy. How can I do that? ...
18
votes
3answers
21k views

EC2 Update my existing AMI

I'm using Elastic Load Balancing to load balance my Auto Scaling Group, for that I have a private AMI that hold my application server (Tomcat) and my web app deployed to it as war ... Now everything ...
17
votes
3answers
15k views

GlusterFS vs Ceph, which is better for production use for the moment? [closed]

I am evaluating GlusterFS and Ceph, seems Gluster is FUSE based which means it may be not as fast as Ceph. But looks like Gluster got a very friendly control panel and is ease to use. Ceph was ...
16
votes
1answer
30k views

How to divert traffic based on hostname using HAProxy?

I've had some initial success with HAProxy setting up a bunch of app servers listening on various other ports. I now have another webserver listening on one port, and i'd like to what changes to make ...
16
votes
3answers
7k views

Is there a way to add more backend server to haproxy without restarting haproxy?

We want to be able to add more backend servers on demand. Right now I don't see a way to add more backend servers to the config file without restarting haproxy.
16
votes
2answers
13k views

Redirect all HTTP traffic to HTTPS when using the HTTP(S) Load Balancer on Google Compute Engine

I have HTTP/HTTPS Load Balancing set up on Google Compute Engine with 2 Global Forwarding Rules (HTTP and HTTPS). Each rule points to a back-end service with a protocol of HTTP. I want all requests ...
15
votes
2answers
34k views

Load balancing & NAT-ing multiple ISP connections on Linux

I have two internet connections from two different ISPs and I need to balance the traffic originating to and from my network between the two ISPs. I am using Debian GNU/Linux. My set-up is like this -...
15
votes
2answers
2k views

Campus Network Design - Firewalls

I am designing a campus network, and the design looks like this: LINX is The London Internet Exchange and JANET is Joint Academic Network. My goal is an almost-fully redundant with high availability,...
15
votes
3answers
7k views

Multi-site high availability

We have a SaaS application that we need to be highly available. We already have an expensive, well-maintained Hyper-V failover cluster, but today the datacenter where we host that cluster had a five-...
15
votes
6answers
9k views

Solution to route/proxy SNMP Traps (or Netflow, generic UDP, etc) for network monitoring?

I'm implementing a network monitoring solution for a very large network (approximately 5000 network devices). We'd like to have all devices on our network send SNMP traps to a single box (technically ...
14
votes
3answers
25k views

How to setup HAProxy with failover?

I understand that, to get failover on an HAProxy load balancing setup, you need two machines running HAproxy (and route it to several webserver instances). But in this case, say abcd.com, how do we ...
14
votes
1answer
40k views

HAProxy - forward to a different web server based on URI

I have an HTTP farm with the following configuration: listen webfarm 10.254.23.225:80 mode http balance roundrobin cookie SERVERID insert option httpclose option ...
14
votes
3answers
17k views

How do you create a zone apex alias that points to a Elastic Load Balancer in the Route 53 GUI?

I created aliases for my domain name's zone apex using the ELB CLI as described in Elastic Load Balancing Developer Guide. I also added a AAAA record using the --rr-type AAAA flag, which is not ...
14
votes
1answer
4k views

Keepalive setting for Gunicorn behind ELB without Nginx

Our app's REST API is served by Gunicorn (not behind Nginx) running on AWS EC2 instances with a typical auto-scaling/load balancing setup. The load balancer's idle timeout is 60 seconds, and Gunicorn'...
14
votes
2answers
26k views

How does one point a domain to a load balancer that doesn't have a stable IP?

I'm trying to point mydomain.eu to an AWS load balancer, which, by its nature, does not have a stable IP, so I think I'm supposed to point the A record to a subdomain at Amazon, but as far as I can ...
14
votes
7answers
13k views

Wordpress Installation on Two Servers - Loadbalancing

I have to install wordpress (One Blog, one domain, for e.g. mycompany.com/blog) on two servers sharing one database on a different server, these two servers are behind a loadbalancer and the db would ...
13
votes
6answers
34k views

Windows replacement for HAProxy

It does not appear that there is a similar question to this already posted, so I will go ahead and ask. I am working on a project that could benefit from having two - four servers handling incoming ...
13
votes
4answers
19k views

RequestHeader with Apache environment variable

I have Apache set up as a load balancer. I wanted to make apache set the X-Forwarded-Proto header, but this doesn't work: RequestHeader set X-Forwarded-Proto "%{SERVER_PROTOCOL}e" The header gets ...
13
votes
3answers
45k views

What is the downside to sticky sessions with load balancers?

We have a web farm of IIS7 machines which work great. In front of them is an F5 Big-IP hardware load balancer, also working fine :) (source: www.f5.com) Currently we're using an ASP.NET State ...
13
votes
8answers
4k views

Load balancing Apache on a budget?

I am trying to get my head around the concept of load balancing to ensure availability and redundancy to keep users happy when things go wrong, rather than load balancing for the sake of offering ...
13
votes
2answers
21k views

What algorithm does Amazon ELB use to balance load?

I found this in the official ELB documentation By default, a load balancer routes each request independently to the application instance with the smallest load. but an article on Newvem says ...
13
votes
2answers
8k views

nginx failover without load balancing

I'm having trouble configuring nginx. I'm using nignx as a reverse proxy. I want to send my all requests to my first server. If the first server is down, I want to send requests to second server. In ...
12
votes
6answers
10k views

Best way to load balance across multiple static file servers for even an bandwidth distribution?

First off, I'll explain my situation to you. I'm running a fairly popular website as a side project, so I can't really invest a ton of money into it. I currently have just one server with HAProxy in ...
12
votes
7answers
4k views

How can I balance incoming web traffic amongst N apache servers?

I am looking to use something like Heartbeat/Squid/Varnish/etc to balance the amount of incoming traffic amongst the internal apache instances. This would have to be software and not hardware as all ...
12
votes
5answers
17k views

How to load-balance SQL Server 2008 for high-usage ASP.NET applications?

Imagine that you have a successful web application that uses ASP.NET and IIS 7. It generates many calls to a SQL Server 2008 database, and is expected to be available to the public with 99.9% uptime (...