{"id":3270,"date":"2019-09-02T11:25:03","date_gmt":"2019-09-02T11:25:03","guid":{"rendered":"https:\/\/www.testpreptraining.com\/tutorial\/?page_id=3270"},"modified":"2020-05-02T05:31:51","modified_gmt":"2020-05-02T05:31:51","slug":"load-balancing","status":"publish","type":"page","link":"https:\/\/www.testpreptraining.ai\/tutorial\/aws-certified-solutions-architect-professional-sap-c01\/load-balancing\/","title":{"rendered":"Load Balancing"},"content":{"rendered":"\n<h3 class=\"wp-block-heading\"><strong>Elastic Load Balancers<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li>They allows us to balance load between different\nservers.<\/li><li>Types<ul><li>Application\nLoad Balancer : Layer 7. support advanced request routing based on HTTP request\ncharacteristics like path, headers, etc.<\/li><\/ul><ul><li>Network\nLoad Balancer : Very High Performance, Layer 4, Most expensive. Support\nmillions of request per second.<\/li><\/ul><ul><li>Classic\nLoad Balancer : Dumber Layer 7, Legacy. Also supports Layer 4. The only thing\nsupported at Layer 7 is X-Forwarded-For and sticky sessions.<\/li><\/ul><\/li><li>ELB responds with HTTP 504 Gateway Timeout when\nthe application does not respond.<\/li><li>The DNS names for the load balancers are\n{LB-name}.{region}-elb.amazonaws.com<\/li><li>The healthcheck statuses for instances behind LB\ncan be InService or OutOfService.<\/li><li>When a healtcheck for an instance fails, the\nload balancer stops sending traffic to that instance.<\/li><li>When configuring ELB health checks, bear in mind\nthat you may want to create a file like healthcheck.html or point the ping path\nof the health check to the main index file in application<\/li><li>Remember the health check interval is how often\na health check will occur<\/li><li>Healthy\/Unhealthy thresholds are how many times\neither will check before marking the origin either healthy or unhealthy<ul><li>Health\nCheck Interval: 10 seconds<\/li><\/ul><ul><li>Unhealthy\nThreshold: 2<\/li><\/ul><ul><li>Healthy\nThreshold: 3<\/li><\/ul><ul><li>This\nmeans that if the health check interval occurs twice without success, then the\nsource will be marked as unhealthy. This is 2 checks @ 10 seconds per check, so\nbasically after 20 seconds the origin will be marked unhealthy<\/li><\/ul><ul><li>Likewise,\nif the healthy threshold is marked at 3, then it would be 3 x health check\ninterval or 10 seconds being 30 seconds. After 30 seconds with 3 consecutive\nsuccess checks, the origin will be marked as healthy. <\/li><\/ul><\/li><li>Enable Cross-Zone Load Balancing will distribute\nload across all back-end instances, even if they exist in different AZ&#8217;s<\/li><li>ELBs are NEVER given public IP Addresses, only a\npublic DNS name<\/li><li>ELBs can be In Service or Out of Service\ndepending on health check results<\/li><li>Charged by the hour and on a per GB basis of\nusage<\/li><li>Must be configured with at least one listener<\/li><li>A listener must be configured with a protocol\nand a port for front end (client to ELB connection), as well as a protocol and\nport for backed end (ELB to instances connection)<\/li><li>ELBs support HTTP, HTTPS, TCP, and SSL (Secure\nTCP)<\/li><li>ELBs support all ports (1-65535)<\/li><li>ELBs do not support multiple SSL certificates<\/li><li>Classic ELBs support the following ports:<ul><li>25\n(SMTP)<\/li><\/ul><ul><li>80\n(HTTP)<\/li><\/ul><ul><li>443\n(HTTPS)<\/li><\/ul><ul><li>465\n(SMTPS)<\/li><\/ul><ul><li>587\n(SMTPS)<\/li><\/ul><ul><li>1024-65535<\/li><\/ul><\/li><\/ul>\n\n\n\n<p>ELB Error Messages<\/p>\n\n\n\n<p>HTTP Error Codes:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>200 &#8211; The request has succeeded<\/li><li>3xx &#8211; Redirection<\/li><li>4xx &#8211; Client Error (404 not found)<\/li><li>5xx &#8211; Server Error<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><td>\n   Application Load Balancer Limit\n   <\/td><td>\n   Default Limit\n   <\/td><\/tr><\/thead><tbody><tr><td>\n  Load balancers per region:\n  <\/td><td>\n  20\n  <\/td><\/tr><tr><td>\n  Target groups per region:\n  <\/td><td>\n  50\n  <\/td><\/tr><tr><td>\n  Listeners per load balancer:\n  <\/td><td>\n  10\n  <\/td><\/tr><tr><td>\n  Targets per load balancer:\n  <\/td><td>\n  1000\n  <\/td><\/tr><tr><td>\n  Subnets per Availability Zone per load balancer:\n  <\/td><td>\n  1\n  <\/td><\/tr><tr><td>\n  Security groups per load balancer:\n  <\/td><td>\n  5\n  <\/td><\/tr><tr><td>\n  Rules per load balancer (excluding defaults:\n  <\/td><td>\n  10\n  <\/td><\/tr><tr><td>\n  No. of times a target can be registered per LB:\n  <\/td><td>\n  100\n  <\/td><\/tr><tr><td>\n  Load balancers per target group:\n  <\/td><td>\n  1\n  <\/td><\/tr><tr><td>\n  Targets per target group :\n  <\/td><td>\n  1000\n  <\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><td>\n   Classic Load Balancer Limit\n   <\/td><td>\n   Default Limit\n   <\/td><\/tr><\/thead><tbody><tr><td>\n  Load balancers per region:\n  <\/td><td>\n  20\n  <\/td><\/tr><tr><td>\n  Listeners per load balancer:\n  <\/td><td>\n  100\n  <\/td><\/tr><tr><td>\n  Subnets per Availability Zone per load balancer:\n  <\/td><td>\n  1\n  <\/td><\/tr><tr><td>\n  Security groups per load balancer:\n  <\/td><td>\n  5\n  <\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Elastic Load Balancers They allows us to balance load between different servers. Types Application Load Balancer : Layer 7. support advanced request routing based on HTTP request characteristics like path, headers, etc. Network Load Balancer : Very High Performance, Layer 4, Most expensive. Support millions of request per second. Classic Load Balancer : Dumber Layer&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2471,"menu_order":53,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"categories":[2],"tags":[7,570],"class_list":["post-3270","page","type-page","status-publish","hentry","category-amazon-aws","tag-aws","tag-load-balancing"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.1 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Load Balancing - Testprep Training Tutorials<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.testpreptraining.ai\/tutorial\/aws-certified-solutions-architect-professional-sap-c01\/load-balancing\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Load Balancing - Testprep Training Tutorials\" \/>\n<meta property=\"og:description\" content=\"Elastic Load Balancers They allows us to balance load between different servers. 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