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76 lines
1.3 KiB
ReStructuredText
76 lines
1.3 KiB
ReStructuredText
Load Balancing
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**************
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Why do we use load balancers?
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=============================
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* A fast, HTTP/TCP based load balancer can distribute between slower application
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servers, and can keep each application server running optimally
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* They keep application servers busy by buffering responses and serving them to
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slow clients (or keepalives). We want app servers to do real work, not waste
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time waiting on the network.
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* Can be tuned by itself for max conns?
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* HTTP path based routing, 1 domain to multiple heterogeneous server pools.
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Software
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========
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Apache
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------
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Nginx
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-----
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HAProxy
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-------
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Hardware
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========
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BIG-IP
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------
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Netscaler
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---------
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Multi-dc
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========
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Anycast
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-------
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DNS GSLB
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--------
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CDN’s
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-----
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(cparedes: I’d argue that it’s valid in some contexts, depending on what
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you’re load balancing)
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Application implications
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========================
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Balancing algorithms
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--------------------
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Session Affinity, and why it is evil.
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-------------------------------------
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Local & ISP caching
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-------------------
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SSL Termination
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---------------
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Balancing vs. Failover (Active / Passive)
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-----------------------------------------
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Health Checks.
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---------------
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Non-HTTP use cases
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==================
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Native SMTP, or general TCP for things like RabbitMQ, MongoDB, etc
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