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10

There are couple of ways to achieve HA of a Load Balancer - or in that regards any service. Lets assume you have two machines, with IP addresses: 192.168.100.101 192.168.100.102 Users connect to an IP, so what you want to do is separate IP from specific box - eg create virtual IP. That IP will be 192.168.100.100. Now, you can choose HA service which ...


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In case you use nginx as a load-balancer, the stream will be : Redirect : Step 1 : Client => LB (HTTP request) Step 2 : LB => Client (HTTP reply) Step 3 : Client => Backend (HTTP request) Step 4 : Backend => Client (HTTP reply) Proxy : Step 1 : Client => LB (HTTP request) Step 2 : LB => Backend (HTTP request) ...


2

Hardware load balancers have supported "active/passive" or "active/active" setups for years, in both cases they are then set up in parallel from a layer 1/2 perspective... active/passive uses monitoring/keepalive mechanisms as described, active/active can be implemented in numerous ways. To appear as a single IP at the frontend, two or more balancers might, ...


2

The recommended way to do this is to have a custom health probe in your load balanced set. For example, you could have a simple healthcheck.html page on each of your VM's (in wwwroot for example) and direct the probe from your load balanced set to this page. As long as the probe can retrieve that page (HTTP 200), the Azure load balancer will keep sending ...


2

Using Nginx as your load balancer should allow you to follow the redirect detailed in this post by altering your config to detect a no response timeout: nginx automatic failover load balancing In theory if you have a HA environment, multiple load balancers clustered should allow service to be maintained if one was to fail. Hope this helps.


2

I doubt you'll get a positive answer. They may well use something like HAProxy, but the nature of the abstraction provided by ELB means they could probably swap that out for something else at any time. Also they probably have their own modifications to whatever they're using. However, if you're interested in the design of Load-Balancing-as-a-Service in ...


2

It depends what you tell nginx to do in your configuration and what proxying mode is set. If your use case is proxy_pass or fastcgi_pass this is controlled by proxy_http_version and fastcgi_keep_conn combined to the keepalive directive in the upstream server block.


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You have two possible approach : 1. A single VIP for both farms : In this case, your VIP will be your NGinx server single ip address. http { upstream web.example.com { least_conn; server mywebserver1.loc; server mywebserver2.loc; server mywebserver3.loc; } upstream api.example.com { least_conn; server myapiserver1.loc; ...


2

The question is: Each ISP has there own DNS, how to make the dns resolving based on the used ISP? Why do you care? The last time I used an ISP DNS was many many years ago. Run your own or go to the public Google DNS Servers. Finished. ISP's sometimes do crazy stuff with their DNS to "Improve service" - stuff that may break applications. If you avoid ...


1

I think the configuration options you require are: proxy_cache_use_stale updating; proxy_cache_lock on; This serves out of date elements from cache, and issuing updates from backend. So when your backend servers a page after 2 seconds, the client already got the old ressource from cache. The second locks one element from cache, while already a ...


1

I wrote up an extended blog post about how to do this with Apache 2.4 using OSSEC (a FOSS host-based intrusion detection system). Here's the TLDR: Use mod_remoteip to log client IPs in place of your load-balancer IPs. In your vhost config, use an IncludeOptional directive inside a RequireAll directive to source in a directory that will contain other ...


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In the following logs, sub.example.com represents a subdomain which is different from that actually being hosted by the servers in question. [Fri May 01 06:28:37.315175 2015] [ssl:debug] [pid 13873] ssl_engine_io.c(1201): (70014)End of file found: [client 10.0.0.123:37617] AH02007: SSL handshake interrupted by system [Hint: Stop button pressed in ...


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If the web application requires that a user stay connected to the same server, then the load balancer has to understand the session management method of the web application. For example, the load balancer can inject its own cookie in to the session that says which backend server to connect to. The load balancer can also read a cookie placed by the web app. ...



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